使用spring Jpa Specifications进行多条件查询

@Entity
@Table(name = "banner")
@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class Banner {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;
    private Integer moduleId;
    private Integer bannerPos;
    private String bannerName;
    private DeviceTypes deviceTypes;
    private String imageNormal;
    private String imageHd;
    private String action;
    private Integer priority = -1;
    private Long beginTime;
    private Long endTime;
    private String extra;
    private Integer status = -1;
    private Integer userScope = -1;
    private String whiteList;
    private Long createTime;
    private Long modifyTime;
    private String operator;
}

// 该接口继承自JpaRepository和JpaSpecificationExecutor类
public interface BannerRepository extends JpaRepository<Banner, Integer>, JpaSpecificationExecutor {

    /**
     * 根据banner失效时间和status查询记录，并按banner id 升序排列
     * @param ts
     * @param status
     * @return
     */
    @Query("SELECT b FROM Banner b WHERE b.endTime >= ?1 AND b.status = ?2 ORDER BY b.id ASC")
    List<Banner> getByTimeAndStatus(Long ts, Integer status);

    /**
     * 根据banner id 查询记录
     * @param id
     * @return
     */
    List<Banner> findById(Integer id);

    /**
     * 根据banner id 更新指定记录的status
     * @param id
     * @param status
     * @return
     */
    @Modifying
    @Transactional
    @Query("UPDATE Banner b set b.status = ?2 WHERE b.id = ?1")
    int updateStatus(Integer id, Integer status);

    /**
     * 查找某些特定id的banner记录
     * @param ids
     * @return
     */
    List<Banner> findByIdIn(Collection<Integer> ids);
}

// GetBannerInfoListRequest为查询请求，包含可用于查询的字段
public class BannerSpecs {
    public static Specification<Banner> where(GetBannerInfoListRequest getBannerInfoListRequest) {
        return new Specification<Banner>() {
            @Override
            public Predicate toPredicate(Root<Banner> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
                List<Predicate> predicates = new ArrayList<Predicate>();
                // 若查询条件字段为空，直接返回
                if (getBannerInfoListRequest == null) {
                    return null;
                }
                // 根据status进行equal等值查询
                if (getBannerInfoListRequest.getStatus() != null) {
                    predicates.add(criteriaBuilder.equal(root.get("status"), getBannerInfoListRequest.getStatus()));
                }
                // 根据moduleId进行equal等值查询
                if (getBannerInfoListRequest.getModuleId() != null) {
                    predicates.add(criteriaBuilder.equal(root.get("moduleId"), getBannerInfoListRequest.getModuleId()));
                }
                // 根据bannerPos进行equal等值查询
                if (getBannerInfoListRequest.getBannerPos() != null) {
                    predicates.add(criteriaBuilder.equal(root.get("bannerPos"), getBannerInfoListRequest.getBannerPos()));
                }
                // 根据bannerName进行模糊匹配查询
                if (getBannerInfoListRequest.getBannerName() != null) {
                    predicates.add(criteriaBuilder.like(root.get("bannerName"), "%" + getBannerInfoListRequest.getBannerName() + "%"));
                }
                // 查询beginTime在某段时间范围内的记录
                if (getBannerInfoListRequest.getBeginTime() != null) {
                    predicates.add(criteriaBuilder.gt(root.get("beginTime"), getBannerInfoListRequest.getBeginTime()));
                }
                if (getBannerInfoListRequest.getEndTime() != null) {
                    predicates.add(criteriaBuilder.lt(root.get("beginTime"), getBannerInfoListRequest.getEndTime()));
                }
                return criteriaQuery.where(predicates.toArray(new Predicate[0])).getRestriction();
            }
        };
    }
}

public interface JpaSpecificationExecutor<T> {
    // 获取满足条件的一个元素
	T findOne(Specification<T> spec);
    // 获取满足条件的所有元素
	List<T> findAll(Specification<T> spec);
    // 通过分页的形式返回满足条件的所有元素
	Page<T> findAll(Specification<T> spec, Pageable pageable);
    // 通过排序的形式返回满足条件的所有元素
	List<T> findAll(Specification<T> spec, Sort sort);
    // 返回满足条件的元素的个数
	long count(Specification<T> spec);
}

@Autowired
private BannerRepository bannerRepository;

// 查询条件
GetBannerInfoListRequest request = new GetBannerInfoListRequest(1,2,3,"test",1234,5678);
Specification<Banner> bannerFilter = BannerSpecs.where(request); 
// 查询中status=1,moduleId=2,bannerPos=3,bannerName中含有test、起始时间在1234~5678之间 的所有元素
List<Banner> banners = bannerRepository.findAll(bannerFilter);