mybatis

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我是靠谱客的博主专注大象，最近开发中收集的这篇文章主要介绍mybatis，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

- 第一章 MyBatis-Plus3概述
- - 1.1、简介
  - 1.2、特性
  - 1.3、框架结构
  - 1.4、项目地址
  - 1.5、版本介绍
  - 1.6、快速安装
  - 1.7、开发环境
- 第二章 MyBatis-Plus3增删改查
- - 2.1、项目搭建
  - 2.2、项目配置（1）
  - 2.3、项目配置（2）
  - 2.4、数据导入
  - 2.5、创建实体
  - 2.6、创建接口
  - 2.7、测试准备
  - 2.8、增删改查
  - - 2.8.1、insert
    - 2.8.2、updateById
    - 2.8.3、selectById
    - 2.8.4、selectByMap
    - 2.8.5、selectBatchIds
    - 2.8.6、deleteById
    - 2.8.7、deleteByMap
    - 2.8.8、deleteBatchIds
- 第三章 MyBatis-Plus3注解介绍
- - 3.1、@TableName
  - 3.2、@TableId
  - 3.3、@TableField
  - 3.4、@Version
  - 3.5、@EnumValue
  - 3.6、@TableLogic
  - 3.7、@SqlParser
  - 3.8、@KeySequence
- 第四章 MyBatis-Plus3条件构造器
- - 4.1、数据导入
  - 4.2、构造器简介
  - 4.3、构造器使用（1）
  - - 4.3.1、带条件的查询
    - 4.3.2、带条件的修改
    - 4.3.3、带条件的删除
  - 4.4、构造器使用（2）
  - - 4.4.1、allEq
    - 4.4.2、eq
    - 4.4.3、ne
    - 4.4.4、gt
    - 4.4.5、ge
    - 4.4.6、lt
    - 4.4.7、le
    - 4.4.8、between
    - 4.4.9、notBetween
    - 4.4.10、like
    - 4.4.11、notLike
    - 4.4.12、likeLeft
    - 4.4.13、likeRight
    - 4.4.14、isNull
    - 4.4.15、isNotNull
    - 4.4.16、in
    - 4.4.17、notIn
    - 4.4.18、inSql
    - 4.4.19、notInSql
    - 4.4.20、groupBy
    - 4.4.21、orderByAsc
    - 4.4.22、orderByDesc
    - 4.4.23、orderBy
    - 4.4.24、having
    - 4.4.25、func
    - 4.4.26、or
    - 4.4.27、and
    - 4.4.28、nested
    - 4.4.29、apply
    - 4.4.30、last
    - 4.4.31、exists
    - 4.4.32、notExists
- 第五章 MyBatis-Plus3代码生成器
- - 5.1、数据导入
  - 5.2、代码生成器简介
  - 5.3、代码生成器使用
  - - 5.3.1、添加依赖
    - 5.3.2、添加配置
    - 5.3.3、启动配置
    - 5.3.4、代码生成
    - 5.3.5、工程结构
    - 5.3.6、添加代码
    - 5.3.7、启动运行
    - 5.3.8、测试方法
    - 5.3.9、温馨提示
  - 5.4、代码生成器方法
  - - 5.4.1、save
    - 5.4.2、saveOrUpdate
    - 5.4.3、remove
    - 5.4.4、update
    - 5.4.5、get
    - 5.4.6、list
    - 5.4.7、page
    - 5.4.8、count
    - 5.4.9、chain
- 第六章 MyBatis-Plus3配置详解
- - 6.1、配置概述
  - 6.2、配置方式
  - 6.3、配置选项
  - - 6.3.1、mapperLocations
    - 6.3.2、typeAliasesPackage
    - 6.3.3、typeHandlersPackage
    - 6.3.4、typeEnumsPackage
    - 6.3.5、checkConfigLocation
    - 6.3.6、executorType
    - 6.3.7、configurationProperties
    - 6.3.8、configuration
    - - 6.3.8.1、mapUnderscoreToCamelCase
      - 6.3.8.2、defaultEnumTypeHandler
      - 6.3.8.3、aggressiveLazyLoading
      - 6.3.8.4、autoMappingBehavior
      - 6.3.8.5、autoMappingUnknownColumnBehavior
      - 6.3.8.6、localCacheScope
      - 6.3.8.7、cacheEnabled
      - 6.3.8.8、callSettersOnNulls
      - 6.3.8.9、configurationFactory
      - 6.3.8.10、MyBatis3的配置属性
    - 6.3.9、globalConfig
    - - 6.3.9.1、banner
      - 6.3.9.2、enableSqlRunner
      - 6.3.9.3、superMapperClass
      - 6.3.9.4、dbConfig
      - 6.3.9.4.1、idType
        6.3.9.4.2、tablePrefix
        6.3.9.4.3、schema
        6.3.9.4.4、columnFormat
        6.3.9.4.5、propertyFormat
        6.3.9.4.6、tableUnderline
        6.3.9.4.7、capitalMode
        6.3.9.4.8、logicDeleteField
        6.3.9.4.9、logicDeleteValue
        6.3.9.4.10、logicNotDeleteValue
        6.3.9.4.11、insertStrategy
        6.3.9.4.12、updateStrategy
        6.3.9.4.13、selectStrategy
  - 6.4、配置小结
- 第七章 MyBatis-Plus3插件扩展
- - 7.1、分页插件
  - 7.2、执行分析插件
  - 7.3、性能分析插件
  - 7.4、乐观锁插件
  - 7.5、快速开发插件
- 第八章 MyBatis-Plus3其它功能
- - 8.1、Sql 注入器
  - 8.2、逻辑删除
  - 8.3、通用枚举
  - - 8.3.1、保存枚举值
    - 8.3.2、保存枚举名称
  - 8.4、自动填充功能
  - 8.5、字段类型处理器
  - 8.6、自定义ID生成器
  - 8.7、Sequence主键

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第一章 MyBatis-Plus3概述

1.1、简介

MyBatis-Plus（简称 MP）是一个 MyBatis 的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。

