MybatisPlus生成器ServiceImpl类详解

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我是靠谱客的博主追寻小馒头，最近开发中收集的这篇文章主要介绍MybatisPlus生成器ServiceImpl类详解，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

ServiceImpl类是我们进行SQL操作中非常重要的一个类，通过MybatisPlus生成的各个实体类的XXXImpl都会继承ServiceImpl类那里继承全部的方法，那么ServiceImpl类中有哪些方法呢？如下介绍：


/**
 * IService 实现类（ 泛型：M 是 mapper 对象，T 是实体 ）
 *
 * @author hubin
 * @since 2018-06-23
 */
@SuppressWarnings("unchecked")
public class ServiceImpl<M extends BaseMapper<T>, T> implements IService<T> {

    protected Log log = LogFactory.getLog(getClass());

    @Autowired
    protected M baseMapper;

    @Override
    public M getBaseMapper() {
        return baseMapper;
    }

    protected Class<T> entityClass = currentModelClass();

    @Override
    public Class<T> getEntityClass() {
        return entityClass;
    }

    protected Class<T> mapperClass = currentMapperClass();

    /**
     * 判断数据库操作是否成功
     *
     * @param result 数据库操作返回影响条数
     * @return boolean
     * @deprecated 3.3.1
     */
    @Deprecated
    protected boolean retBool(Integer result) {
        return SqlHelper.retBool(result);
    }

    protected Class<T> currentMapperClass() {
        return (Class<T>) ReflectionKit.getSuperClassGenericType(getClass(), 0);
    }

    protected Class<T> currentModelClass() {
        return (Class<T>) ReflectionKit.getSuperClassGenericType(getClass(), 1);
    }

    /**
     * 批量操作 SqlSession
     *
     * @deprecated 3.3.0
     */
    @Deprecated
    protected SqlSession sqlSessionBatch() {
        return SqlHelper.sqlSessionBatch(entityClass);
    }

    /**
     * 释放sqlSession
     *
     * @param sqlSession session
     * @deprecated 3.3.0
     */
    @Deprecated
    protected void closeSqlSession(SqlSession sqlSession) {
        SqlSessionUtils.closeSqlSession(sqlSession, GlobalConfigUtils.currentSessionFactory(entityClass));
    }

    /**
     * 获取 SqlStatement
     *
     * @param sqlMethod ignore
     * @return ignore
     * @see #getSqlStatement(SqlMethod)
     * @deprecated 3.4.0
     */
    @Deprecated
    protected String sqlStatement(SqlMethod sqlMethod) {
        return SqlHelper.table(entityClass).getSqlStatement(sqlMethod.getMethod());
    }

    /**
     * 批量插入
     *
     * @param entityList ignore
     * @param batchSize  ignore
     * @return ignore
     */
    @Transactional(rollbackFor = Exception.class)
    @Override
    public boolean saveBatch(Collection<T> entityList, int batchSize) {
        String sqlStatement = getSqlStatement(SqlMethod.INSERT_ONE);
        return executeBatch(entityList, batchSize, (sqlSession, entity) -> sqlSession.insert(sqlStatement, entity));
    }

    /**
     * 获取mapperStatementId
     *
     * @param sqlMethod 方法名
     * @return 命名id
     * @since 3.4.0
     */
    protected String getSqlStatement(SqlMethod sqlMethod) {
        return SqlHelper.getSqlStatement(mapperClass, sqlMethod);
    }

    /**
     * TableId 注解存在更新记录，否插入一条记录
     *
     * @param entity 实体对象
     * @return boolean
     */
    @Transactional(rollbackFor = Exception.class)
    @Override
    public boolean saveOrUpdate(T entity) {
        if (null != entity) {
            TableInfo tableInfo = TableInfoHelper.getTableInfo(this.entityClass);
            Assert.notNull(tableInfo, "error: can not execute. because can not find cache of TableInfo for entity!");
            String keyProperty = tableInfo.getKeyProperty();
            Assert.notEmpty(keyProperty, "error: can not execute. because can not find column for id from entity!");
            Object idVal = ReflectionKit.getFieldValue(entity, tableInfo.getKeyProperty());
            return StringUtils.checkValNull(idVal) || Objects.isNull(getById((Serializable) idVal)) ? save(entity) : updateById(entity);
        }
        return false;
    }

    @Transactional(rollbackFor = Exception.class)
    @Override
    public boolean saveOrUpdateBatch(Collection<T> entityList, int batchSize) {
        TableInfo tableInfo = TableInfoHelper.getTableInfo(entityClass);
        Assert.notNull(tableInfo, "error: can not execute. because can not find cache of TableInfo for entity!");
        String keyProperty = tableInfo.getKeyProperty();
        Assert.notEmpty(keyProperty, "error: can not execute. because can not find column for id from entity!");
        return SqlHelper.saveOrUpdateBatch(this.entityClass, this.mapperClass, this.log, entityList, batchSize, (sqlSession, entity) -> {
            Object idVal = ReflectionKit.getFieldValue(entity, keyProperty);
            return StringUtils.checkValNull(idVal)
                || CollectionUtils.isEmpty(sqlSession.selectList(getSqlStatement(SqlMethod.SELECT_BY_ID), entity));
        }, (sqlSession, entity) -> {
            MapperMethod.ParamMap<T> param = new MapperMethod.ParamMap<>();
            param.put(Constants.ENTITY, entity);
            sqlSession.update(getSqlStatement(SqlMethod.UPDATE_BY_ID), param);
        });
    }

