SpringBoot JPA Pagination

JPA를 쓰는건 참 편리하고 좋은데, 페이징도 자동으로 해주면 참 좋겠죠? 간단하게 페이징을 할 수 있는 방법을 알아봅니다.

1. JPA Pagination

이번 포스팅은 아래의 포스트들을 기반으로 작성되었습니다.

o    Spring Boot with STS(Spring Tool Suite)

o    SpringBoot JPA 예제

미리 읽고 오시면 더욱 좋습니다. :D

2. Create Project

페이징 데모를 위해서 프로젝트를 생성합니다.

Name : pagination

Type : Gradle Project

Packaging : Jar

Java Version : 1.7

Language : Java

Boot Version : 1.2.4

Group : kr.jdm

Artifact : pagination

Version : 0.0.1-SNAPSHOT

Description : Demo project for Spring Boot

Package : jpa

Dependencies : H2, JPA

3. Example

이제 실제로 코드를 짜봅니다. 시나리오는 정해진 아이템 개수만큼 N번째 페이지에 있는 게시물 목록을 호출하는겁니다.

3.1. Entity

간단한 게시물 Entity입니다.

package pagination;

 

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

 

@Entity

public class BoardEntity {

 

               @Id

               @GeneratedValue(strategy=GenerationType.AUTO)

               private int seq; // 게시글 번호

 

               @Column

               private String author; // 게시글 작성자

 

               @Column

               private String subject; // 게시글 제목

 

               @Column

               private String content; // 게시글 본문

 

               public BoardEntity() {}

 

               public int getSeq() {

                               return seq;

               }

 

               public void setSeq(int seq) {

                               this.seq = seq;

               }

 

               public String getAuthor() {

                               return author;

               }

 

               public void setAuthor(String author) {

                               this.author = author;

               }

 

               public String getSubject() {

                               return subject;

               }

 

               public void setSubject(String subject) {

                               this.subject = subject;

               }

 

               public String getContent() {

                               return content;

               }

 

               public void setContent(String content) {

                               this.content = content;

               }

}

3.2. Repository

게시물 Repostiory입니다. @Query 메소드도 있고 Name 기반 메소드도 있습니다.

package pagination;

 

import org.springframework.data.domain.Page;

import org.springframework.data.domain.Pageable;

import org.springframework.data.jpa.repository.Query;

import org.springframework.data.repository.PagingAndSortingRepository;

import org.springframework.data.repository.query.Param;

 

public interface BoardRepository extends PagingAndSortingRepository<BoardEntity, Integer> {

               Page<BoardEntity> findAll(Pageable pageable);

               Page<BoardEntity> findAllByOrderBySeqDesc(Pageable pageable);

               Page<BoardEntity> findAllByAuthor(String author, Pageable pageable);

 

               @Query("select t  from BoardEntity t where content like concat('%', :searchString ,'%')")

               Page<BoardEntity> findAllSearch(@Param("searchString") String searchString, Pageable pageable);

 

}

3.3. Application

실제로 구동 시키기 위한 코드입니다. 테스트 코드가 아닙니다. 테스트 코드는 Junit으로 작성합시다. :)

package pagination;

 

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.CommandLineRunner;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.data.domain.Page;

import org.springframework.data.domain.PageRequest;

import org.springframework.data.domain.Sort;

import org.springframework.data.domain.Sort.Direction;

 

@SpringBootApplication

public class PaginationApplication implements CommandLineRunner {

 

               @Autowired

               private BoardRepository boardRepository;

 

   public static void main(String[] args) {

       SpringApplication.run(PaginationApplication.class, args);

   }

 

               @Override

               public void run(String... arg0) throws Exception {

 

                               // 미리 아이템 100개를 적재

                               for(int i = 0 ; i < 100; i++){

                                              BoardEntity be = new BoardEntity();

                                              be.setContent(dummyString());

                                              if( i % 3 == 0 ){

                                                              be.setAuthor("first");

                                              }

                                              else if( i % 3 == 1 ) {

                                                             be.setAuthor("second");

                                              }

                                              else {

                                                             be.setAuthor("third");

                                              }

                                              boardRepository.save(be);

                               }

 

                               // 한 페이지 아이템 10개, 0번째 페이지 호출

                               Page<BoardEntity> page = boardRepository.findAll(new PageRequest(0, 10));