我们的愿景是成为 MyBatis 最好的搭档，就像魂斗罗中的1P、2P，基友搭配，效率翻倍。

1.2、特性

无侵入：只做增强不做改变，引入它不会对现有工程产生影响，如丝般顺滑
损耗小：启动即会自动注入基本 CURD，性能基本无损耗，直接面向对象操作
强大的 CRUD 操作：内置通用 Mapper、通用 Service，仅仅通过少量配置即可实现单表大部分 CRUD 操作，更有强大的条件构造器，满足各类使用需求
支持 Lambda 形式调用：通过 Lambda 表达式，方便的编写各类查询条件，无需再担心字段写错
支持主键自动生成：支持多达 4 种主键策略（内含分布式唯一 ID 生成器 - Sequence），可自由配置，完美解决主键问题
支持 ActiveRecord 模式：支持 ActiveRecord 形式调用，实体类只需继承 Model 类即可进行强大的 CRUD 操作
支持自定义全局通用操作：支持全局通用方法注入（ Write once, use anywhere ）
内置代码生成器：采用代码或者 Maven 插件可快速生成 Mapper 、 Model 、 Service 、 Controller 层代码，支持模板引擎，更有超多自定义配置等您来使用
内置分页插件：基于 MyBatis 物理分页，开发者无需关心具体操作，配置好插件之后，写分页等同于普通 List 查询
分页插件支持多种数据库：支持 MySQL、MariaDB、Oracle、DB2、H2、HSQL、SQLite、Postgre、SQLServer 等多种数据库
内置性能分析插件：可输出 Sql 语句以及其执行时间，建议开发测试时启用该功能，能快速揪出慢查询
内置全局拦截插件：提供全表 delete 、 update 操作智能分析阻断，也可自定义拦截规则，预防误操作

1.3、框架结构

framework

1.4、项目地址

官网地址：点击打开

源码地址：点击打开

文档地址：点击打开

配置地址：点击打开

1.5、版本介绍

全新的 MyBatis-Plus 3.0 版本基于 JDK8，提供了 lambda 形式的调用，所以安装集成 MP3.0 要求如下：

JDK 8+
Maven or Gradle

1.6、快速安装

Spring Boot

Maven：

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.4.0</version>
</dependency>

       
       
       
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Gradle：

compile group: 'com.baomidou', name: 'mybatis-plus-boot-starter', version: '3.4.0'

       
       
       
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Spring MVC

Maven：

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus</artifactId>
    <version>3.4.0</version>
</dependency>

       
       
       
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Gradle：

compile group: 'com.baomidou', name: 'mybatis-plus', version: '3.4.0'

       
       
       
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警告：引入 MyBatis-Plus 之后请不要再次引入 MyBatis 以及 MyBatis-Spring，以避免因版本差异导致的问题。

1.7、开发环境

Jdk：jdk1.8.0_261
Idea：IntelliJ IDEA 2020.1.2 x64
Maven：apache-maven-3.3.9
MySQL：mysql-5.5.61-win64

第二章 MyBatis-Plus3增删改查

2.1、项目搭建

新建完成以后，打开pom.xml后添加以下依赖：

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.4.0</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.49</version>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.12</version>
    <scope>provided</scope>
</dependency>

   
   
   
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在src/mian/java目录中，创建以下包文件

com.caochenlei.mpdemo.pojo
com.caochenlei.mpdemo.mapper

2.2、项目配置（1）

MyBatis-Plus 的配置异常的简单，我们仅需要一些简单的配置即可使用 MyBatis-Plus 的强大功能！

Spring Boot 工程：

配置 MapperScan 注解

@SpringBootApplication
@MapperScan("com.caochenlei.mpdemo.mapper")
public class MpDemoApplication {
<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    SpringApplication<span class="token punctuation">.</span><span class="token function">run</span><span class="token punctuation">(</span>MpDemoApplication<span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">,</span> args<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}

Spring MVC 工程：

配置 MapperScan 对象

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.caochenlei.mpdemo.mapper"/>
</bean>

    
    
    
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调整 SqlSessionFactory 为 MyBatis-Plus 的 SqlSessionFactory

<bean id="sqlSessionFactory" class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
</bean>

    
    
    
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2.3、项目配置（2）

application.properties

#mysql
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/mp?useUnicode=true&characterEncoding=utf8
spring.datasource.username=root
spring.datasource.password=123456

#mybatis-plus
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

2.4、数据导入

## 创建库
CREATE DATABASE mp;
## 使用库
USE mp;
## 创建表
CREATE TABLE tbl_employee(
   id INT(11) PRIMARY KEY AUTO_INCREMENT,
   last_name VARCHAR(50),
   email VARCHAR(50),
   gender CHAR(1),
   age INT
);
## 导入数据
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom','tom@qq.com',1,22);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Jerry','jerry@qq.com',0,25);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Black','black@qq.com',1,30);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('White','white@qq.com',0,35);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tiger','tiger@qq.com',1,28);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Bobby','bobby@qq.com',0,16);
## 查询数据
SELECT * FROM tbl_employee;

 
 
 
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2.5、创建实体

com.caochenlei.mpdemo.pojo.Employee

@TableName("tbl_employee")
public class Employee {
    @TableId(value = "id", type = IdType.AUTO)
    private Integer id;
    @TableField(value = "last_name")
    private String lastName;
    @TableField(value = "email")
    private String email;
    @TableField(value = "gender")
    private Integer gender;
    @TableField(value = "age")
    private Integer age;
<span class="token keyword">public</span> <span class="token function">Employee</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span><span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token function">Employee</span><span class="token punctuation">(</span>Integer id<span class="token punctuation">,</span> String lastName<span class="token punctuation">,</span> String email<span class="token punctuation">,</span> Integer gender<span class="token punctuation">,</span> Integer age<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>id <span class="token operator">=</span> id<span class="token punctuation">;</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>lastName <span class="token operator">=</span> lastName<span class="token punctuation">;</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>email <span class="token operator">=</span> email<span class="token punctuation">;</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>gender <span class="token operator">=</span> gender<span class="token punctuation">;</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>age <span class="token operator">=</span> age<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> Integer <span class="token function">getId</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">return</span> id<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setId</span><span class="token punctuation">(</span>Integer id<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>id <span class="token operator">=</span> id<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> String <span class="token function">getLastName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">return</span> lastName<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setLastName</span><span class="token punctuation">(</span>String lastName<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>lastName <span class="token operator">=</span> lastName<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> String <span class="token function">getEmail</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">return</span> email<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setEmail</span><span class="token punctuation">(</span>String email<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>email <span class="token operator">=</span> email<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> Integer <span class="token function">getGender</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">return</span> gender<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setGender</span><span class="token punctuation">(</span>Integer gender<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>gender <span class="token operator">=</span> gender<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> Integer <span class="token function">getAge</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">return</span> age<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setAge</span><span class="token punctuation">(</span>Integer age<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>age <span class="token operator">=</span> age<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">return</span> <span class="token string">"Employee{"</span> <span class="token operator">+</span>
            <span class="token string">"id="</span> <span class="token operator">+</span> id <span class="token operator">+</span>
            <span class="token string">", lastName='"</span> <span class="token operator">+</span> lastName <span class="token operator">+</span> <span class="token string">'''</span> <span class="token operator">+</span>
            <span class="token string">", email='"</span> <span class="token operator">+</span> email <span class="token operator">+</span> <span class="token string">'''</span> <span class="token operator">+</span>
            <span class="token string">", gender="</span> <span class="token operator">+</span> gender <span class="token operator">+</span>
            <span class="token string">", age="</span> <span class="token operator">+</span> age <span class="token operator">+</span>
            <span class="token string">'}'</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}

