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今天就跟大家聊聊有關(guān)如何在SpringBoot2怎么中實(shí)現(xiàn)一個(gè)JPA分頁(yè)和排序分頁(yè)功能,可能很多人都不太了解,為了讓大家更加了解,小編給大家總結(jié)了以下內(nèi)容,希望大家根據(jù)這篇文章可以有所收獲。
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: # 更新或者創(chuàng)建數(shù)據(jù)表結(jié)構(gòu) ddl-auto: update # 控制臺(tái)顯示SQL show-sql: true properties: hibernate.format_sql: true
@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 }
import com.springboot.jpa.entity.Employee; import org.springframework.data.jpa.repository.JpaRepository; public interface EmployeeRepository extends JpaRepository<Employee, Integer> { }
import com.springboot.jpa.entity.Employee; import org.springframework.data.domain.Page; public interface EmployeeService { // 普通分頁(yè) Page<Employee> getPage(Integer pageNum, Integer pageLimit); // 排序分頁(yè) Page<Employee> getPageSort(Integer pageNum, Integer pageLimit); }
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; // 普通分頁(yè) @Override @Transactional(readOnly = true) // 只讀事務(wù) public Page<Employee> getPage(Integer pageNum, Integer pageLimit) { Pageable pageable =new PageRequest(pageNum - 1,pageLimit); return employeeRepository.findAll(pageable); } // 分頁(yè)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); } }
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; // 分頁(yè)顯示數(shù)據(jù) @GetMapping("/emp") public Page<Employee> showPage(@RequestParam(value = "page") Integer page, @RequestParam(value = "size") Integer size){ System.out.println("分頁(yè): page:"+page+"; size:"+size); return employeeService.getPage(page, size); } // 排序分頁(yè)顯示數(shù)據(jù) @GetMapping("/emp_sort") public Page<Employee> showSortPage(@RequestParam(value = "page") Integer page, @RequestParam(value = "size") Integer size){ System.out.println("排序分頁(yè): page:"+page+"; size:"+size); return employeeService.getPageSort(page, size); } }
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 }
補(bǔ)充:Spring Data Jpa普通分頁(yè)+排序分頁(yè)
SpringBoot2 使用jpa分頁(yè)問題
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簡(jiǎn)單分頁(yè) Page<User> getPage(Integer pageNum,Integer pageSize);
UserService
@Override public Page<User> getPage(Integer pageNum, Integer pageSize) { /** *之前看到別的博主直接new PageRequest(pageNum-1,pageSize) *自己實(shí)踐后報(bào)錯(cuò),可能是因?yàn)榘姹静灰恢掳?nbsp; *查看PageRequest的底層構(gòu)造方法并沒有對(duì)應(yīng)的只有of方法對(duì)應(yīng) *后經(jīng)實(shí)驗(yàn)成功! */ //創(chuàng)建一個(gè)pageable,調(diào)用它的實(shí)現(xiàn)類PageRequest的of()方法 Pageable pageable = PageRequest.of(pageNum - 1, pageSize); Page<User> userPage = userDao.findAll(pageable); return userPage; }
Test
@Test void testGetPage(){ //調(diào)用service層的getPage()方法 Page<User> userPage = userService.getPage(1, 5); /** * userPage.getContent() * getContent(); 獲取查詢的結(jié)果集 * Page<Object>常用方法 * List<T> getContent(); 將所有數(shù)據(jù)返回為L(zhǎng)ist * long getTotalElements();返回元素總數(shù) * int getTotalPages(); 返回分頁(yè)總數(shù) */ List<User> users = userPage.getContent(); for (User user : users) { System.out.println(user); } }
結(jié)果:
User{id=17, userName=‘大錘', 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=‘小紅', password=‘4***2', age=19} User{id=21, userName=‘小芳', password=‘2***3', age=17}
IUserService
同上
UserService
@Override public Page<User> getPage(Integer pageNum, Integer pageSize) { //普通查詢跟排序查詢的唯一區(qū)別在于Sort //排序方式,這里的by()方法跟上面的那個(gè)of()方法作用差不多 //Sort.Direction.DESC: 倒序 //Sort.Direction.ASC :默認(rèn)升序 //Sort.by(Sort.Direction.***, "實(shí)體類中的字段"); //根據(jù)實(shí)體類中的字段進(jìn)行排序(我使用的"age") Sort sort = Sort.by(Sort.Direction.DESC, "age"); //創(chuàng)建一個(gè)pageable,調(diào)用它的實(shí)現(xiàn)類PageRequest的of()方法 //將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
省略單元測(cè)試
結(jié)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=‘大錘', 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}
看完上述內(nèi)容,你們對(duì)如何在SpringBoot2怎么中實(shí)現(xiàn)一個(gè)JPA分頁(yè)和排序分頁(yè)功能有進(jìn)一步的了解嗎?如果還想了解更多知識(shí)或者相關(guān)內(nèi)容,請(qǐng)關(guān)注億速云行業(yè)資訊頻道,感謝大家的支持。
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