hibernate级联问题

Question

hibernate的级联:可不可以实现一个实体自身级联它自己啊？

Answer 1

of course it can!!!

Answer 2

public class City {
      .
      .
      .
      private City anotherCity;
      .
      .
      .
      @ManyToOne
      @JionColunm(name='anothercityid',referencedColumnName='id')
      public City getAnotherCity() {
            return anotherCity;
      }
      .
      .
}

Answer 3

我试了，还是报错，怎么弄啊？
这是pojo:
import java.util.Set;import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;@Entity
@Table(name ="t_city")
public class City { @Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int cityId;
private String name;
@OneToMany
@JoinColumn(name = "cityFId")
private Set<City> cities; @ManyToOne
@JoinColumn(name = "cityFId")
private City city;

public int getCityId() {
return cityId;
} public void setCityId(int cityId) {
this.cityId = cityId;
} public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} public Set<City> getCities() {
return cities;
} public void setCities(Set<City> cities) {
this.cities = cities;
}}