法一（本地sql查询,注意表名啥的都用数据库中的名称，适用于特定数据库的查询）
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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);}[url=][/url]
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法二（jpa已经实现的分页接口，适用于简单的分页查询）
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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 beanPage<User> users = repository.findAll(new PageRequest(1, 20));[url=][/url]
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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);[url=][/url]
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//service Sort sort = new Sort(Sort.Direction.DESC,"createTime"); //创建时间降序排序 Pageable pageable = new PageRequest(pageNumber,pageSize,sort); this.depositRecordRepository.findAllByUserIdIn(userIds,pageable);//repositoryPage<DepositRecord> findAllByUserIdIn(List<Long> userIds,Pageable pageable);[url=][/url]
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法三（Query注解,hql语局，适用于查询指定条件的数据）
@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();
可以自定义整个实体(Page<User>)，也可以查询某几个字段（Page<Object[]>），和原生sql几乎一样灵活。
法四（扩充findAll，适用于动态sql查询）
public interface UserRepository extends JpaRepository<User, Long> { Page<User> findAll(Specification<User> spec, Pageable pageable);}
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@Servicepublic class UserService { @Autowired private UserRepository userRepository; public Page<User> getUsersPage(PageParam pageParam, String nickName) { //规格定义 Specification<User> specification = new Specification<User>() { /** * 构造断言 * @param root 实体对象引用 * @param query 规则查询对象 * @param cb 规则构建对象 * @return 断言 */ @Override public Predicate toPredicate(Root<User> root, CriteriaQuery<?> query, CriteriaBuilder cb) { List<Predicate> predicates = new ArrayList<>(); //所有的断言 if(StringUtils.isNotBlank(nickName)){ //添加断言 Predicate likeNickName = cb.like(root.get("nickName").as(String.class),nickName+"%"); predicates.add(likeNickName); } return cb.and(predicates.toArray(new Predicate[0])); } }; //分页信息 Pageable pageable = new PageRequest(pageParam.getPage()-1,pageParam.getLimit()); //页码：前端从1开始，jpa从0开始，做个转换 //查询 return this.userRepository.findAll(specification,pageable); }}[url=][/url]
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法五（使用entityManager，适用于动态sql查询）
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public class IncomeService{ /** * 实体管理对象 */ @PersistenceContext EntityManager entityManager; public Page<IncomeDaily> findIncomeDailysByPage(PageParam pageParam, String cpId, String appId, Date start, Date end, String sp) { StringBuilder countSelectSql = new StringBuilder(); countSelectSql.append("select count(*) from IncomeDaily po where 1=1 "); StringBuilder selectSql = new StringBuilder(); selectSql.append("from IncomeDaily po where 1=1 "); Map<String,Object> params = new HashMap<>(); StringBuilder whereSql = new StringBuilder(); if(StringUtils.isNotBlank(cpId)){ whereSql.append(" and cpId=:cpId "); params.put("cpId",cpId); } if(StringUtils.isNotBlank(appId)){ whereSql.append(" and appId=:appId "); params.put("appId",appId); } if(StringUtils.isNotBlank(sp)){ whereSql.append(" and sp=:sp "); params.put("sp",sp); } if (start == null) { start = DateUtil.getStartOfDate(new Date()); } whereSql.append(" and po.bizDate >= :startTime"); params.put("startTime", start); if (end != null) { whereSql.append(" and po.bizDate <= :endTime"); params.put("endTime", end); } String countSql = new StringBuilder().append(countSelectSql).append(whereSql).toString(); Query countQuery = this.entityManager.createQuery(countSql,Long.class); this.setParameters(countQuery,params); Long count = (Long) countQuery.getSingleResult(); String querySql = new StringBuilder().append(selectSql).append(whereSql).toString(); Query query = this.entityManager.createQuery(querySql,IncomeDaily.class); this.setParameters(query,params); if(pageParam != null){ //分页 query.setFirstResult(pageParam.getStart()); query.setMaxResults(pageParam.getLength()); } List<IncomeDaily> incomeDailyList = query.getResultList(); if(pageParam != null) { //分页 Pageable pageable = new PageRequest(pageParam.getPage(), pageParam.getLength()); Page<IncomeDaily> incomeDailyPage = new PageImpl<IncomeDaily>(incomeDailyList, pageable, count); return incomeDailyPage; }else{ //不分页 return new PageImpl<IncomeDaily>(incomeDailyList); } } /** * 给hql参数设置值 * @param query 查询 * @param params 参数 */ private void setParameters(Query query,Map<String,Object> params){ for(Map.Entry<String,Object> entry:params.entrySet()){ query.setParameter(entry.getKey(),entry.getValue()); } }
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