What are the several ways of paging in mybatis?

MyBatis commonly used paging methods

Why pagination?

If the front-end needs to display data, due to the large amount of data and one-time display, a large amount of data will appear on the page, and the loading may not be completed, which is very inefficient. At this time, paged query This problem can be solved very well by displaying huge data according to a certain number, and you can also display other data by clicking on the next page or previous page, which is more efficient!

Let’s introduce several paging queries commonly used by mybatis!
First, take a look at all the data in the database. There are comments in the detailed code

##1. Use Limit paging

sql使用的核心语句

-- 语法：表示从startIndex下标开始，一页显示pageSize个 select * from users limit startIndex,pageSize; -- 语法：表示显示[0,n]范围的数据 select * from users limit n;

Use Mybatis to implement paging and implement it based on sql

Writing interface

//分页查询 List getUserLImit(Map map);

Writing Mapper.xml

  select * from firend_mq.users limit #{startIndex},#{pageSize} 

Test class

//测试分页查询 @Test public void getUserLImit(){ SqlSession sqlSession = Mybatisutil.getSqlSession(); UserDao mapper = sqlSession.getMapper(UserDao.class); Map map = new HashMap(); map.put("startIndex",0); map.put("pageSize",3); List userLImit = mapper.getUserLImit(map); for (User user : userLImit) { System.out.println(user); } sqlSession.close(); }

Query Result:

2. RowBounds paging implementation

Based on RowBounds class object implementation, based on java code

Writing interface

//RowBounds实现分页查询 List getUserLRowBounds();

Writing Mapper.xml, the query is actually all users

  select * from firend_mq.users 

Test class

//RowBounds分页查询 @Test public void getUserLRowBounds(){ SqlSession sqlSession = Mybatisutil.getSqlSession(); //RowBounds对象 参数（起点，个数） RowBounds rowBounds = new RowBounds(2, 3); //通过java代码层面实现分页,第一个参数是接口类的方法路径 List userlist = sqlSession.selectList("dao.UserDao.getUserLRowBounds", null, rowBounds); for (User user : userlist) { System.out.println(user); } sqlSession.close(); }

Result:

3. Use the paging plug-in to achieve

#If you are interested, you can find out and post the official website link of the plug-in. There are official usage documents, learn about it by yourself

PageHelper paging plug-in