spring data jpa 分页查询

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）

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);

}

 

法二（jpa已经实现的分页接口，适用于简单的分页查询）

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"); //创建时间降序排序
 Pageable pageable = new PageRequest(pageNumber,pageSize,sort);
 this.depositRecordRepository.findAllByUserIdIn(userIds,pageable);
//repository

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

 

 

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);

} 

@Service
public 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);

}
}

 

法五（使用entityManager，适用于动态sql查询）

@Service
@Transactional
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());

}

}
}