JPQL @query 与 json 的关系表

Question

我正在使用@Query 创建一个 JPQL 查询来获取 JSON 的关系数据列表

package thymeleaf.test.repository;

import java.util.List;

import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.rest.core.annotation.RepositoryRestResource;

import thymeleaf.test.model.Student;

@RepositoryRestResource
public interface StudentRepo extends CrudRepository<Student, Integer> {

    @Query("select s,t.teachName FROM Student s JOIN s.teacher t WHERE s.teacher.teachName= t.teachName")
    List<Student> findAll() ;
}

我得到了以下结果：

[
 [
   {
     "stuId": 1,
     "stuName": "Pawarut klai-armon                      ",
     "stuAge": 21
   },
   "sgkyrtgefewd                            "
 ]
]

我希望这个查询改为返回：

[
 {
   "stuId": 1,
   "stuName": "Pawarut klai-armon                      ",
   "stuAge": 21
   "teachName": "sgkyrtgefewd                            "
 }
]

Answer 1

您需要明确命名您要获取的字段，如下所示：

select s.stuId, s.stuName, s.stuAge, t.teachName FROM Student s JOIN s.teacher t WHERE s.teacher.teachName= t.teachName

如果您需要为字段命名，则需要像这样定义 DTO 对象：

class StuInfoWithTeacherName {
  private long id;
  private String stuName;
  private int stuAge;
  private String teacherName;
  public StuInfoWithTeacherName(id, stuName, stuAge, teacherName){
    //omitted
  }
}

比调用查询之类的

select new StuInfoWithTeacherName(s.stuId, s.stuName, s.stuAge, t.teachName) FROM Student s JOIN s.teacher t WHERE s.teacher.teachName= t.teachName