    @Transactional(rollbackFor = Exception.class)
    @Override
    public boolean updateBatchById(Collection<T> entityList, int batchSize) {
        String sqlStatement = getSqlStatement(SqlMethod.UPDATE_BY_ID);
        return executeBatch(entityList, batchSize, (sqlSession, entity) -> {
            MapperMethod.ParamMap<T> param = new MapperMethod.ParamMap<>();
            param.put(Constants.ENTITY, entity);
            sqlSession.update(sqlStatement, param);
        });
    }

    @Override
    public T getOne(Wrapper<T> queryWrapper, boolean throwEx) {
        if (throwEx) {
            return baseMapper.selectOne(queryWrapper);
        }
        return SqlHelper.getObject(log, baseMapper.selectList(queryWrapper));
    }

    @Override
    public Map<String, Object> getMap(Wrapper<T> queryWrapper) {
        return SqlHelper.getObject(log, baseMapper.selectMaps(queryWrapper));
    }

    @Override
    public <V> V getObj(Wrapper<T> queryWrapper, Function<? super Object, V> mapper) {
        return SqlHelper.getObject(log, listObjs(queryWrapper, mapper));
    }

    /**
     * 执行批量操作
     *
     * @param consumer consumer
     * @since 3.3.0
     * @deprecated 3.3.1 后面我打算移除掉 {@link #executeBatch(Collection, int, BiConsumer)} }.
     */
    @Deprecated
    protected boolean executeBatch(Consumer<SqlSession> consumer) {
        return SqlHelper.executeBatch(this.entityClass, this.log, consumer);
    }

    /**
     * 执行批量操作
     *
     * @param list      数据集合
     * @param batchSize 批量大小
     * @param consumer  执行方法
     * @param <E>       泛型
     * @return 操作结果
     * @since 3.3.1
     */
    protected <E> boolean executeBatch(Collection<E> list, int batchSize, BiConsumer<SqlSession, E> consumer) {
        return SqlHelper.executeBatch(this.entityClass, this.log, list, batchSize, consumer);
    }

    /**
     * 执行批量操作（默认批次提交数量{@link IService#DEFAULT_BATCH_SIZE}）
     *
     * @param list     数据集合
     * @param consumer 执行方法
     * @param <E>      泛型
     * @return 操作结果
     * @since 3.3.1
     */
    protected <E> boolean executeBatch(Collection<E> list, BiConsumer<SqlSession, E> consumer) {
        return executeBatch(list, DEFAULT_BATCH_SIZE, consumer);
    }

}

ServiceImpl类各方法（未过期）的作用

getBaseMapper()
getEntityClass()
saveBatch()
saveOrUpdate()
saveOrUpdateBatch()
updateBatchById()
getOne()
getMap()
getObj()

ServiceImpl类各属性的作用

log：打印日志
baseMapper：实现了许多的SQL操作
entityClass：实体类
mapperClass：映射类

BaseMapper类中各方法

ServiceImpl类中有这个类的成员变量，因此通过ServiceImpl这个类便能够操作如下方法：

int insert(T entity);：插入记录
int deleteById(Serializable id);：通过id删除指定记录
int deleteByMap(Map<String, Object> columnMap)：通过Map集合添加删除指定记录
int delete(@Param(Constants.WRAPPER) Wrapper queryWrapper)：通过添加构造器删除指定记录
int deleteBatchIds(Collection<? extends Serializable> idList)：通过List集合批量删除记录
int updateById(T entity)：根据id修改指定记录
int update(T entity, Wrapper updateWrapper)：根据条件构造器
T selectById(Serializable id)：根据id查询指定记录
List selectBatchIds(Collection<? extends Serializable> idList)：根据List集合批量查询记录
List selectByMap(Map<String, Object> columnMap)：根据Map集合查询记录
T selectOne(Wrapper queryWrapper)：根据条件构造器查询一条记录
Integer selectCount(Wrapper queryWrapper)：根据条件构造器查询记录总数
List selectList(Wrapper queryWrapper)：根据条件构造器查询全部记录
List<Map<String, Object>> selectMaps(Wrapper queryWrapper)：根据条件构造器查询全部记录
ist selectObjs(Wrapper queryWrapper)：根据条件构造器查询全部记录
<E extends IPage> E selectPage(E page, Wrapper queryWrapper)：根据条件构造器查询全部记录（并翻页）
<E extends IPage<Map<String, Object>>> E selectMapsPage(E page, Wrapper queryWrapper)：根据条件构造器查询全部记录（并翻页）

Wrapper类各方法

getEntity()：实体对象（子类实现）
getSqlSelectgetSqlSet()：
getSqlComment()：
getSqlFirst()：
getExpression()：获取 MergeSegments
getCustomSqlSegment()：获取自定义SQL 简化自定义XML复杂情况
isEmptyOfWhere()：查询条件为空(包含entity)
nonEmptyOfWhere()：查询条件不为空(包含entity)
isEmptyOfNormal()：查询条件为空(不包含entity)
nonEmptyOfNormal()：查询条件为空(不包含entity)
nonEmptyOfEntity()：深层实体判断属性
fieldStrategyMatch()：根据实体FieldStrategy属性来决定判断逻辑
isEmptyOfEntity()：深层实体判断属性
getTargetSql()：获取格式化后的执行sql
clear()：条件清空

实例说明

public class ServiceImpl<M extends BaseMapper<T>, T> implements IService<T> {}

public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {}