Mybatis分页

一、为什么要分页？

• 减少数据处理

二、SQL分页语句limit

-- 语法：select * from mybatis.user limit startIndex,pageSize;
select * from mybatis.user limit 0,2;
select * from mybatis.user limit 3; #[0,3]

三、使用Mybatis实现分页

1. 接口

public interface UserMapper {
    List<User> getUserListBylimit(Map<String ,Integer> map);
}

2. Mapper.xml

<select id="getUserListBylimit" parameterType="map" resultType="user">
    select * from mybatis.user limit #{startIndex},#{pageSize}
</select>

3. 测试

@Test
public void Test2(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    UserMapper mapper = sqlSession.getMapper(UserMapper.class);

    Map<String, Integer> map = new HashMap<>();
    map.put("startIndex",1);
    map.put("pageSize",2);

    List<User> userListBylimit = mapper.getUserListBylimit(map);
    System.out.println(userListBylimit);
    sqlSession.close();
}

四、通过RowBounds实现分页

不再使用SQL实现分页

1. 接口

public interface UserMapper {
    List<User> getUserListByRowBounds();
}

2. Mapper.xml

<select id="getUserListByRowBounds" resultType="user">
    select * from mybatis.user
</select>

3. 测试

@Test
public void Test3(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    UserMapper mapper = sqlSession.getMapper(UserMapper.class);

    RowBounds rowBounds = new RowBounds(1, 2);
    List<User> userList = sqlSession.selectList("com.nichu.dao.UserMapper.getUserListByRowBounds", null, rowBounds);
    System.out.println(userList);
    sqlSession.close();
}