2.6、创建接口

com.caochenlei.mpdemo.mapper.EmployeeMapper

@Repository
public interface EmployeeMapper extends BaseMapper<Employee> {

}

2.7、测试准备

com.caochenlei.mpdemo.MpDemoApplicationTests

@SpringBootTest
class MpDemoApplicationTests {
    @Autowired
    private EmployeeMapper employeeMapper;
<span class="token annotation punctuation">@Test</span>
<span class="token keyword">void</span> <span class="token function">contextLoads</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    List<span class="token generics function"><span class="token punctuation">&lt;</span>Employee<span class="token punctuation">&gt;</span></span> employees <span class="token operator">=</span> employeeMapper<span class="token punctuation">.</span><span class="token function">selectList</span><span class="token punctuation">(</span>null<span class="token punctuation">)</span><span class="token punctuation">;</span>
    employees<span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span>System<span class="token punctuation">.</span>out<span class="token operator">:</span><span class="token operator">:</span>println<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}

2.8、增删改查

2.8.1、insert

需求描述：插入一个员工，员工姓名为“张三”、邮箱为"zhangsan@qq.com"、男性、25岁

@Test
void testInsert() {
    int result = employeeMapper.insert(new Employee(null, "zhangsan", "zhangsan@qq.com", 0, 25));
    System.out.println("result:" + result);
}

 
 
 
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2.8.2、updateById

需求信息：将id为1的员工的姓名更改为"Jennie"

@Test
void testUpdateById() {
    // 先查询
    Employee employee = employeeMapper.selectById(1);
    employee.setLastName("Jennie");
    // 再修改
    int result = employeeMapper.updateById(employee);
    System.out.println(result);
}

 
 
 
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2.8.3、selectById

需求描述：查询id为1的员工信息

@Test
void testSelectById() {
    Employee employee = employeeMapper.selectById(1);
    System.out.println(employee);
}

 
 
 
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2.8.4、selectByMap

需求描述：查询性别为男性（0）且年龄在25岁的员工信息

@Test
void testSelectByMap() {
    Map<String, Object> map = new HashMap<>();
    map.put("gender",0);
    map.put("age",25);
    List<Employee> employees = employeeMapper.selectByMap(map);
    employees.forEach(System.out::println);
}

 
 
 
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2.8.5、selectBatchIds

需求描述：查询id分别为1、2、3的员工的信息

@Test
void testSelectBatchIds() {
    List<Employee> employees = employeeMapper.selectBatchIds(Arrays.asList(1, 2, 3));
    employees.forEach(System.out::println);
}

 
 
 
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2.8.6、deleteById

需求信息：删除id为1的员工信息

@Test
void testDeleteById() {
    int result = employeeMapper.deleteById(1);
    System.out.println(result);
}

 
 
 
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2.8.7、deleteByMap

需求描述：删除性别为男性（0）且年龄在25岁的员工信息

@Test
void testDeleteByMap() {
    Map<String, Object> map = new HashMap<>();
    map.put("gender", 0);
    map.put("age", 25);
    int result = employeeMapper.deleteByMap(map);
    System.out.println(result);
}

 
 
 
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2.8.8、deleteBatchIds

需求描述：删除id分别为4、5、6的员工的信息

@Test
void testDeleteBatchIds() {
    int result = employeeMapper.deleteBatchIds(Arrays.asList(4, 5, 6));
    System.out.println(result);
}

 
 
 
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第三章 MyBatis-Plus3注解介绍

3.1、@TableName

描述：表名注解

属性	类型	必须指定	默认值	描述
value	String	否	“”	表名
schema	String	否	“”	schema
keepGlobalPrefix	boolean	否	false	是否保持使用全局的 tablePrefix 的值(如果设置了全局 tablePrefix 且自行设置了 value 的值)
resultMap	String	否	“”	xml 中 resultMap 的 id
autoResultMap	boolean	否	false	是否自动构建 resultMap 并使用(如果设置 resultMap 则不会进行 resultMap 的自动构建并注入)

3.2、@TableId

描述：主键注解

属性	类型	必须指定	默认值	描述
value	String	否	“”	主键字段名
type	Enum	否	IdType.NONE	主键类型

IdType

值	描述
AUTO	数据库ID自增
NONE	无状态,该类型为未设置主键类型(注解里等于跟随全局,全局里约等于 INPUT)
INPUT	insert前自行set主键值
ASSIGN_ID	分配ID(主键类型为Number(Long和Integer)或String)(since 3.3.0),使用接口`IdentifierGenerator`的方法`nextId`(默认实现类为`DefaultIdentifierGenerator`雪花算法)
ASSIGN_UUID	分配UUID,主键类型为String(since 3.3.0),使用接口`IdentifierGenerator`的方法`nextUUID`(默认default方法)

3.3、@TableField

描述：字段注解(非主键)

属性	类型	必须指定	默认值	描述
value	String	否	“”	数据库字段名
el	String	否	“”	映射为原生 `#{ ... }` 逻辑,相当于写在 xml 里的 `#{ ... }` 部分
exist	boolean	否	true	是否为数据库表字段
condition	String	否	“”	字段 `where` 实体查询比较条件,有值设置则按设置的值为准,没有则为默认全局的 `%s=#{%s}`
update	String	否	“”	字段 `update set` 部分注入, 例如：update="%s+1"：表示更新时会set version=version+1(该属性优先级高于 `el` 属性)
insertStrategy	Enum	N	DEFAULT	举例：NOT_NULL: `insert into table_a(<if test="columnProperty != null">column</if>) values (<if test="columnProperty != null">#{columnProperty}</if>)`
updateStrategy	Enum	N	DEFAULT	举例：IGNORED: `update table_a set column=#{columnProperty}`
whereStrategy	Enum	N	DEFAULT	举例：NOT_EMPTY: `where <if test="columnProperty != null and columnProperty!=''">column=#{columnProperty}</if>`
fill	Enum	否	FieldFill.DEFAULT	字段自动填充策略
select	boolean	否	true	是否进行 select 查询
keepGlobalFormat	boolean	否	false	是否保持使用全局的 format 进行处理
jdbcType	JdbcType	否	JdbcType.UNDEFINED	JDBC类型 (该默认值不代表会按照该值生效)
typeHandler	Class<? extends TypeHandler>	否	UnknownTypeHandler.class	类型处理器 (该默认值不代表会按照该值生效)
numericScale	String	否	“”	指定小数点后保留的

