mybatis learning - implement paging

First look paging sql statement:

SELEC * FROM 表名 LIMIT startIndex，pageSize

tips：

　　* StartIndex: starting position (from which the element start page)

　　* PageSize: how many elements per page

E.g:

select * from user limit 0,2: query the user table all the elements, the starting position is the first zero element, two elements per page

select * from user limit 3: query the user table all the elements, the starting position is the first zero elements, the elements per page 3

 

Use mabatis implement paging:

(1) defines the interface

package com.kuang.dao;

import com.kuang.pojo.User;

import java.util.List;
import java.util.Map;

public interface UserMapper {

    List<User> getUserByLimit(Map<String ,Object> map);

}

(2) mapping file to write

<?xml version="1.0" encoding="UTF-8" ?>
        <!DOCTYPE mapper
                PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
                "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.kuang.dao.UserMapper">
    
    <select id="getUserByLimit" resultMap="user" parameterType="map">
        SELECT * FROM mybatis.user LIMIT #{startIndex},#{pageSize}
    </select>

</mapper>

(3) Writing Test Methods

    @Test
    public void getUserByLimit(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        HashMap<String, Object> map = new HashMap<String, Object>();
        map.put("startIndex",0);
        map.put("pageSize",2);
        List<User> userList = mapper.getUserByLimit(map);
        for (User user : userList) {
            System.out.println(user);
        }
        sqlSession.close();
    }