MyBatis(分页)

思考：为什么要分页？

• 减少数据的分量

使用Limit分页

语法：SELECT * from   user limit   startIndex,pageSize;（https://www.cnblogs.com/cai170221/p/7122289.html mysqlLimit语法点的学习。）
mysqlbug查看：https://www.cnblogs.com/cai170221/p/7122289.html

select * from user limit 3; #[0,n]

使用Mybatis实现分页（核心SQL）

1.接口

 //分页
    List<User> getUserByLimit(Map<String,Integer> map);

2.Mapper.XML

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

3.测试

  @Test
    public void getUserByLimit(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        HashMap<String, Integer> map = new HashMap<String, Integer>();
        map.put("startIndex", 1 );
        map.put("pageSize", 2);

        List<User> userlist = mapper.getUserByLimit(map);
        for (User user : userlist) {
            System.out.println(user);
        }
        sqlSession.close();
    }