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;@Servicepublic 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;@RestControllerpublic 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。如有错误或未考虑完全的地方，望不吝赐教。