FieldStrategy

值	描述
IGNORED	忽略判断
NOT_NULL	非NULL判断
NOT_EMPTY	非空判断(只对字符串类型字段,其他类型字段依然为非NULL判断)
DEFAULT	追随全局配置

FieldFill

值	描述
DEFAULT	默认不处理
INSERT	插入时填充字段
UPDATE	更新时填充字段
INSERT_UPDATE	插入和更新时填充字段

3.4、@Version

描述：乐观锁注解、标记 @Verison 在字段上

3.5、@EnumValue

描述：通枚举类注解（注解在枚举字段上）

3.6、@TableLogic

描述：表字段逻辑处理注解（逻辑删除）

属性	类型	必须指定	默认值	描述
value	String	否	“”	逻辑未删除值
delval	String	否	“”	逻辑删除值

3.7、@SqlParser

描述：租户注解，支持method上以及mapper接口上

属性	类型	必须指定	默认值	描述
filter	boolean	否	false	true: 表示过滤SQL解析，即不会进入ISqlParser解析链，否则会进解析链并追加例如tenant_id等条件

3.8、@KeySequence

描述：序列主键策略 oracle

属性：value、resultMap

属性	类型	必须指定	默认值	描述
value	String	否	“”	序列名
clazz	Class	否	Long.class	id的类型, 可以指定String.class，这样返回的Sequence值是字符串"1"

第四章 MyBatis-Plus3条件构造器

4.1、数据导入

## 使用库
USE mp;
## 清空表
TRUNCATE TABLE tbl_employee;	
## 导入数据
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan0','123@qq.com',0,21);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan1','123@qq.com',0,22);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan2','123@qq.com',0,23);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan3','123@qq.com',0,24);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan4','123@qq.com',0,25);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan5','123@qq.com',0,26);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan6','123@qq.com',0,27);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan7','123@qq.com',0,28);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan8','123@qq.com',0,29);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Allan9','123@qq.com',0,30);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby0','123@qq.com',1,21);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby1','123@qq.com',0,22);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby2','123@qq.com',1,23);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby3','123@qq.com',0,24);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby4','123@qq.com',1,25);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby5','123@qq.com',0,26);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby6','123@qq.com',1,27);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby7','123@qq.com',0,28);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby8','123@qq.com',1,29);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Baby9','123@qq.com',0,30);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom0','123@qq.com',1,21);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom1','123@qq.com',0,22);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom2','123@qq.com',1,23);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom3','123@qq.com',0,24);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom4','123@qq.com',1,25);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom5','123@qq.com',0,26);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom6','123@qq.com',1,27);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom7','123@qq.com',0,28);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom8','123@qq.com',1,29);
INSERT INTO tbl_employee(last_name,email,gender,age) VALUES('Tom9','123@qq.com',0,30);
## 查询数据
SELECT * FROM tbl_employee;

 
 
 
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4.2、构造器简介

MyBatis-Plus 通过 EntityWrapper（简称 EW，MP 封装的一个查询条件构造器）或者 Condition（与 EW 类似）来让用户自由的构建查询条件，简单便捷，没有额外的负担，能够有效提高开发效率，它主要用于处理 sql 拼接，排序，实体参数查询等。

注意：使用的是数据库字段，不是 Java 属性！

警告：MyBatis-Plus不支持以及不赞成在 RPC 调用中把 Wrapper 进行传输，Wrapper 很重，传输 Wrapper 可以类比为你的 controller 用 map 接收值(开发一时爽，维护火葬场)，正确的 RPC 调用姿势是写一个 DTO 进行传输，被调用方再根据 DTO 执行相应的操作。

4.3、构造器使用（1）

4.3.1、带条件的查询

需求描述：查询所有姓名的包含B、且姓名为女（1）、且年龄大于24岁的员工信息

@Test
void testSelectList1() {
    QueryWrapper<Employee> queryWrapper = new QueryWrapper<>();
    queryWrapper
            .like("last_name","B")
            .eq("gender",1)
            .gt("age",24);
    List<Employee> employees = employeeMapper.selectList(queryWrapper);
    employees.forEach(System.out::println);
}

 
 
 
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需求描述：查询所有员工信息

@Test
void testSelectList2() {
    List<Employee> employees = employeeMapper.selectList(null);
    employees.forEach(System.out::println);
}

 
 
 
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需求描述：查询所有女生的数量（1）

@Test
void testSelectList3() {
    QueryWrapper<Employee> queryWrapper = new QueryWrapper<>();
    queryWrapper.eq("gender", 1);
    Integer count = employeeMapper.selectCount(queryWrapper);
    System.out.println(count);
}

 
 
 
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4.3.2、带条件的修改

需求信息：将年龄大于25岁的女生（1）的性别修改为男生（0）

@Test
void testUpdate() {
    UpdateWrapper<Employee> updateWrapper = new UpdateWrapper<>();
    updateWrapper
        .eq("gender", 1)
        .gt("age", 25)
        ;
    Employee employee = new Employee();
    employee.setGender(0);
    employeeMapper.update(employee, updateWrapper);
}

 
 
 
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4.3.3、带条件的删除

需求信息：将姓名带有“Tom”的员工信息删除

@Test
void testDelete() {
    QueryWrapper<Employee> queryWrapper = new QueryWrapper<>();
    queryWrapper.like("last_name", "Tom");
    int result = employeeMapper.delete(queryWrapper);
    System.out.println(result);
}

 
 
