7. Spring Data JPA : 데이터 조회 Page<T>

 

 

Page<T>는 단순 데이터만의 추출하는 용도가 아니라, 웹에서 필요한 데이터들을 추가적으로 처리해 준다.

package com.kyhslam.persistence;

import java.util.Collection;
import java.util.List;

import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.repository.CrudRepository;

import com.kyhslam.domain.Board;

public interface BoardRepository extends CrudRepository<Board, Long> {


	public Page<Board> findByBnoGreaterThan(Long bno, Pageable paging);
}

 

테스트 코드

package com.kyhslam;

import java.util.Collection;
import java.util.List;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
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.test.context.junit4.SpringRunner;

import com.kyhslam.domain.Board;
import com.kyhslam.persistence.BoardRepository;

@RunWith(SpringRunner.class)
@SpringBootTest
public class boot3ApplicationTest {

	@Autowired
	private BoardRepository repo;
	
    
	@Test
	public void testBnoPagingSort() {
		Pageable paging = PageRequest.of(0, 10, Sort.Direction.ASC, "bno");
		
		Page<Board> result = repo.findByBnoGreaterThan(0L, paging);
		
		System.out.println("PAGE SIZE : " + result.getSize());
		System.out.println("TOTAL PAGES : " + result.getTotalPages());
		System.out.println("TOTAL COUNT : " + result.getTotalElements());
		System.out.println("NEXT : " + result.nextPageable());
		
		List<Board> list = result.getContent();
		
		list.forEach(board -> System.out.println(board.toString()));
		
		
		//Collection<Board> results = repo.findByBnoGreaterThan(0L, paging);
		//results.forEach(board -> System.out.println(board.toString()));
	}
	
}

 

결과

Hibernate: select * from ( select board0_.bno as bno1_0_, board0_.content as content2_0_, 
board0_.regdate as regdate3_0_, board0_.title as title4_0_, board0_.updatedate as 
updatedate5_0_, board0_.writer as writer6_0_ from tbl_boards board0_ where board0_.bno>? 
order by board0_.bno asc ) where rownum <= ?

Hibernate: select count(board0_.bno) as col_0_0_ from tbl_boards board0_ where board0_.bno>?

PAGE SIZE : 10
TOTAL PAGES : 20
TOTAL COUNT : 200
NEXT : Page request [number: 1, size 10, sort: bno: ASC]
Board [bno=1, title=제목..1, writer=user01, content=내용....1 채우기 , regdate=2020-06-09 14:29:03.466, updatedate=2020-06-09 14:29:03.466]
Board [bno=2, title=제목..2, writer=user02, content=내용....2 채우기 , regdate=2020-06-09 14:29:03.524, updatedate=2020-06-09 14:29:03.524]
Board [bno=3, title=제목..3, writer=user03, content=내용....3 채우기 , regdate=2020-06-09 14:29:03.551, updatedate=2020-06-09 14:29:03.551]
Board [bno=4, title=제목..4, writer=user04, content=내용....4 채우기 , regdate=2020-06-09 14:29:03.571, updatedate=2020-06-09 14:29:03.571]
Board [bno=5, title=제목..5, writer=user05, content=내용....5 채우기 , regdate=2020-06-09 14:29:03.59, updatedate=2020-06-09 14:29:03.59]
Board [bno=6, title=제목..6, writer=user06, content=내용....6 채우기 , regdate=2020-06-09 14:29:03.616, updatedate=2020-06-09 14:29:03.616]
Board [bno=7, title=제목..7, writer=user07, content=내용....7 채우기 , regdate=2020-06-09 14:29:03.671, updatedate=2020-06-09 14:29:03.671]
Board [bno=8, title=제목..8, writer=user08, content=내용....8 채우기 , regdate=2020-06-09 14:29:03.694, updatedate=2020-06-09 14:29:03.694]
Board [bno=9, title=제목..9, writer=user09, content=내용....9 채우기 , regdate=2020-06-09 14:29:03.712, updatedate=2020-06-09 14:29:03.712]
Board [bno=10, title=제목..10, writer=user00, content=내용....10 채우기 , regdate=2020-06-09 14:29:03.73, updatedate=2020-06-09 14:29:03.73]

 

결과를 보면 SQL문이 두 번 실행된다는 점이다.(만일 데이터 수가 적어서 지정된 사이즈 이하인 경우에는 한 번만 실행 된다.)