@Data
public class NameOnlyDto ? implements Serializable {
? ? private ?String ?firstName;
? ? private ?String ?lastName;
? ? private ?String ?sex ;
}

@Repository
public class CustomEntity {
? ? // 實體管理器EntityManager是負責管理Entity的對象。對Entity的操作包括添加、刪除、修改和查詢，都是通過實體管理器來實現(xiàn)的。
? ? @PersistenceContext
? ? private EntityManager entityManager;
?
? ? //EntityManagerFactory
?
? ? @Transactional
? ? public List<NameOnlyDto> listNameOnlyDto(){
? ? ? ? String sql = "select p.last_name lastName, p.first_name firstName from PERSON p";
? ? ? ? // hibernate 5.2 之前
? ? ? ? // SQLQuery sqlQuery = entityManager.createNativeQuery(sql).unwrap(NativeQueryImpl.class);
? ? ? ? // hibernate 5.2 之后的 寫法
?
? ? ? ? // unwrap 讓JPA的Query返回Map對象 javax.persistence.Query.unwrap
? ? ? ? // hibernate 或jpa 中使用 AliasToBeanResultTransformer 自定義類型轉(zhuǎn)換ResultTransformer 下劃線轉(zhuǎn)駝峰
? ? ? ? SQLQuery sqlQuery = entityManager.createNativeQuery(sql).unwrap(NativeQueryImpl.class);
? ? ? ? /*Query query =
? ? ? ? ? ? ? ? sqlQuery.setResultTransformer(Transformers.aliasToBean(NameOnlyDto.class));
? ? ? ? List<NameOnlyDto> list = query.getResultList();//.list();*/
?
? ? ? ? Query query =
? ? ? ? ? ? ? ? sqlQuery.setResultTransformer(Transformers.aliasToBean(NameOnlyDto.class));
?
? ? ? ? List<NameOnlyDto> ?list =query.getResultList();
? ? ? ? entityManager.clear();
? ? ? ? return list;
? ? }
}

public class NameOnlyDtoT implements Serializable {
? ? private ?String ?firstName;
? ? private ?String ?lastName;
? ? // private ?String ?address;
? ? private ?String ?sex;
? ? //構(gòu)造函數(shù) 特殊注意 這里返回幾個字段就要有幾個字段的構(gòu)造參數(shù) 感覺不太合適的地方
? ? public NameOnlyDtoT(String firstName, String lastName) {
? ? ? ? this.firstName = firstName;
? ? ? ? this.lastName = lastName;
? ? }
? ?/* public NameOnlyDtoT(String firstName, String lastName, String sex) {
? ? ? ? this.firstName = firstName;
? ? ? ? this.lastName = lastName;
? ? ? ? this.sex = sex;
? ? }*/
}

// 切記不能使用@query.如果使用@query 個人感覺和上面那種方法是一樣的邏輯
List<T> findByLastName(String lastname,Class<T> type);
? ? ? ? 使用（這里注意的是NameOnlyDtoT 中字段能賦值的只能是person中 含有的字段。這是個人覺得雞肋的存在）
? ? public ?List<NameOnlyDtoT> ?testNameOnlyDtoTS(){
? ? ? ? List<NameOnlyDtoT> ?nameOnlyDtoTS= personRepository.findByLastName("哈哈", NameOnlyDtoT.class);
? ? ? return nameOnlyDtoTS;
}

? ? ? ? <!-- web依賴 -->
? ? ? ? <dependency>
? ? ? ? ? ? <groupId>org.springframework.boot</groupId>
? ? ? ? ? ? <artifactId>spring-boot-starter-web</artifactId>
? ? ? ? </dependency>
? ? ? ? <!-- ?lombok依賴 -->
? ? ? ? <dependency>
? ? ? ? ? ? <groupId>org.projectlombok</groupId>
? ? ? ? ? ? <artifactId>lombok</artifactId>
? ? ? ? ? ? <version>1.18.8</version>
? ? ? ? </dependency>
? ? ? ? <!-- jpa依賴 -->
? ? ? ? <dependency>
? ? ? ? ? ? <groupId>org.springframework.boot</groupId>
? ? ? ? ? ? <artifactId>spring-boot-starter-data-jpa</artifactId>
? ? ? ? </dependency>
? ? ? ? <!-- mysql依賴 -->
? ? ? ? <dependency>
? ? ? ? ? ? <groupId>mysql</groupId>
? ? ? ? ? ? <artifactId>mysql-connector-java</artifactId>
? ? ? ? ? ? <scope>runtime</scope>
? ? ? ? </dependency>

server:
? port: 13333
spring:
? datasource:
? ? url: jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8&autoReconnect=true&serverTimezone=Asia/Shanghai&zeroDateTimeBehavior=convertToNull
? ? username: root
? ? password: 12345678
? ? driver-class-name: com.mysql.jdbc.Driver
? jpa:
? ? show-sql: true
? ? hibernate:
? ? ? ddl-auto: none

package com.lss.jpa.dao;
import com.lss.jpa.entity.dto.UserAddressDto;
import com.lss.jpa.entity.po.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import java.util.List;
import java.util.Map;
public interface UserDaoRepository extends JpaRepository<User, Integer> {
? ? @Query(value = "select \"title\" as common, u.id as id, u.name as name, a.id as addressId, a.address as addressName from user u, address a where u.id = a.user_id", nativeQuery = true)
? ? public List<UserAddressDto> findAllUserAddress();
? ? @Query(value = "select \"title\" as common, u.id as id, u.name as name, a.id as addressId, a.address as addressName from user u, address a where u.id = a.user_id and u.id=1", nativeQuery = true)
? ? public UserAddressDto findAllUserAddressById();
? ? @Query(value = "select \"title\" as common, u.id as id, u.name as name, a.id as addressId, a.address as addressName from user u, address a where u.id = a.user_id and u.id=1", nativeQuery = true)
? ? public Map<String, Object> findAllUserAddressByMap();
}

package com.lss.jpa.entity.dto;
public interface UserAddressDto {
? ? Integer getId();
? ? String getName();
? ? String getAddressName();
? ? Integer getAddressId();
? ? String getCommon();
}

package com.lss.jpa.web;
import com.lss.jpa.dao.UserDaoRepository;
import com.lss.jpa.entity.dto.UserAddressDto;
import com.lss.jpa.entity.po.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
import java.util.Map;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
@RestController
@Slf4j
public class TestController {
? ? @Autowired
? ? private UserDaoRepository userDaoRepository;
? ? @GetMapping("test")
? ? public String test(){
? ? ? ? List<UserAddressDto> all = userDaoRepository.findAllUserAddress();
? ? ? ? all.stream().forEach(dto -> {
? ? ? ? ? ? log.info("result: id:{}, name:{}, addressId:{}, addressName:{}, common:{}", dto.getId(), dto.getName(), dto.getAddressId(), dto.getAddressName(), dto.getCommon());
? ? ? ? });
? ? ? ? UserAddressDto dto = userDaoRepository.findAllUserAddressById();
? ? ? ? log.info("result: id:{}, name:{}, addressId:{}, addressName:{}, common:{}", dto.getId(), dto.getName(), dto.getAddressId(), dto.getAddressName(), dto.getCommon());
? ? ? ? Map<String, Object> map = userDaoRepository.findAllUserAddressByMap();
? ? ? ? log.info("map:{}", map);
? ? ? ? List<User> userList = userDaoRepository.findAll();
? ? ? ? log.info("userList:{}", userList);
? ? ? ? return "ok";
? ? }
}