 
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4.4、构造器使用（2）

参数说明：

以下出现的第一个入参boolean condition表示该条件是否加入最后生成的sql中
以下代码块内的多个方法均为从上往下补全个别boolean类型的入参，默认为true
以下出现的泛型Param均为Wrapper的子类实例(均具有AbstractWrapper的所有方法)
以下方法在入参中出现的R为泛型，在普通wrapper中是String，在LambdaWrapper中是函数(例：Entity::getId,Entity为实体类，getId为字段id的getMethod)
以下方法入参中的R column均表示数据库字段，当R具体类型为String时则为数据库字段名(字段名是数据库关键字的自己用转义符包裹)！而不是实体类数据字段名，另当R具体类型为SFunction时项目runtime不支持eclipse自家的编译器
以下举例均为使用普通wrapper，入参为Map和List的均以json形式表现
使用中如果入参的Map或者List为空，则不会加入最后生成的sql中

AbstractWrapper：

说明：AbstractWrapper 是 QueryWrapper(LambdaQueryWrapper) 和 UpdateWrapper(LambdaUpdateWrapper) 的父类用于生成 sql 的 where 条件，entity 属性也用于生成 sql 的 where 条件，注意 entity 生成的 where 条件与使用各个 api 生成的 where 条件没有任何关联行为

4.4.1、allEq

allEq(Map<R, V> params)
allEq(Map<R, V> params, boolean null2IsNull)
allEq(boolean condition, Map<R, V> params, boolean null2IsNull)

 
 
 
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全部 eq (或个别 isNull）

个别参数说明：

params：key为数据库字段名，value为字段值
null2IsNull：为true则在map的value为null时调用 isNull方法，为false时则忽略value为null的

例1: allEq({id:1,name:"老王",age:null})—>id = 1 and name = '老王' and age is null
例2: allEq({id:1,name:"老王",age:null}, false)—>id = 1 and name = '老王'

allEq(BiPredicate<R, V> filter, Map<R, V> params)
allEq(BiPredicate<R, V> filter, Map<R, V> params, boolean null2IsNull)
allEq(boolean condition, BiPredicate<R, V> filter, Map<R, V> params, boolean null2IsNull) 

 
 
 
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个别参数说明：

filter : 过滤函数，是否允许字段传入比对条件中
params 与 null2IsNull : 同上

例1: allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null})—>name = '老王' and age is null
例2: allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null}, false)—>name = '老王'

4.4.2、eq

eq(R column, Object val)
eq(boolean condition, R column, Object val)

 
 
 
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等于 =
例: eq("name", "老王")—>name = '老王'

4.4.3、ne

ne(R column, Object val)
ne(boolean condition, R column, Object val)

 
 
 
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不等于 <>
例: ne("name", "老王")—>name <> '老王'

4.4.4、gt

gt(R column, Object val)
gt(boolean condition, R column, Object val)

 
 
 
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大于 >
例: gt("age", 18)—>age > 18

4.4.5、ge

ge(R column, Object val)
ge(boolean condition, R column, Object val)

 
 
 
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大于等于 >=
例: ge("age", 18)—>age >= 18

4.4.6、lt

lt(R column, Object val)
lt(boolean condition, R column, Object val)

 
 
 
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小于 <
例: lt("age", 18)—>age < 18

4.4.7、le

le(R column, Object val)
le(boolean condition, R column, Object val)

 
 
 
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小于等于 <=
例: le("age", 18)—>age <= 18

4.4.8、between

between(R column, Object val1, Object val2)
between(boolean condition, R column, Object val1, Object val2)

 
 
 
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BETWEEN 值1 AND 值2
例: between("age", 18, 30)—>age between 18 and 30

4.4.9、notBetween

notBetween(R column, Object val1, Object val2)
notBetween(boolean condition, R column, Object val1, Object val2)

 
 
 
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NOT BETWEEN 值1 AND 值2
例: notBetween("age", 18, 30)—>age not between 18 and 30

4.4.10、like

like(R column, Object val)
like(boolean condition, R column, Object val)

 
 
 
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LIKE ‘%值%’
例: like("name", "王")—>name like '%王%'

4.4.11、notLike

notLike(R column, Object val)
notLike(boolean condition, R column, Object val)

 
 
 
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NOT LIKE ‘%值%’
例: notLike("name", "王")—>name not like '%王%'

4.4.12、likeLeft

likeLeft(R column, Object val)
likeLeft(boolean condition, R column, Object val)

 
 
 
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LIKE ‘%值’
例: likeLeft("name", "王")—>name like '%王'

4.4.13、likeRight

likeRight(R column, Object val)
likeRight(boolean condition, R column, Object val)

 
 
 
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LIKE ‘值%’
例: likeRight("name", "王")—>name like '王%'

4.4.14、isNull

isNull(R column)
isNull(boolean condition, R column)

 
 
 
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字段 IS NULL
例: isNull("name")—>name is null

4.4.15、isNotNull

isNotNull(R column)
isNotNull(boolean condition, R column)

 
 
 
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字段 IS NOT NULL
例: isNotNull("name")—>name is not null

4.4.16、in

in(R column, Collection<?> value)
in(boolean condition, R column, Collection<?> value)

 
 
 
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字段 IN (value.get(0), value.get(1), …)
例: in("age",{1,2,3})—>age in (1,2,3)

in(R column, Object... values)
in(boolean condition, R column, Object... values)

 
 
 
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字段 IN (v0, v1, …)
例: in("age", 1, 2, 3)—>age in (1,2,3)

4.4.17、notIn

notIn(R column, Collection<?> value)
notIn(boolean condition, R column, Collection<?> value)

 
 
 
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字段 NOT IN (value.get(0), value.get(1), …)
例: notIn("age",{1,2,3})—>age not in (1,2,3)

notIn(R column, Object... values)
notIn(boolean condition, R column, Object... values)

 
 
 
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字段 NOT IN (v0, v1, …)
例: notIn("age", 1, 2, 3)—>age not in (1,2,3)

4.4.18、inSql

inSql(R column, String inValue)
inSql(boolean condition, R column, String inValue)

 
 
 
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字段 IN ( sql语句 )
例: inSql("age", "1,2,3,4,5,6")—>age in (1,2,3,4,5,6)
例: inSql("id", "select id from table where id < 3")—>id in (select id from table where id < 3)

4.4.19、notInSql

notInSql(R column, String inValue)
notInSql(boolean condition, R column, String inValue)

 
 
 
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字段 NOT IN ( sql语句 )
例: notInSql("age", "1,2,3,4,5,6")—>age not in (1,2,3,4,5,6)
例: notInSql("id", "select id from table where id < 3")—>id not in (select id from table where id < 3)

4.4.20、groupBy

groupBy(R... columns)
groupBy(boolean condition, R... columns)

 
 
