我有两个表,用户和产品。我试图自动创建一个新的表TestedProducts,这是用户和产品之间的多对多关系。但是,我得到这个错误。
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看起来很不错。
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像这样:
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;
}
我跳过了其余的设置者和获取者。
最佳答案
您需要以与在用户实体中相同的方式注释产品实体中包含用户的列表,只是反向。我不认为mappedby值的处理方式相同。
关于java - JPA ManyToMany问题,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/10700683/