复合主键误差

Question

我想做一张桌子，让我们假设桌子的名字是汽车。它将有3列，brandId，typeId和sizeId。我希望所有的列都是主键。typeId和sizeId是来自不同表的列。我已经尝试编写代码，但是如果我对每一列使用注释@Id，错误将出现“没有找到超级类型”。

代码在下面。

@Entity
@Table(name = "CAR")
public class Car implements Serializable {
  private static final long serialVersionUID = -1576946068763487642L;

  @Id
  @Column(name = "BRAND_ID", nullable = false, length = 20)
  private String brandId;

  @Id
  @ManyToOne
  @JoinColumn(name = "TYPE_ID", nullable = false)
  private TypeId typeId;

  @Id
  @ManyToOne
  @JoinColumn(name = "SIZE_ID", nullable = false)
  private SizeId sizeId;



  public String getBrandId() {
      return brandId;
  }

  public void setBrandId(String brandId) {
      this.brandId= brandId;
  }


  public TypeId getTypeId() {
      return typeId;
  }

  public void setTypeId (TypeId typeId) {
      this.typeId= typeId;
  }


  public SizeId getSizeId() {
      return sizeId;
  }

  public void setSizeId (SizeId sizeId) {
      this.sizeId= sizeId;
  }

}

因此，我搜索并发现我可以使用@EmbeddedId创建复合主键。实体的代码如下：

@Entity
@Table(name = "CAR")
public class Car implements Serializable {
  private static final long serialVersionUID = -1576946068763487642L;

  @EmbeddedId
  private CarPk carPk;


  public CarPk getCarPk () {
      return carPk ;
  }

  public void setCarPk (CarPk carPk ) {
      this.carPk = carPk ;
  }

}

和可嵌入类：

@Embeddable
public class CarPk implements Serializable {
  private static final long serialVersionUID = -83738833L;


  @Column(name = "BRAND_ID", nullable = false, length = 20)
  private String brandId;


  @ManyToOne
  @JoinColumn(name = "TYPE_ID", nullable = false)
  private TypeId typeId;


  @ManyToOne
  @JoinColumn(name = "SIZE_ID", nullable = false)
  private SizeId sizeId;

  public String getBrandId() {
      return brandId;
  }

  public void setBrandId(String brandId) {
      this.brandId= brandId;
  }


  public TypeId getTypeId() {
      return typeId;
  }

  public void setTypeId (TypeId typeId) {
      this.typeId= typeId;
  }


  public SizeId getSizeId() {
      return sizeId;
  }

  public void setSizeId (SizeId sizeId) {
      this.sizeId= sizeId;
  }
}

然后，我想创建基于brandId的查找列的接口。接口代码：

public interface CardDao extends PagingAndSortingRepository<Car, Long>, QueryDslPredicateExecutor<Car> {
     public Car findByBrandId(String brandId);
}

不幸的是，代码是错误的：

“无法根据路径解析属性brandId”。

因此，我在实体类中为brandId创建了setter getter :

@Entity
@Table(name = "CAR")
public class Car implements Serializable {
  private static final long serialVersionUID = -1576946068763487642L;

  @EmbeddedId
  private CarPk carPk;


  public CarPk getCarPk () {
      return carPk ;
  }

  public void setCarPk (CarPk carPk ) {
      this.carPk = carPk ;
  }

  public brandId getBrandId (){
      return carPk.getBrandId();
  }

  public void setBrandId (String brandId){
      this.carPk.setBrandId(brandId);
  }
}

错误不会出现，但是表的car的数据也不会出现。

我的问题是：

1. 接口代码是真的吗？当brandId的列在brandId类中时，我想知道是否可以通过Embeddable找到它。
2. 实体类中用于brandId的setter是否为true？

谢谢!

Answer 1

你有一个复合主键。见复合主键。