SpringBoot2 实现JPA分页和排序分页的案例

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脚本之家。如有错误或未考虑完全的地方，望不吝赐教。

来源：https://blog.csdn.net/yhflyl/article/details/81432266