 
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分组：GROUP BY 字段, …
例: groupBy("id", "name")—>group by id,name

4.4.21、orderByAsc

orderByAsc(R... columns)
orderByAsc(boolean condition, R... columns)

 
 
 
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排序：ORDER BY 字段, … ASC
例: orderByAsc("id", "name")—>order by id ASC,name ASC

4.4.22、orderByDesc

orderByDesc(R... columns)
orderByDesc(boolean condition, R... columns)

 
 
 
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排序：ORDER BY 字段, … DESC
例: orderByDesc("id", "name")—>order by id DESC,name DESC

4.4.23、orderBy

orderBy(boolean condition, boolean isAsc, R... columns)

 
 
 
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排序：ORDER BY 字段, …
例: orderBy(true, true, "id", "name")—>order by id ASC,name ASC

4.4.24、having

having(String sqlHaving, Object... params)
having(boolean condition, String sqlHaving, Object... params)

 
 
 
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HAVING ( sql语句 )
例: having("sum(age) > 10")—>having sum(age) > 10
例: having("sum(age) > {0}", 11)—>having sum(age) > 11

4.4.25、func

func(Consumer<Children> consumer)
func(boolean condition, Consumer<Children> consumer)

 
 
 
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func 方法(主要方便在出现if…else下调用不同方法能不断链)
例: func(i -> if(true) {i.eq("id", 1)} else {i.ne("id", 1)})

4.4.26、or

or()
or(boolean condition)

 
 
 
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拼接 OR

注意事项:

主动调用or表示紧接着下一个方法不是用and连接!(不调用or则默认为使用and连接)

例: eq("id",1).or().eq("name","老王")—>id = 1 or name = '老王'

or(Consumer<Param> consumer)
or(boolean condition, Consumer<Param> consumer)

 
 
 
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OR 嵌套
例: or(i -> i.eq("name", "李白").ne("status", "活着"))—>or (name = '李白' and status <> '活着')

4.4.27、and

and(Consumer<Param> consumer)
and(boolean condition, Consumer<Param> consumer)

 
 
 
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AND 嵌套
例: and(i -> i.eq("name", "李白").ne("status", "活着"))—>and (name = '李白' and status <> '活着')

4.4.28、nested

nested(Consumer<Param> consumer)
nested(boolean condition, Consumer<Param> consumer)

 
 
 
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正常嵌套不带 AND 或者 OR
例: nested(i -> i.eq("name", "李白").ne("status", "活着"))—>(name = '李白' and status <> '活着')

4.4.29、apply

apply(String applySql, Object... params)
apply(boolean condition, String applySql, Object... params)

 
 
 
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拼接 sql

注意事项:

该方法可用于数据库函数动态入参的params对应前面applySql内部的{index}部分，这样是不会有sql注入风险的，反之会有!

例: apply("id = 1")—>id = 1
例: apply("date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")—>date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")
例: apply("date_format(dateColumn,'%Y-%m-%d') = {0}", "2008-08-08")—>date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")

4.4.30、last

last(String lastSql)
last(boolean condition, String lastSql)

 
 
 
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无视优化规则直接拼接到 sql 的最后

注意事项:

只能调用一次，多次调用以最后一次为准，有sql注入的风险，请谨慎使用

例: last("limit 1")

4.4.31、exists

exists(String existsSql)
exists(boolean condition, String existsSql)

 
 
 
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拼接 EXISTS ( sql语句 )
例: exists("select id from table where age = 1")—>exists (select id from table where age = 1)

4.4.32、notExists

notExists(String notExistsSql)
notExists(boolean condition, String notExistsSql)

 
 
 
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拼接 NOT EXISTS ( sql语句 )
例: notExists("select id from table where age = 1")—>not exists (select id from table where age = 1)

第五章 MyBatis-Plus3代码生成器

5.1、数据导入

## 删除表
DROP TABLE IF EXISTS `tbl_user`;
## 创建表
CREATE TABLE `tbl_user` (
  `id` BIGINT(20) NOT NULL AUTO_INCREMENT COMMENT '主键ID',
  `name` VARCHAR(30) DEFAULT NULL COMMENT '姓名',
  `age` INT(11) DEFAULT NULL COMMENT '年龄',
  `email` VARCHAR(30) DEFAULT NULL COMMENT '邮箱',
  PRIMARY KEY (`id`)
) ENGINE=INNODB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8 COMMENT='用户';
## 导入数据
INSERT  INTO `tbl_user`(`id`,`name`,`age`,`email`) VALUES (1,'Jone',18,'test1@baomidou.com');
INSERT  INTO `tbl_user`(`id`,`name`,`age`,`email`) VALUES (2,'Jack',20,'test2@baomidou.com');
INSERT  INTO `tbl_user`(`id`,`name`,`age`,`email`) VALUES (3,'Tom',28,'test3@baomidou.com');
INSERT  INTO `tbl_user`(`id`,`name`,`age`,`email`) VALUES (4,'Sandy',21,'test4@baomidou.com');
INSERT  INTO `tbl_user`(`id`,`name`,`age`,`email`) VALUES (5,'Billie',24,'test5@baomidou.com');

 
 
 
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5.2、代码生成器简介

AutoGenerator 是 MyBatis-Plus 的代码生成器，通过 AutoGenerator 可以快速生成 Entity、Mapper、Mapper XML、Service、Controller 等各个模块的代码，极大的提升了开发效率。

5.3、代码生成器使用

5.3.1、添加依赖

pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>com.baomidou<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>mybatis-plus-boot-starter<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>3.4.0<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>mysql<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>mysql-connector-java<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>5.1.49<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>com.baomidou<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>mybatis-plus-generator<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>3.4.0<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>org.apache.velocity<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>velocity-engine-core<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>2.2<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>org.projectlombok<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>lombok<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>1.18.12<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>scope</span><span class="token punctuation">&gt;</span></span>provided<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>scope</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>

</dependencies>

<build>
    <!-- 插件管理 -->
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <version>2.5</version>
        </plugin>
    </plugins>
    <!-- 资源管理 -->
    <resources>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
                <include>**/*.conf</include>
            </includes>
            <filtering>false</filtering>
        </resource>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
                <include>**/*.conf</include>
            </includes>
            <filtering>false</filtering>
        </resource>
    </resources>
</build>

 
 
 
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5.3.2、添加配置

application.properties

#server
server.port=8080

#mysql
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/mp?useUnicode=true&characterEncoding=utf8
spring.datasource.username=root
spring.datasource.password=123456

