分页 application.yml spring: datasource: url: jdbc:mysql://127.0.0.1/jpauseUnicode=truecharacterEncoding=utf-8useSSL=false username: root password: 123456 driver-class-name: com.mysql.jdbc.Driver jpa: hibernate: # 更新或者创建数据表
分页
application.yml
spring: datasource: url: jdbc:mysql://127.0.0.1/jpa?useUnicode=true&characterEncoding=utf-8&useSSL=false username: root password: 123456 driver-class-name: com.mysql.jdbc.Driver jpa: hibernate: # 更新或者创建数据表结构 ddl-auto: update # 控制台显示SQL show-sql: true properties: hibernate.format_sql: true
实体类
@Entity @Table(name = "employee") public class Employee { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer empId; private String lastName; private String email; @Temporal(TemporalType.DATE) private Date birth; @Temporal(TemporalType.TIMESTAMP) private Date createTime; @ManyToOne @JoinColumn(name = "dept_id") private Department department; // 省去 set get方法 } @Entity @Table(name = "department") public class Department { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer deptId; private String deptName; // 省去 set get方法 }
Repository接口类
import com.springboot.jpa.entity.Employee; import org.springframework.data.jpa.repository.JpaRepository; public interface EmployeeRepository extends JpaRepository<Employee, Integer> { }
service 接口类
import com.springboot.jpa.entity.Employee; import org.springframework.data.domain.Page; public interface EmployeeService { // 普通分页 Page<Employee> getPage(Integer pageNum, Integer pageLimit); // 排序分页 Page<Employee> getPageSort(Integer pageNum, Integer pageLimit); }
Service 实现类
import com.springboot.jpa.dao.EmployeeRepository; import com.springboot.jpa.entity.Employee; import com.springboot.jpa.service.EmployeeService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.data.domain.Page; import org.springframework.data.domain.PageRequest; import org.springframework.data.domain.Pageable; import org.springframework.data.domain.Sort; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; @Service public class EmployeeServiceImpl implements EmployeeService { @Autowired private EmployeeRepository employeeRepository; // 普通分页 @Override @Transactional(readOnly = true) // 只读事务 public Page<Employee> getPage(Integer pageNum, Integer pageLimit) { Pageable pageable =new PageRequest(pageNum - 1,pageLimit); return employeeRepository.findAll(pageable); } // 分页排序 @Override @Transactional(readOnly = true) public Page<Employee> getPageSort(Integer pageNum, Integer pageLimit) { Sort sort = new Sort(Sort.Direction.DESC,"createTime"); Pageable pageable =new PageRequest(pageNum - 1, pageLimit, sort); return employeeRepository.findAll(pageable); } }
Controller控制器类
import com.springboot.jpa.entity.Employee; import com.springboot.jpa.service.EmployeeService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.data.domain.Page; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; @RestController public class EmployeeController { @Autowired private EmployeeService employeeService; // 分页显示数据 @GetMapping("/emp") public Page<Employee> showPage(@RequestParam(value = "page") Integer page, @RequestParam(value = "size") Integer size){ System.out.println("分页: page:"+page+"; size:"+size); return employeeService.getPage(page, size); } // 排序分页显示数据 @GetMapping("/emp_sort") public Page<Employee> showSortPage(@RequestParam(value = "page") Integer page, @RequestParam(value = "size") Integer size){ System.out.println("排序分页: page:"+page+"; size:"+size); return employeeService.getPageSort(page, size); } }
分页显示的json格式串
http://localhost:8080/emp_sort?page=1&size=10 url格式
{ "content": [{ "lastName": "7QW", "email": "453@qq.com", "birth": "2018-08-06", "createTime": "2018-08-30T07:40:34.000+0000", "id": 5, "dempartment": { "deptName": "BBB", "id": 2 } }, { "lastName": "qax", "email": "1223@qq.com", "birth": "2018-08-06", "createTime": "2018-08-24T07:40:56.000+0000", "id": 6, "dempartment": { "deptName": "AAA", "id": 1 } } }], "pageable": { "sort": { "sorted": true, "unsorted": false }, "offset": 0, "pageNumber": 0, "pageSize": 10, "unpaged": false, "paged": true }, "last": true, "totalElements": 6, "totalPages": 1, "number": 0, "size": 10, "sort": { "sorted": true, "unsorted": false }, "numberOfElements": 6, "first": true }
补充:Spring Data Jpa普通分页+排序分页
SpringBoot2 使用jpa分页问题
一、 jap的普通分页:
pojo
@Entity @Table(name = "user") public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer id; @Column private String userName; @Column private String password; @Column private String age; //省略get、set }
IUserService
//jpa简单分页 Page<User> getPage(Integer pageNum,Integer pageSize);
UserService
@Override public Page<User> getPage(Integer pageNum, Integer pageSize) { /** *之前看到别的博主直接new PageRequest(pageNum-1,pageSize) *自己实践后报错,可能是因为版本不一致吧 *查看PageRequest的底层构造方法并没有对应的只有of方法对应 *后经实验成功! */ //创建一个pageable,调用它的实现类PageRequest的of()方法 Pageable pageable = PageRequest.of(pageNum - 1, pageSize); Page<User> userPage = userDao.findAll(pageable); return userPage; }
Test
@Test void testGetPage(){ //调用service层的getPage()方法 Page<User> userPage = userService.getPage(1, 5); /** * userPage.getContent() * getContent(); 获取查询的结果集 * Page<Object>常用方法 * List<T> getContent(); 将所有数据返回为List * long getTotalElements();返回元素总数 * int getTotalPages(); 返回分页总数 */ List<User> users = userPage.getContent(); for (User user : users) { System.out.println(user); } }
结果:
User{id=17, userName=‘大锤', password=‘1***3', age=23} User{id=18, userName=‘小黑', password=‘w***w', age=21} User{id=19, userName=‘小白', password=‘2***1', age=29} User{id=20, userName=‘小红', password=‘4***2', age=19} User{id=21, userName=‘小芳', password=‘2***3', age=17}
二、 jap的普通分页:
IUserService
同上
UserService
@Override public Page<User> getPage(Integer pageNum, Integer pageSize) { //普通查询跟排序查询的唯一区别在于Sort //排序方式,这里的by()方法跟上面的那个of()方法作用差不多 //Sort.Direction.DESC: 倒序 //Sort.Direction.ASC :默认升序 //Sort.by(Sort.Direction.***, "实体类中的字段"); //根据实体类中的字段进行排序(我使用的"age") Sort sort = Sort.by(Sort.Direction.DESC, "age"); //创建一个pageable,调用它的实现类PageRequest的of()方法 //将sort加入到of()中排序完成 Pageable pageable = PageRequest.of(pageNum - 1, pageSize,sort); Page<User> userPage = userDao.findAll(pageable); return userPage; }
Test
省略单元测试
结果:
User{id=19, name=‘小白', password=‘2***1', age=29} User{id=16, name=‘老李', password=‘8***7', age=25} User{id=17, name=‘大锤', password=‘1***3', age=23} User{id=15, name=‘老宋', password=‘9***0', age=22} User{id=18, name=‘小黑', password=‘w***w', age=21}
以上为个人经验,希望能给大家一个参考,也希望大家多多支持易盾网络。如有错误或未考虑完全的地方,望不吝赐教。