MyBatis ----- 7.pageHelper Paging Assistant

pageHelper is a free plug-in paging, it can be applied to a variety of databases.

Use tab plug can greatly reduce the amount of code, the method used here will be described the plug tab.

1. Download

https://github.com/pagehelper/Mybatis-PageHelper

I'm using here is jsqlparser-2.0.jar + pagehelper-5.1.10.jar

2. How to use:

2.1 Configuring Paging Assistant:

　　Conf.xml add the following code, note added <properties resource = "db.properties" /> later

<! - Configuration tab widget -> 
< plugins > 
        <! - com.github.pagehelper package name for the class is PageHelper -> 
            < plugin Interceptor = "com.github.pagehelper.PageInterceptor" > 
                 <! - Set database type Oracle, Mysql, MariaDB, SQLite, Hsqldb, PostgreSQL database six kinds -> 
             < Property name = "helperDialect" value = "MySQL" /> 
        </ plugin > 
</ plugins >

2.2 is defined UsersMapper.xml

<?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">
<!--  com.zhiyou.zyl.UsersMapper.getUser -->
<mapper namespace="com.zhiyou.zyl.dao.UsersDao">
    <select id="selectAll" resultType="com.zhiyou.zyl.bean.Users">
        select * from users
    </select>
</mapper>

2.3 Test Page

  class UsersTest {
     static the SqlSession the session = null ;
     static UsersDao UD; 
    @BeforeAll 
    static  void setUpBeforeClass () throws Exception { 
        String Resource = "conf.xml" ;
         // load mybatis profile (which also load the associated map file) 
        Reader Reader = Resources.getResourceAsReader (Resource);
         // build sqlSession factory 
        SqlSessionFactory sessionFactory = new new the SqlSessionFactoryBuilder () build (Reader);.
         // create a map file can be executed in the sql sqlSession 
        the session = sessionFactory.openSession();
        
        ud=session.getMapper(UsersDao.class);
    }

    @AfterAll
    static void tearDownAfterClass() throws Exception {
        //提交
        session.commit();
    }

    @Test
    void testSelectAll() {
        int pageNum=1;
        int pageSize=2;
        PageHelper.startPage(pageNum, pageSize);
    
        List<Users> users=ud.selectAll();
        PageInfo<Users> list = new PageInfo<Users>(users);        
        
        System.out.println(list);
    }

2.4 operating results

PageInfo{pageNum=1, pageSize=2, size=2, startRow=1, endRow=2, total=4, pages=2, list=Page{count=true, pageNum=1, pageSize=2, startRow=0, endRow=2, total=4, pages=2, reasonable=false, pageSizeZero=false}[Users [id=1, name=张三, age=18], Users [id=2, name=李四, age=19]], prePage=0, nextPage=2, isFirstPage=true, isLastPage=false, hasPreviousPage=false, hasNextPage=true, navigatePages=8, navigateFirstPage=1, navigateLastPage=2, navigatepageNums=[1, 2]}

2.5pageInfo property description:

pageNum: current page number

pageSize: pieces of data per page

size: The current number of page data

startRow / endRow: start / end number of

total: total number of

pages: Pages

list: the result set

prePage / nextPage: Prev / Next

isFirstPage / isLastPage: whether the first / last page

hasPreviousPage / hasNextPage: Is there Previous / Next

navigatePages: navigation Page Number

navigateFirstPage: the first page navigation

navigateLastPage: navigation Next

navigatePageNums: all navigation pages