#mybatis-plus
mybatis-plus.mapper-locations=classpath*????*/mapper/xml/*.xml
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

5.3.3、启动配置

MpDemoApplication.java

@SpringBootApplication
@MapperScan("com.caochenlei.mpdemo.mapper")
public class MpDemoApplication {
<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    SpringApplication<span class="token punctuation">.</span><span class="token function">run</span><span class="token punctuation">(</span>MpDemoApplication<span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">,</span> args<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}

5.3.4、代码生成

CodeGenerator.java

public class CodeGenerator {
<span class="token keyword">public</span> <span class="token keyword">static</span> String <span class="token function">scanner</span><span class="token punctuation">(</span>String tip<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    Scanner scanner <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Scanner</span><span class="token punctuation">(</span>System<span class="token punctuation">.</span>in<span class="token punctuation">)</span><span class="token punctuation">;</span>
    StringBuilder help <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">StringBuilder</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    help<span class="token punctuation">.</span><span class="token function">append</span><span class="token punctuation">(</span><span class="token string">"请输入"</span> <span class="token operator">+</span> tip <span class="token operator">+</span> <span class="token string">"："</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>help<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>scanner<span class="token punctuation">.</span><span class="token function">hasNext</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
        String ipt <span class="token operator">=</span> scanner<span class="token punctuation">.</span><span class="token function">next</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">if</span> <span class="token punctuation">(</span>StringUtils<span class="token punctuation">.</span><span class="token function">isNotBlank</span><span class="token punctuation">(</span>ipt<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
            <span class="token keyword">return</span> ipt<span class="token punctuation">;</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>
    <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">MybatisPlusException</span><span class="token punctuation">(</span><span class="token string">"请输入正确的"</span> <span class="token operator">+</span> tip <span class="token operator">+</span> <span class="token string">"！"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token comment">// 代码生成器</span>
    AutoGenerator mpg <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">AutoGenerator</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">// 全局配置</span>
    GlobalConfig gc <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">GlobalConfig</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    String projectPath <span class="token operator">=</span> System<span class="token punctuation">.</span><span class="token function">getProperty</span><span class="token punctuation">(</span><span class="token string">"user.dir"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    gc<span class="token punctuation">.</span><span class="token function">setOutputDir</span><span class="token punctuation">(</span>projectPath <span class="token operator">+</span> <span class="token string">"/src/main/java"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//设置代码生成路径</span>
    gc<span class="token punctuation">.</span><span class="token function">setFileOverride</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//是否覆盖以前文件</span>
    gc<span class="token punctuation">.</span><span class="token function">setOpen</span><span class="token punctuation">(</span><span class="token boolean">false</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//是否打开生成目录</span>
    gc<span class="token punctuation">.</span><span class="token function">setAuthor</span><span class="token punctuation">(</span><span class="token string">"caochenlei"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//设置项目作者名称</span>
    gc<span class="token punctuation">.</span><span class="token function">setIdType</span><span class="token punctuation">(</span>IdType<span class="token punctuation">.</span>AUTO<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//设置主键策略</span>
    gc<span class="token punctuation">.</span><span class="token function">setBaseResultMap</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//生成基本ResultMap</span>
    gc<span class="token punctuation">.</span><span class="token function">setBaseColumnList</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//生成基本ColumnList</span>
    gc<span class="token punctuation">.</span><span class="token function">setServiceName</span><span class="token punctuation">(</span><span class="token string">"%sService"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token comment">//去掉服务默认前缀</span>
    mpg<span class="token punctuation">.</span><span class="token function">setGlobalConfig</span><span class="token punctuation">(</span>gc<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">// 数据源配置</span>
    DataSourceConfig dsc <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">DataSourceConfig</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    dsc<span class="token punctuation">.</span><span class="token function">setUrl</span><span class="token punctuation">(</span><span class="token string">"jdbc:mysql://localhost:3306/mp?useSSL=false&amp;useUnicode=true&amp;characterEncoding=utf8"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    dsc<span class="token punctuation">.</span><span class="token function">setDriverName</span><span class="token punctuation">(</span><span class="token string">"com.mysql.jdbc.Driver"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    dsc<span class="token punctuation">.</span><span class="token function">setUsername</span><span class="token punctuation">(</span><span class="token string">"root"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    dsc<span class="token punctuation">.</span><span class="token function">setPassword</span><span class="token punctuation">(</span><span class="token string">"123456"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    mpg<span class="token punctuation">.</span><span class="token function">setDataSource</span><span class="token punctuation">(</span>dsc<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">// 包配置</span>
    PackageConfig pc <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PackageConfig</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    pc<span class="token punctuation">.</span><span class="token function">setParent</span><span class="token punctuation">(</span><span class="token string">"com.caochenlei.mpdemo"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    pc<span class="token punctuation">.</span><span class="token function">setMapper</span><span class="token punctuation">(</span><span class="token string">"mapper"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    pc<span class="token punctuation">.</span><span class="token function">setXml</span><span class="token punctuation">(</span><span class="token string">"mapper.xml"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    pc<span class="token punctuation">.</span><span class="token function">setEntity</span><span class="token punctuation">(</span><span class="token string">"pojo"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    pc<span class="token punctuation">.</span><span class="token function">setService</span><span class="token punctuation">(</span><span class="token string">"service"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    pc<span class="token punctuation">.</span><span class="token function">setServiceImpl</span><span class="token punctuation">(</span><span class="token string">"service.impl"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    pc<span class="token punctuation">.</span><span class="token function">setController</span><span class="token punctuation">(</span><span class="token string">"controller"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    mpg<span class="token punctuation">.</span><span class="token function">setPackageInfo</span><span class="token punctuation">(</span>pc<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">// 策略配置</span>
    StrategyConfig sc <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">StrategyConfig</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    sc<span class="token punctuation">.</span><span class="token function">setNaming</span><span class="token punctuation">(</span>NamingStrategy<span class="token punctuation">.</span>underline_to_camel<span class="token punctuation">)</span><span class="token punctuation">;</span>
    sc<span class="token punctuation">.</span><span class="token function">setColumnNaming</span><span class="token punctuation">(</span>NamingStrategy<span class="token punctuation">.</span>underline_to_camel<span class="token punctuation">)</span><span class="token punctuation">;</span>
    sc<span class="token punctuation">.</span><span class="token function">setEntityLombokModel</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    sc<span class="token punctuation">.</span><span class="token function">setRestControllerStyle</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    sc<span class="token punctuation">.</span><span class="token function">setControllerMappingHyphenStyle</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    sc<span class="token punctuation">.</span><span class="token function">setTablePrefix</span><span class="token punctuation">(</span><span class="token string">"tbl_"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    sc<span class="token punctuation">.</span><span class="token function">setInclude</span><span class="token punctuation">(</span><span class="token function">scanner</span><span class="token punctuation">(</span><span class="token string">"表名，多个英文逗号分割"</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">split</span><span class="token punctuation">(</span><span class="token string">","</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    mpg<span class="token punctuation">.</span><span class="token function">setStrategy</span><span class="token punctuation">(</span>sc<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">// 生成代码</span>
    mpg<span class="token punctuation">.</span><span class="token function">execute</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}

