JPA的关联对象查询

记录一种有趣的JPA的关联对象查询方式。

代码如下：

    /*
     *  这是一个dto 
     */
    public class WorkSeries {

        private Integer id;

        private String workName;

        private String seriesName;

        public WorkSeries() {
        }

        public WorkSeries(Integer id, String workName, String seriesName) {
            this.id = id;
            this.workName = workName;
            this.seriesName = seriesName;
        }

        //get、set省略
    }

    /*
     *  然后是两个实体
     */
    @Entity
    public class Series {

        @Id
        @GeneratedValue
        private Integer id;

        private String name;

        //get、set省略    
    }

    @Entity
    public class Work {

        @Id
        @GeneratedValue
        private Integer id;

        private String name;

        //get、set省略    
    }

    /*
     *  最后一个JPA查询
     */
    public interface WorkRepository extends JpaRepository<Work, Integer> {
        
        @Query("SELECT new com.miaostar.dto.WorkSeries(work.id,work.name,series.name) FROM Work work,Series series")
        List<WorkSeries> findWorkSeries();

    }

参考:

1. SpringBoot第八讲Spring Data JPA的关联对象查询