package com.hibernate.model;import java.util.HashSet;import java.util.Set;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.JoinColumn;import javax.persistence.OneToMany;import javax.persistence.OneToOne;import javax.persistence.Table;@Entity@Table(name=_Group)public class Group {private int id;private String name;private Set

 <user>

   users = new HashSet

  <user>

   ();@Id@GeneratedValuepublic int getId() { return id;}public void setId(int id) { this.id = id;}public String getName() { return name;}@OneToMany(mappedBy=group)//双向的必须写上mappedBy,而且在数据库方面考虑，关联关系应该设计在多的一方，所以必须在OneToMany这方设mappedBypublic Set

   <user>

     getUsers() { return users;}public void setUsers(Set

    <user>

      users) { this.users = users;}public void setName(String name) { this.name = name;}}

    </user>

   </user>

  </user>

 </user>//源代码片段来自云代码http://yuncode.net

                       

 

package com.hibernate.model;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.ManyToOne;import javax.persistence.Table;@Entity@Table(name=_User)public class User {private int id;private String name;private Group group;@ManyToOnepublic Group getGroup() {        return group;}public void setGroup(Group group) {       this.group = group;}@Id@GeneratedValuepublic int getId() {      return id;}public void setId(int id) {  this.id = id;}public String getName() { return name;}public void setName(String name) { this.name = name;}}//源代码片段来自云代码http://yuncode.net