标签：hotel. 定义 dom hup dna exe address interface auto
实体类
@Entity @Table(name = "t_hotel") @Data public class THotel { @Id private int id; private String name; private String address; /** * 城市id */ private String city; } @Entity @Table(name = "t_city") @Data public class TCity { @Id private int id; private String name; private String state; private String country; private String map; }
新建接口
public interface TCityRepository extends JpaRepository<TCity, Integer>, JpaSpecificationExecutor<TCity> { }
单元测试类
@RunWith(SpringRunner.class) @SpringBootTest public class TCityRepositoryTest{ @Autowired private TCityRepository tCityRepository; }
shanghai的记录./** * 查找出Id小于3,并且名称带有`shanghai`的记录. * * @param id id * @param name 城市名称 * @return 城市列表 */ List<TCity> findByIdLessThanAndNameLike(int id, String name);
单元测试
@Test public void findByIdLessThanAndNameLike() throws Exception { List<TCity> shanghai = tCityRepository.findByIdLessThanAndNameLike(3, "%shanghai%"); Assert.assertTrue(shanghai.size() > 0); }
/** * 通过旅店名称分页查询旅店以及城市的信息 * * @param name 旅店名称 * @param pageable 分页信息 * @return Page<Object[]> */ @Query(value = "select t1.name as cityName,t2.name as hotelName\n" + "from t_city t1\n" + " left join t_hotel t2 on t2.city = t1.id\n" + "where t2.name = :name", countQuery = "select count(*)" + "from t_city t1 \n" + " left join t_hotel t2 on t2.city = t1.id\n" + "where t2.name = :name" , nativeQuery = true) Page<Object[]> findCityAndHotel(@Param("name") String name, Pageable pageable);
为了节约时间 我只在select 与 from 之间 分别查询了城市的名称以及旅店的名称如果要查所有的信息,可以换成
t1.* ,
t2.*
单元测试
@Test public void findCityAndHotel() throws Exception { Page<Object[]> cityAndHotel = tCityRepository.findCityAndHotel("酒店", new PageRequest(0, 10)); Assert.assertTrue(cityAndHotel.getTotalElements() > 0); }
3和2其实是一样的,为了方便我就不作出分页查询了
HQL可以用map来接受返回的参数,具体的用法如下所示:
/** * HQL通过旅店名称查询旅店以及城市的所有信息 * * @return */ @Query(value = "select new map(t1,t2) from TCity t1 left join THotel t2 on t1.id=t2.city where t2.name =:name") List<Map<String, Object>> findCityAndHotelByHQL(@Param("name") String name);
测试方法和2是差不多的 我就不粘贴了
Map
/** * 关联查询 * * @return */ @Query(value = "select new pers.zpw.domain.CityHohel(t1.name AS cityName,t2.name AS hotelName) from TCity t1 left join THotel t2 on t1.id=t2.city where t2.name =:name") List<CityHohel> findCityAndHotelByHQLResultObj(@Param("name") String name);
为了方便CityHohel我只封装了2个属性,这和HQL查询的字段是完全一致的,也必须要保持一致.
/** * Created by ZhuPengWei on 2018/5/12. */ @Data public class CityHohel { private String cityName; private String hotelName; public CityHohel(String cityName, String hotelName) { this.cityName = cityName; this.hotelName = hotelName; } }
当然这个带参的构造方法是必须要写的,否则会抛出转换实体的异常
单元测试
@Test public void findCityAndHotelByHQLResultObj() throws Exception { List<CityHohel> cityAndHotelByHQLResultObj = tCityRepository.findCityAndHotelByHQLResultObj("酒店"); Assert.assertTrue(cityAndHotelByHQLResultObj.size() > 0); }
/** * 关联查询 * * @return */ @Query(value = "select new pers.zpw.domain.CityHohel(t1.name AS cityName,t2.name AS hotelName) from TCity t1 left join THotel t2 on t1.id=t2.city where t2.name =:name", countQuery = "select count(*) from TCity t1 left join THotel t2 on t1.id=t2.city where t2.name =:name") Page<CityHohel> findCityAndHotelAllSelf(@Param("name") String name, Pageable pageable); @Test public void findCityAndHotelAllSelf() throws Exception { Page<CityHohel> cityAndHotelAllSelf = tCityRepository.findCityAndHotelAllSelf("酒店", new PageRequest(0, 10)); Assert.assertTrue(cityAndHotelAllSelf.getTotalElements() > 0); }
如果是动态查询的话当然首先得构造一条sql去查询了,当然如果不是自定义实体对象的话这样的网上一大堆我就不写了.
直接走测试
@Autowired @PersistenceContext private EntityManager entityManager; @Test public void testDynamic() throws Exception { String sql = "select new pers.zpw.domain.CityHohel(t1.name AS cityName,t2.name AS hotelName) from TCity t1 left join THotel t2 on t1.id=t2.city where t2.name =‘酒店‘"; Query query = entityManager.createQuery(sql); List resultList = query.getResultList(); Assert.assertTrue(resultList.size() > 0); }
这样测试是通过的,因此可以知道在业务层的方法中我们可以动态的构造SQL语句. 比如说可以在接口中这样子来定义一个方法
/** * 自定义查询 * @param sql * @param entityManager * @return */ default List customQuery(String sql, EntityManager entityManager) { return entityManager.createQuery(sql).getResultList(); }
然后在测试类中动态的根据条件去拼接SQL语句去调用
转载:https://blog.csdn.net/qq_36144258/article/details/80298354
Spring Data Jpa 复杂查询总结 (多表关联 以及 自定义分页 )
标签：hotel. 定义 dom hup dna exe address interface auto
原文地址：https://www.cnblogs.com/icebutterfly/p/9506021.html