5.3.5、工程结构

5.3.6、添加代码

UserController.java

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;
<span class="token annotation punctuation">@RequestMapping</span><span class="token punctuation">(</span><span class="token string">"/all"</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> List<span class="token generics function"><span class="token punctuation">&lt;</span>User<span class="token punctuation">&gt;</span></span> <span class="token function">getAll</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    <span class="token keyword">return</span> userService<span class="token punctuation">.</span><span class="token function">list</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}

5.3.7、启动运行

MpDemoApplication.java 中运行主方法以此来启动整个工程

@SpringBootApplication
@MapperScan("com.caochenlei.mpdemo.mapper")
public class MpDemoApplication {
<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
    SpringApplication<span class="token punctuation">.</span><span class="token function">run</span><span class="token punctuation">(</span>MpDemoApplication<span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">,</span> args<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}

5.3.8、测试方法

使用浏览器打开：http://localhost:8080/user/all

5.3.9、温馨提示

需要Lombok插件支持，只需要安装一下就可以了，打开 IDEA，进入 File -> Settings -> Plugins，安装完成后重启

5.4、代码生成器方法

通用 Service CRUD 封装 IService 接口，进一步封装 CRUD 采用 get 查询单行 remove 删除 list 查询集合 page 分页 前缀命名方式区分 Mapper 层避免混淆，泛型 T 为任意实体对象，建议如果存在自定义通用 Service 方法的可能，请创建自己的 IBaseService 继承 Mybatis-Plus 提供的基类，对象 Wrapper 为条件构造器。

5.4.1、save

// 插入一条记录（选择字段，策略插入）
boolean save(T entity);
// 插入（批量）
boolean saveBatch(Collection<T> entityList);
// 插入（批量）
boolean saveBatch(Collection<T> entityList, int batchSize);

 
 
 
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参数说明：

类型	参数名	描述
T	entity	实体对象
Collection<T>	entityList	实体对象集合
int	batchSize	插入批次数量

5.4.2、saveOrUpdate

// TableId 注解存在更新记录，否插入一条记录
boolean saveOrUpdate(T entity);
// 根据updateWrapper尝试更新，否继续执行saveOrUpdate(T)方法
boolean saveOrUpdate(T entity, Wrapper<T> updateWrapper);
// 批量修改插入
boolean saveOrUpdateBatch(Collection<T> entityList);
// 批量修改插入
boolean saveOrUpdateBatch(Collection<T> entityList, int batchSize);

 
 
 
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参数说明：

类型	参数名	描述
T	entity	实体对象
Wrapper<T>	updateWrapper	实体对象封装操作类 UpdateWrapper
Collection<T>	entityList	实体对象集合
int	batchSize	插入批次数量

5.4.3、remove

// 根据 entity 条件，删除记录
boolean remove(Wrapper<T> queryWrapper);
// 根据 ID 删除
boolean removeById(Serializable id);
// 根据 columnMap 条件，删除记录
boolean removeByMap(Map<String, Object> columnMap);
// 删除（根据ID 批量删除）
boolean removeByIds(Collection<? extends Serializable> idList);

 
 
 
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参数说明：

类型	参数名	描述
Wrapper<T>	queryWrapper	实体包装类 QueryWrapper
Serializable	id	主键ID
Map<String, Object>	columnMap	表字段 map 对象
Collection<? extends Serializable>	idList	主键ID列表

5.4.4、update

// 根据 UpdateWrapper 条件，更新记录 需要设置sqlset
boolean update(Wrapper<T> updateWrapper);
// 根据 whereEntity 条件，更新记录
boolean update(T entity, Wrapper<T> updateWrapper);
// 根据 ID 选择修改
boolean updateById(T entity);
// 根据ID 批量更新
boolean updateBatchById(Collection<T> entityList);
// 根据ID 批量更新
boolean updateBatchById(Collection<T> entityList, int batchSize);

 
 
 
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参数说明：

类型	参数名	描述
Wrapper<T>	updateWrapper	实体对象封装操作类 UpdateWrapper
T	entity	实体对象
Collection<T>	entityList	实体对象集合
int	batchSize	更新批次数量

5.4.5、get

// 根据 ID 查询
T getById(Serializable id);
// 根据 Wrapper，查询一条记录。结果集，如果是多个会抛出异常，随机取一条加上限制条件 wrapper.last("LIMIT 1")
T getOne(Wrapper<T> queryWrapper);
// 根据 Wrapper，查询一条记录
T getOne(Wrapper<T> queryWrapper, boolean throwEx);
// 根据 Wrapper，查询一条记录
Map<String, Object> getMap(Wrapper<T> queryWrapper);
// 根据 Wrapper，查询一条记录
<V> V getObj(Wrapper<T> queryWrapper, Function<? super Object, V> mapper);

 
 
 
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参数说明：

类型	参数名	描述
Serializable	id	主键ID
Wrapper<T>	queryWrapper	实体对象封装操作类 QueryWrapper
boolean	throwEx	有多个 result 是否抛出异常
T	entity	实体对象
Function<? super Object, V>	mapper	转换函数

5.4.6、list

// 查询所有
List<T> list();
// 查询列表
List<T> list(Wrapper<T> queryWrapper);
// 查询（根据ID 批量查询）
Collection<T> listByIds(Collection<? extends Serializable> idList);
// 查询（根据 columnMap 条件）
Collection<T> listByMap(Map<String, Object> columnMap);
// 查询所有列表
List<Map<String, Object>> listMaps();
// 查询列表
List<Map<String, Object>> listMaps(Wrapper<T> queryWrapper);
// 查询全部记录
List<Object> listObjs();
// 查询全部记录
<V> List<V> listObjs(Function<? super Object, V> mapper);
// 根据 Wrapper 条件，查询全部记录
List<Object> listObjs