MybatisPlus生成器ServiceImpl类详解

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

1. getBaseMapper()
2. getEntityClass()
3. saveBatch()
4. saveOrUpdate()
5. saveOrUpdateBatch()
6. updateBatchById()
7. getOne()
8. getMap()
9. getObj()

ServiceImpl类各属性的作用

1. log：打印日志
2. baseMapper：实现了许多的SQL操作
3. entityClass：实体类
4. 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：

1. int insert(T entity);：插入记录
2. int deleteById(Serializable id);：通过id删除指定记录
3. int deleteByMap(Map<String, Object> columnMap)：通过Map集合添加删除指定记录
4. int delete(@Param(Constants.WRAPPER) Wrapper queryWrapper)：通过添加构造器删除指定记录
5. int deleteBatchIds(Collection<? extends Serializable> idList)：通过List集合批量删除记录
6. int updateById(T entity)：根据id修改指定记录
7. int update(T entity, Wrapper updateWrapper)：根据条件构造器
8. T selectById(Serializable id)：根据id查询指定记录
9. List selectBatchIds(Collection<? extends Serializable> idList)：根据List集合批量查询记录
10. List selectByMap(Map<String, Object> columnMap)：根据Map集合查询记录
11. T selectOne(Wrapper queryWrapper)：根据条件构造器查询一条记录
12. Integer selectCount(Wrapper queryWrapper)：根据条件构造器查询记录总数
13. List selectList(Wrapper queryWrapper)：根据条件构造器查询全部记录
14. List<Map<String, Object>> selectMaps(Wrapper queryWrapper)：根据条件构造器查询全部记录
15. ist selectObjs(Wrapper queryWrapper)：根据条件构造器查询全部记录
16. <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）
17. <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

1. getEntity()：实体对象（子类实现）
2. getSqlSelectgetSqlSet()：
3. getSqlComment()：
4. getSqlFirst()：
5. getExpression()：获取 MergeSegments
6. getCustomSqlSegment()：获取自定义SQL 简化自定义XML复杂情况
7. isEmptyOfWhere()：查询条件为空(包含entity)
8. nonEmptyOfWhere()：查询条件不为空(包含entity)
9. isEmptyOfNormal()：查询条件为空(不包含entity)
10. nonEmptyOfNormal()：查询条件为空(不包含entity)
11. nonEmptyOfEntity()：深层实体判断属性
12. fieldStrategyMatch()：根据实体FieldStrategy属性来决定判断逻辑
13. isEmptyOfEntity()：深层实体判断属性
14. getTargetSql()：获取格式化后的执行sql
15. 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 {}

在ServiceImpl中已经注入了Mapper对象： protected M baseMapper；因此XXXServiceImpl只要继承了这个原生的ServiceImpl，这个M实体Dao就已经注入了进来，不需要重新注入。