JPA 联合主键配置

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JPA 联合主键的配置，自己找了网上的一些写法，参考https://www.cnblogs.com/boywwj/p/8031106.html，https://baijiahao.baidu.com/s?id=1617918647119711819&wfr=spider&for=pc，有两种实现方式：1. 使用 @Embeddable   @EmbedId 注解   2. @IdClass  @Id  。第一种，需要在主实体类里面 声明一个被@Embeddable注释的类的对象 字段，并且此字段上需要加上  @EmbedId

@Embeddable
public class PeopleKey implements Serializable  {
     
    @Column(name = "name")
    private String name;
     
    @Column(name = "idcardno")
    private String idcardno;
    // 省略setter,getter方法
 
    @Override
    public String toString() {
        return "PeopleKey [name=" + name + ", idcardno=" + idcardno + "]";
    }
}　



@Entity
@Table(name = "people")
public class People extends PeopleKey{
　　　　// 复合主键要用这个注解
    @EmbeddedId
    private PeopleKey id;
 
    @Column(name = "age")
    private int age;

}

#摘自他人博客

编码过程中涉及到，对象dto 之间的copy ,上面写法就不友好了，自己摸索的写法，用@IdClass：

@MappedSuperclass
public class JobStatisticsKey implements Serializable{

    @Id
    @Column(name = "job_date")
    private String jobDate;

    @Id
    @Column(name = "worker_group")
    private String workerGroup;

   ##getter & setter 
   ## 参考别人博客要重写 hashCode & equals 方法，为什么，还有些疑问
}

@Entity
@Table(name = "t_job_statistics")
@IdClass(JobStatisticsKey.class)
public class JobStatistics extends JobStatisticsKey{

    @Column(name = "avg_exec_time")
    private BigDecimal avgExecTime;

    @Column(name = "avg_wait_time")
    private BigDecimal avgWaitTime;

    @Column(name = "max_exec_time")
    private Integer maxExecTime;
## getter  & setter 
}

还有一个需要注意就是 ,JpaRepository 的Id 泛型，写主键类JobStatisticsKey，我开始写的Long 也没报错，是没用到他的getOne或者deleteById方法:

@Repository
public interface JobStatisticsRepository extends JpaRepository<JobStatistics, JobStatisticsKey> {

    void deleteByJobDate(String jobDate);

    List<JobStatistics> findByJobDateBetween(String startTime ,String endTime);
}