mybatis-plus批量删除_Mybatis Plus mapper的多种姿势删除数据
Mybatis Plus的删除操作内置了4种方法，我们来演示一下Mybatis Plus的删除操作。
Mybatis Plus mapper的删除操作
1、根据主键ID删除指定单条数据
方法：
int deleteById(Serializable id);代码：
@Test public void testDeleteById() { System.out.println(("----- deleteById method test ------")); List userList = userMapper.selectList(null); System.out.println("-----删除前数据:"); userList.forEach(System.out::println); userMapper.deleteById(5L); System.out.println("-----删除后剩余数据:"); List userList2 = userMapper.selectList(null); userList2.forEach(System.out::println); }前面已经输出了较多sql，我们这里简洁一些，只输出打印的数据
-----删除前数据:User(id=1, name=Jone, age=18, [email protected])User(id=2, name=Jack, age=20, [email protected])User(id=3, name=Tom, age=28, [email protected])User(id=4, name=Sandy, age=21, [email protected])User(id=5, name=Billie, age=24, [email protected])-----删除后剩余数据:User(id=1, name=Jone, age=18, [email protected])User(id=2, name=Jack, age=20, [email protected])User(id=3, name=Tom, age=28, [email protected])User(id=4, name=Sandy, age=21, [email protected])2、基于map中设置的key-value，删除一条或多条数据
基于map的删除，可以设置多个列作为条件，被匹配的数据都将被删除。
方法：
int deleteByMap(@Param(Constants.COLUMN_MAP) Map columnMap);代码：
@Test public void testDeleteByMap() { System.out.println(("----- deleteByMap method test ------")); List userList = userMapper.selectList(null); System.out.println("-----删除前数据:"); userList.forEach(System.out::println); Map columnMap = new HashMap<>(); columnMap.put("Name","Tom"); userMapper.deleteByMap(columnMap); System.out.println("-----删除后剩余数据:"); List userList2 = userMapper.selectList(null); userList2.forEach(System.out::println); }输出：
-----删除前数据:User(id=1, name=Jone, age=18, [email protected])User(id=2, name=Jack, age=20, [email protected])User(id=3, name=Tom, age=28, [email protected])User(id=4, name=Sandy, age=21, [email protected])User(id=5, name=Billie, age=24, [email protected])-----删除后剩余数据:User(id=1, name=Jone, age=18, [email protected])User(id=2, name=Jack, age=20, [email protected])User(id=4, name=Sandy, age=21, [email protected])User(id=5, name=Billie, age=24, [email protected])3、基于一个实体作为条件，删除一条或多条数据
方法：
int delete(@Param(Constants.WRAPPER) Wrapper wrapper);如果方法的参数设置为null，那么相当于全表删除
代码：
输出结果：
-----删除前数据:User(id=1, name=Jone, age=18, [email protected])User(id=2, name=Jack, age=20, [email protected])User(id=3, name=Tom, age=28, [email protected])User(id=4, name=Sandy, age=21, [email protected])User(id=5, name=Billie, age=24, [email protected])==> Preparing: DELETE FROM user ==> Parameters: <== Updates: 5-----删除后剩余数据:==> Preparing: SELECT id,name,age,email FROM user ==> Parameters: <== Total: 0我们从输出的日志看出：
==> Preparing: DELETE FROM user ==> Parameters: <== Updates: 5sql是全表删除。
如果方法设置了实体作为参数，那就按照实体匹配，删除对应数据。
4、根据主键ID集合，批量删除数据
方法：
int deleteBatchIds(@Param(Constants.COLLECTION) Collection extends Serializable> idList);代码：
@Test public void testDeleteBatchIds() { System.out.println(("----- deleteBatchIds method test ------")); List userList = userMapper.selectList(null); System.out.println("-----删除前数据:"); userList.forEach(System.out::println); List list = new ArrayList(); list.add(4L); list.add(5L); userMapper.deleteBatchIds(list); System.out.println("-----删除后剩余数据:"); List userList2 = userMapper.selectList(null); userList2.forEach(System.out::println); }输出：
-----删除前数据:User(id=1, name=Jone, age=18, [email protected])User(id=2, name=Jack, age=20, [email protected])User(id=3, name=Tom, age=28, [email protected])User(id=4, name=Sandy, age=21, [email protected])User(id=5, name=Billie, age=24, [email protected])==> Preparing: DELETE FROM user WHERE id IN ( ? , ? ) ==> Parameters: 4(Long), 5(Long)<== Updates: 2-----删除后剩余数据:==> Preparing: SELECT id,name,age,email FROM user ==> Parameters: <== Columns: ID, NAME, AGE, EMAIL<== Row: 1, Jone, 18, [email protected]<== Row: 2, Jack, 20, [email protected]<== Row: 3, Tom, 28, [email protected]<== Total: 3User(id=1, name=Jone, age=18, [email protected])User(id=2, name=Jack, age=20, [email protected])User(id=3, name=Tom, age=28, [email protected])