分页插件的使用
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);
}
分页相关数据
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);
}
- 分页相关数据：
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='男', email='456@qq.com', did=3}, Emp{eid=2, empName='admin2', age=22, sex='男', email='456@qq.com', did=3}, Emp{eid=3, empName='王五', age=12, sex='女', email='123@qq.com', did=3}, Emp{eid=4, empName='赵六', age=32, sex='男', email='123@qq.com', did=1}]
方法二使用PageInfo
-
在查询获取list集合之后，使用
PageInfo<T> pageInfo = new PageInfo<>(List<T> list, intnavigatePages)获取分页相关数据 -
list：分页之后的数据
- navigatePages：导航分页的页码数
@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);
PageHelper.startPage(1, 4);
List<Emp> emps = mapper.selectByExample(null);
PageInfo<Emp> page = new PageInfo<>(emps,5);
System.out.println(page);
}
- 分页相关数据：
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='男', email='456@qq.com', did=3}, Emp{eid=2, empName='admin2', age=22, sex='男', email='456@qq.com', did=3}, Emp{eid=3, empName='王五', age=12, sex='女', email='123@qq.com', did=3}, Emp{eid=4, empName='赵六', age=32, sex='男', email='123@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]}
- 其中list中的数据等同于方法一中直接输出的page数据
常用数据：
- pageNum：当前页的页码
- pageSize：每页显示的条数
- size：当前页显示的真实条数
- total：总记录数
- pages：总页数
- prePage：上一页的页码
- nextPage：下一页的页码
- isFirstPage/isLastPage：是否为第一页/最后一页
- hasPreviousPage/hasNextPage：是否存在上一页/下一页
- navigatePages：导航分页的页码数
- navigatepageNums：导航分页的页码，[1,2,3,4,5]
