JPA ManyToMany问题

Question

我有两个表，用户和产品。我试图自动创建一个新的Table TestedProducts，这是用户和产品之间的多对多关系。但是，我收到了这个错误。

org.apache.jasper.JasperException: javax.ejb.EJBException: The bean encountered a non-application exception; nested exception is: 
<openjpa-1.2.1-r752877:753278 fatal user error> org.apache.openjpa.persistence.ArgumentException: 
"ejb.UserEntity.products<element:interface ejb.Product>" has columns with targets, but OpenJPA does not support any joins on this mapping in this context.

UserEntity看起来很精简。

long id;

String firstname;
String lastname;
String password;
String email;
String description;

List<Product> products;

public void setId(long id){
    this.id = id;
}

@Id
@GeneratedValue
public long getId() {
    return id;
}

@ManyToMany
@JoinTable(name="TestedProducts", 
joinColumns=
    @JoinColumn(name="usrId", referencedColumnName="id"),
  inverseJoinColumns=
  @JoinColumn(name="prodId", referencedColumnName="id")
  )
  public List<Product> getProducts() {
    return products;
  }

  public void setProducts(List<Product> products) {
    this.products = products;
  }

和ProductEntity这样：

long id;

String name;
String description;
String type;

List<User> users;

@ManyToMany(mappedBy="products") 
protected List<User> getUsers() {
    return users;
}

protected void setUsers(List<User> users) {
this.users = users;
}

我跳过其他的二传手和吸气鬼。

Answer 1

您需要以与在用户实体中相同的方式注释包含产品实体中用户的列表，仅反转。我不认为mappedby值处理相同。