                               printPageData("simple", page);

 

                               // 한 페이지 아이템 10개, 글번호 내림차순으로, 0번째 페이지 호출

                               page = boardRepository.findAllByOrderBySeqDesc(new PageRequest(0, 10));

                               printPageData("sort_seq_desc", page);

 

                               // 한 페이지에 아이템 10개, 글번호 내림차순으로, 2번째 페이지 호출

                               page = boardRepository.findAll(new PageRequest(2, 10, new Sort(Direction.DESC, "seq")));

                               printPageData("sort", page);

 

                               // 한페이지에 아이템 10개, 글작성자 "first", 0번째 페이지 호출

                               page = boardRepository.findAllByAuthor("first", new PageRequest(0, 10));

                               printPageData("sort_author", page);

 

                               // 한페이지 아이템 10개, 작성자 내림차순으로, 2번째 페이지 호출

                               page = boardRepository.findAll(new PageRequest(2, 10, new Sort(Direction.DESC, "author")));

                               printPageData("sort_author_desc", page);

 

                               // 한페이지 아이템 10개, 검색어 중, 글번호 내림차순으로, 2번째 페이지 호출

                               page = boardRepository.findAllSearch("bc", new PageRequest(2, 10, new Sort(Direction.DESC, "seq")));

                               printPageData("sort_search_desc", page);

 

               }

 

               // 페이지 데이터 출력

               private void printPageData(String label, Page<BoardEntity> page){

                               if( page == null || page.getSize() <= 0 ) return;

 

                               for( int i = 0 ; i < page.getSize(); i++ ){

                                              BoardEntity be = page.getContent().get(i);

                                              System.out.println("["+label+"] "+ be.getSeq() + " " + be.getAuthor() + " " + be.getContent());

                               }

               }

 

               // 더미 문자열 반환

               private String dummyString(){

 

                               String [] dummy = {"abc", "bcd", "cde", "def"};

                               int rand = (int)(System.currentTimeMillis() % dummy.length);

 

                               return dummy[rand];

               }

}

3.4. check result

결과 화면을 봅시다.

[simple] 1 first bcd

[simple] 2 second cde

[simple] 3 third def

[simple] 4 first def

[simple] 5 second cde

[simple] 6 third def

[simple] 7 first abc

[simple] 8 second abc

[simple] 9 third bcd

[simple] 10 first cde

[sort_seq_desc] 100 first cde

[sort_seq_desc] 99 third cde

[sort_seq_desc] 98 second bcd

[sort_seq_desc] 97 first bcd

[sort_seq_desc] 96 third abc

[sort_seq_desc] 95 second abc

[sort_seq_desc] 94 first def

[sort_seq_desc] 93 third def

[sort_seq_desc] 92 second cde

[sort_seq_desc] 91 first cde

[sort] 80 second abc

[sort] 79 first abc

[sort] 78 third def

[sort] 77 second def

[sort] 76 first cde

[sort] 75 third cde

[sort] 74 second bcd

[sort] 73 first bcd

[sort] 72 third abc

[sort] 71 second abc

[sort_author] 1 first bcd

[sort_author] 4 first def

[sort_author] 7 first abc

[sort_author] 10 first cde

[sort_author] 13 first abc

[sort_author] 16 first cde

[sort_author] 19 first abc

[sort_author] 22 first cde

[sort_author] 25 first abc

[sort_author] 28 first cde

[sort_author_desc] 69 third def

[sort_author_desc] 6 third def

[sort_author_desc] 12 third def

[sort_author_desc] 9 third bcd

[sort_author_desc] 99 third cde

[sort_author_desc] 72 third abc

[sort_author_desc] 3 third def

[sort_author_desc] 75 third cde

[sort_author_desc] 96 third abc

[sort_author_desc] 15 third bcd

[sort_search_desc] 58 first bcd

[sort_search_desc] 57 third bcd

[sort_search_desc] 56 second abc

[sort_search_desc] 55 first abc

[sort_search_desc] 50 second bcd

[sort_search_desc] 49 first bcd

[sort_search_desc] 48 third abc

[sort_search_desc] 47 second abc

[sort_search_desc] 42 third bcd

[sort_search_desc] 41 second bcd