关于Hibernate+Mysql8.0的一些注意事项

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我是靠谱客的博主无聊音响，最近开发中收集的这篇文章主要介绍关于Hibernate+Mysql8.0的一些注意事项，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

<!--
~ Hibernate, Relational Persistence for Idiomatic Java
~
~ License: GNU Lesser General Public License (LGPL), version 2.1 or later.
~ See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
-->
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/myy?useSSL=false&amp;serverTimezone=UTC</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<!-- 设置方言 -->
<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
<!-- 注册当前session上下文：保证同一线程中获得的session是同一个session
<property name="hibernate.current_session_context_class">thread</property>
-->
<!-- 自动建表 -->
<property name="hibernate.hbm2ddl.auto">update</property>
<!-- 显示SQL -->
<property name="hibernate.show_sql">true</property>
<!-- 格式化SQL -->
<property name="hibernate.format_sql">true</property>
<!--指定关联的 。hbm。xml文件 -->
<mapping resource="com/pyq/hibernate/helloworld/News.hbm.xml"></mapping>
</session-factory>
</hibernate-configuration>

hibernate.cfg.xml配置在src目录下注意驱动，方言和url一定要按照上面的来写，这里就不说明原因了，已经与百度密切合作:

www.baidu.com

package com.pyq.hibernate.helloworld;
import java.sql.Date;
public class News {
private Integer id;
private String title;
private String author;
private Date date;
public News() {
super();
// TODO Auto-generated constructor stub
}
public News(Integer id, String title, String author, Date date) {
this.id = id;
this.title = title;
this.author = author;
this.date = date;
}
public News( String title, String author, Date date) {
this.title = title;
this.author = author;
this.date = date;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
}

News类

<mapping resource="com/pyq/hibernate/helloworld/News.hbm.xml"></mapping>在hibernate.cfg.xml关联

<?xml version="1.0" encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/dtd/hibernate-mapping-3.0.dtd" >
<hibernate-mapping>
<class name="com.pyq.hibernate.helloworld.News" table="News">
<id name="id" type="java.lang.Integer">
<column name="ID"></column>
<generator class="native"/>
</id>
<property name="title"
type="java.lang.String" >
<column name="TITLE"></column>
</property>
<property name="author"
type="java.lang.String" >
<column name="AUTHOR"></column>
</property>
<property name="date"
type="java.sql.Date" >
<column name="DATE"></column>
</property>
</class>
</hibernate-mapping>

News中的属性与数据库字段对应，我这里启动的是自增的ID ：<generator class="native"/>

注意你的mysql8.0中ID需要设置为主键且自增，推荐大家使用Navicat Premium来开发

package com.pyq.hibernate.helloworld;
import java.sql.Date;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
public class Test {
public static void main(String[] args){
//创建一个会话工厂对象SessionFactory
SessionFactory sessionFactory = null;
//创建Con对象：对应hibernate的基本配置信息和对象关系映射
Configuration config = new Configuration().configure();
//4.0之前这样创建
//sessionFactory = config.buildSessionFactory();
//4.x创建一个SessionFactoryRegistry对象hibernate的任何配置和服务都需要在该对象中注册后才有用
StandardServiceRegistry standardRegistry = new
StandardServiceRegistryBuilder().configure().build();
sessionFactory
= config.buildSessionFactory(standardRegistry);
//创建并打开会话
Session session =sessionFactory.openSession();
//开启事务
org.hibernate.Transaction transaction = session.beginTransaction();
//执行保存操作
News news = new News("Java", "pyq", new Date(new java.util.Date().getTime()));
session.save(news);
//提交事务
transaction.commit();
//关闭session
session.close();
//关闭sessionfactory
sessionFactory.close();
}
}

最后是测试类，我这里给我的News类重载了一个构造方法，即没有放入ID，因为我选择的是ID自增长，还有一点在hibernate.cfg.xml中<property name="hibernate.hbm2ddl.auto">update</property>我也自动建立了表，你不用去数据库建News表，他会自动生成。最后启动工程hibernate.cfg.xml中<property name="hibernate.show_sql">true</property>会在控制台打印建表和插入sql