java - JPA : reference to a generated JoinTable

Question

我有两个实体:产品和过道。一种产品可以位于一个或多个过道中，并且一个过道可以有一个或多个产品。

@Entity 
public class Product{
   @Id
   private Long id;
   private String name;
   @ManyToMany
   @JoinTable(name = "product_aisle",
            joinColumns = { @JoinColumn(name = "product_id") },
            inverseJoinColumns = { @JoinColumn(name = "aisle_id") })
    private Set<Aisle> aisles = new HashSet<>();
   /* getters, setters, equals and hashcode */
}


@Entity 
public class Aisle{
   @Id
   private Long id;
   private String row;
   private String shelf;
   @ManyToMany(mappedBy="aisles")
   private Set<Product> products = new HashSet<>();
   /* getters, setters, equals and hashcode */
}

我还有最后一个实体:推销员。销售员负责过道上的产品:

@Entity 
public class Salesman{
   @Id
   private Long id;

   private String name;

   /* ManyToOne to  ProductAisle ?*/

}

问题:如何使用“@ManyToOne”注释将销售员引用到自动创建的联接表 (ProductAisle)？

问候

Answer 1

要表示位于特定 channel 中的产品，您需要另一个实体。这是一个例子:

@Entity 
public class Product{
   @Id
   private Long id;
   private String name;
   @OneToMany(mappedBy = "product")
   private Set<ProductAisle> productAisle = new HashSet<>;
   /* getters, setters, equals and hashcode */
}


@Entity 
public class Aisle{
   @Id
   private Long id;
   private String row;
   private String shelf;
   @OneToMany(mappedBy = "aisle")
   private Set<ProductAisle> productAisle = new HashSet<>();
   /* getters, setters, equals and hashcode */
}

@Entity 
public class ProductAisle{
   @Id
   private Long id;
   @ManyToOne(fetch = FetchType.LAZY)
   private Product product;
   @ManyToOne(fetch = FetchType.LAZY)
   private Aisle aisle;
   /* getters, setters, equals and hashcode */
}

然后您的 Salesman 将指向 ProductAisle 实例的集合，该实例将产品与过道映射:

@Entity 
public class Salesman{
   @Id
   private Long id;

   private String name;

   @ManyToOne(fetch = FetchType.LAZY)
   private Set<ProductAisle> productAisle;

}