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。
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