第九篇：Spring Boot整合Spring Data JPA_入门试炼04

六、PagingAndSortingRepository接口

前言：该接口提供了分页与排序的操作，该接口继承了CrudRepository

1、持久层接口：

public interface UserRepositoryPagingAndSorting extends PagingAndSortingRepository<Users,Integer> {
}

测试代码

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserRepositoryPagingAndSortingTest {

    @Autowired
    private UserRepositoryPagingAndSorting userRepositoryPagingAndSorting;

    /**
     * RepositoryPagingAndSorting 接口排序
     */
    @Test
    public void pagingAndSorting() {
        //order 定义排序规则
        Sort.Order order = new Sort.Order(Sort.Direction.DESC, "id");
        //sort对象封装了排序规则
        Sort sort = new Sort(order);
        List<Users> list = (List<Users>) userRepositoryPagingAndSorting.findAll(sort);
//        Iterable<Users> list = userRepositoryPagingAndSorting.findAll(sort);
        for (Users users : list) {
            System.out.println(users);
        }
    }

    /**
     * RepositoryPagingAndSorting 接口 分页
     */
    @Test
    public void pagingAndSorting2() {
//      Pageable:封装了分页的参数，当前页，每页显示的条数，他的当前页是从0开始的
//      PageRequest(page,size): page 当前页  size 每页显示的条数
        //第一页 显示数量2 如果不够2条就显示应有条数
//      Pageable pageable = new PageRequest(0, 2);
        Pageable pageable = new PageRequest(1, 2);
//        返回值Page对象
        Page<Users> page = userRepositoryPagingAndSorting.findAll(pageable);
        System.out.println("总条数:" + page.getTotalElements());
        System.out.println("总页数:" + page.getTotalPages());
        List<Users> list = page.getContent();
        for (Users users : list) {
            System.out.println(users);
        }
    }

    /**
     * RepositoryPagingAndSorting 接口 排序+分页
     */
    @Test
    public void pagingAndSorting3() {
        Sort sort = new Sort(Sort.Direction.DESC, "id");
        Pageable pageable = new PageRequest(0, 2, sort);
        Page<Users> page = userRepositoryPagingAndSorting.findAll(pageable);
        System.out.println("总条数:" + page.getTotalElements());
        System.out.println("总页数:" + page.getTotalPages());
        List<Users> list = page.getContent();
        for (Users users : list) {
            System.out.println(users);
        }
    }
}

本文源码下载：

github地址：
​​​https://github.com/gb-heima/Spring-Boot-Actual-Combat/tree/master/parent/spring-boot-chapter-9​​