spring data jpa 分頁查詢(小結)

原文:https://www.cnblogs.com/hdwang/p/7843405.html

spring data jpa 分頁查詢

方法一（本地sql查詢,注意表名啥的都用數據庫中的名稱，適用於特定數據庫的查詢）

public interface UserRepository extends JpaRepository<User, Long> {

  @Query(value = "SELECT * FROM USERS WHERE LASTNAME = ?1",
    countQuery = "SELECT count(*) FROM USERS WHERE LASTNAME = ?1",
    nativeQuery = true)
  Page<User> findByLastname(String lastname, Pageable pageable);
}

方法二（jpa已經實現的分頁接口，適用於簡單的分頁查詢）

public interface PagingAndSortingRepository<T, ID extends Serializable>
  extends CrudRepository<T, ID> {

  Iterable<T> findAll(Sort sort);

  Page<T> findAll(Pageable pageable);
}

Accessing the second page of User by a page size of 20 you could simply do something like this:

PagingAndSortingRepository<User, Long> repository = // … get access to a bean
Page<User> users = repository.findAll(new PageRequest(1, 20));

User findFirstByOrderByLastnameAsc();

User findTopByOrderByAgeDesc();

Page<User> queryFirst10ByLastname(String lastname, Pageable pageable);

Slice<User> findTop3ByLastname(String lastname, Pageable pageable);

List<User> findFirst10ByLastname(String lastname, Sort sort);

List<User> findTop10ByLastname(String lastname, Pageable pageable);

 

//service
 Sort sort = new Sort(Sort.Direction.DESC,"createTime"); //創建時間降序排序
 Pageable pageable = new PageRequest(pageNumber,pageSize,sort);
 this.depositRecordRepository.findAllByUserIdIn(userIds,pageable);

//repository
Page<DepositRecord> findAllByUserIdIn(List<Long> userIds,Pageable pageable);

 

 

方法三（Query注解,hql語局，適用於查詢指定條件的數據）

 @Query(value = "select b.roomUid from RoomBoard b where b.userId=:userId and b.lastBoard=true order by  b.createTime desc")
    Page<String> findRoomUidsByUserIdPageable(@Param("userId") long userId, Pageable pageable);

Pageable pageable = new PageRequest(pageNumber,pageSize);
Page<String> page = this.roomBoardRepository.findRoomUidsByUserIdPageable(userId,pageable);
List<String> roomUids = page.getContent();

 

可以自定義整個實體(Page<User>)，也可以查詢某幾個字段（Page<Object[]>），和原生sql幾乎一樣靈活。

方法四（擴充findAll，適用於動態sql查詢）

public interface UserRepository extends JpaRepository<User, Long> {

    Page<User> findAll(Specification<User> spec, Pageable pageable);
} 

@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

    public Page<User> getUsersPage(PageParam pageParam, String nickName) {
        //規格定義
        Specification<User> specification = new Specification<User>() {

            /**
             * 構造斷言
             * @param root 實體對象引用
             * @param query 規則查詢對象
             * @param cb 規則構建對象
             * @return 斷言
             */
            @Override
            public Predicate toPredicate(Root<User> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
                List<Predicate> predicates = new ArrayList<>(); //所有的斷言
                if(StringUtils.isNotBlank(nickName)){ //添加斷言
                    Predicate likeNickName = cb.like(root.get("nickName").as(String.class),nickName+"%");
                    predicates.add(likeNickName);
                }
                return cb.and(predicates.toArray(new Predicate[0]));
            }
        };
        //分頁信息
        Pageable pageable = new PageRequest(pageParam.getPage()-1,pageParam.getLimit()); //頁碼：前端從1開始，jpa從0開始，做個轉換
        //查詢
        return this.userRepository.findAll(specification,pageable);
    }

}