Mybatis笔记7--limit分页

7、分页

为什么要分页？

减少数据的处理量

1、使用Limit分页

语法：SELECT * from user limit startIndes,pageSize; SELECT * from user limit 3; #[0,n]

使用Mybatis实现分页，核心SQL

接口

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

Mapper.xml

<!--分页查询--> <select id="getUserByLimit" parameterType="map" resultMap="UserMap"> select * from mybatis.user limit #{startIndes},#{pageSize} </select>

测试

//分页查询 @Test public void getUserByLimit(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); HashMap<String, Integer> map = new HashMap<String, Integer>(); map.put("startIndes",0); map.put("pageSize",3); List<User> userList = mapper.getUserByLimit(map); for (User user : userList) { System.out.println(user); } sqlSession.close(); }

2、RowBouds分页

不再使用SQL实现分页

接口

//分页查询2 List<User> getUserByRowBounds();

mapper.xml

<!--分页查询2--> <select id="getUserByRowBounds" resultMap="UserMap"> select * from mybatis.user </select>

测试

//分页查询2 @Test public void getUserByRowBounds(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); //RowBounds实现 RowBounds rowBounds = new RowBounds(1,2); //通过java代码实现分页 List<User> list = sqlSession.selectList("com.cfeng.dao.UserMapper.getUserByRowBounds", null, rowBounds); for (User user : list) { System.out.println(user); } sqlSession.close(); }

3、分页插件（ Mybatis-PageHelper）https://pagehelper.github.io/

了解即可！