[开发测试] 【MyBatis-09】MyBatis分页插件

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-> 开发测试 -> 【MyBatis-09】MyBatis分页插件 -> 正文阅读

[开发测试]【MyBatis-09】MyBatis分页插件

文章目录

一、分页插件配置步骤

1.1 添加依赖

<dependency>
	<groupId>com.github.pagehelper</groupId>
	<artifactId>pagehelper</artifactId>
	<version>5.2.0</version>
</dependency>

1.2 配置分页插件

在MyBatis的核心配置文件（mybatis-config.xml）中配置插件

<plugins>
	<!--设置分页插件-->
	<plugin interceptor="com.github.pagehelper.PageInterceptor"></plugin>
</plugins>

二、分页插件的使用步骤

2.1 开启分页功能

在查询功能之前使用PageHelper.startPage(int pageNum, int pageSize)开启分页功能
- pageNum：当前页的页码
- pageSize：每页显示的条数

	@Test
    public void testPageHelper() throws IOException {
        InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        EmpMapper mapper = sqlSession.getMapper(EmpMapper.class);
        //访问第一页，每页四条数据
        PageHelper.startPage(1,4);
        List<Emp> emps = mapper.selectByExample(null);
        emps.forEach(System.out::println);
    }

输出：

DEBUG 04-20 19:18:15,001 Cache Hit Ratio [SQL_CACHE]: 0.0 (LoggingCache.java:60) 
DEBUG 04-20 19:18:15,117 ==>  Preparing: SELECT count(0) FROM t_emp (BaseJdbcLogger.java:137) 
DEBUG 04-20 19:18:15,186 ==> Parameters:  (BaseJdbcLogger.java:137) 
DEBUG 04-20 19:18:15,256 <==      Total: 1 (BaseJdbcLogger.java:137) 
DEBUG 04-20 19:18:15,258 ==>  Preparing: select eid, emp_name, age, sex, email, did from t_emp LIMIT ? (BaseJdbcLogger.java:137) 
DEBUG 04-20 19:18:15,259 ==> Parameters: 4(Integer) (BaseJdbcLogger.java:137) 
DEBUG 04-20 19:18:15,262 <==      Total: 4 (BaseJdbcLogger.java:137) 
Emp{eid=1, empName='admin', age=22, sex='null', email='456@qq.com', did=3}
Emp{eid=2, empName='admin2', age=22, sex='女', email='456@qq.com', did=3}
Emp{eid=3, empName='王五', age=13, sex='男', email='14@qq.com', did=3}
Emp{eid=4, empName='赵六', age=25, sex='女', email='32@qq.com', did=1}

2.2 分页相关数据

2.2.1 方法一：直接输出

	 @Test
    public void testPageHelper() throws IOException {
        InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        EmpMapper mapper = sqlSession.getMapper(EmpMapper.class);
        //访问第一页，每页四条数据
        Page<Object> page = PageHelper.startPage(1, 4);
        List<Emp> emps = mapper.selectByExample(null);
        //在查询到List集合后，打印分页数据
        System.out.println(page);
    }

输出数据：

Page{count=true, pageNum=1, pageSize=4, startRow=0, endRow=4, 
total=8, pages=2, reasonable=false, pageSizeZero=false}[
Emp{eid=1, empName='admin', age=22, sex='null', email='456@qq.com', did=3}, 
Emp{eid=2, empName='admin2', age=22, sex='女', email='456@qq.com', did=3}, 
Emp{eid=3, empName='王五', age=13, sex='男', email='14@qq.com', did=3}, 
Emp{eid=4, empName='赵六', age=25, sex='女', email='32@qq.com', did=1}]

2.2.2 方法二：使用PageInfo

	@Test
    public void testPageHelper() throws IOException {
        InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        EmpMapper mapper = sqlSession.getMapper(EmpMapper.class);
        //访问第一页，每页四条数据
        PageHelper.startPage(1, 4);
        List<Emp> emps = mapper.selectByExample(null);
        //设置导航分页页码数为5
        PageInfo<Emp> page = new PageInfo<>(emps,5);
        System.out.println(page);
    }

输出：

PageInfo{pageNum=1, pageSize=4, size=4, startRow=1, endRow=4, total=8, pages=2, 

list=Page{count=true, pageNum=1, pageSize=4, startRow=0, endRow=4, total=8, pages=2, reasonable=false, pageSizeZero=false}[
Emp{eid=1, empName='admin', age=22, sex='null', email='456@qq.com', did=3}, Emp{eid=2, empName='admin2', age=22, sex='女', email='456@qq.com', did=3}, 
Emp{eid=3, empName='王五', age=13, sex='男', email='14@qq.com', did=3}, 
Emp{eid=4, empName='赵六', age=25, sex='女', email='32@qq.com', did=1}], 

prePage=0, nextPage=2, isFirstPage=true, isLastPage=false, hasPreviousPage=false, hasNextPage=true, navigatePages=5, navigateFirstPage=1, navigateLastPage=2, navigatepageNums=[1, 2]}