Hibernate中如何处理三张表关系

比如，我有一个User表，一个Project表，一个Role表。一个人可以在多个项目里面拥有多个角色。如何使用annotation来配置这样的关系？

[quote]人A，项目B,C,D，角色有E,F,G，这时候A在项目B上拥有角色E，在C上拥有F的角色。A在D项目也是角色E，你如何区分呢？你那样建立关系是没办法区分的。 [/quote]

那就是A拥有项目B,C,D

不明白你想表达的区分 是个什么概念

一个用户可以对应多个角色，一个角色可以对应多个项目
这样就可以达到你的一个一个人可以在多个项目里面拥有多个角色

[code="java"]/**

• */ package com.suziwen;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

/**

• @author suziwen

• @email suziwen1@gmail.com 2011-5-16
  */
  @Entity
  @Table(name = "k_user")
  public class User implements Serializable {

  private static final long serialVersionUID = 1L;
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "id", length = 22)
  private Long id;
  @ManyToMany
  @JoinTable(name = "k_user_role")
  private Set roles = new HashSet();
  public Long getId() {
  return id;
  }
  public void setId(Long id) {
  this.id = id;
  }
  public Set getRoles() {
  return roles;
  }
  public void setRoles(Set roles) {
  this.roles = roles;
  }
  }[/code]

[code="java"]/**

• */ package com.suziwen;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
import javax.persistence.OrderBy;
import javax.persistence.Table;

/**

• @author suziwen
• @email suziwen1@gmail.com

• 2011-5-16
  */
  @Entity
  @Table(name = "k_role")
  public class Role implements Serializable {

  private static final long serialVersionUID = 1L;

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "id", length = 22)
  private Long id;
  @ManyToMany(mappedBy = "roles")
  @OrderBy("id asc")
  private Set users = new HashSet();

  @ManyToMany(mappedBy = "roles")
  @OrderBy("id asc")
  private Set projects = new HashSet();

  public Long getId() {
  return id;
  }

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

  public Set getUsers() {
  return users;
  }

  public void setUsers(Set users) {
  this.users = users;
  }

  public Set getProjects() {
  return projects;
  }

  public void setProjects(Set projects) {
  this.projects = projects;
  }
  }[/code]
  [code="java"]
  /**

• */
  package com.suziwen;

import java.io.Serializable;
import java.util.Set;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.OrderBy;
import javax.persistence.Table;

/**

• @author suziwen
• @email suziwen1@gmail.com

• 2011-5-16
  */
  @Entity
  @Table(name = "k_project")
  public class Project implements Serializable {

  private static final long serialVersionUID = 1L;

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(name = "id", length = 22)
  private Long id;

  @ManyToMany
  @JoinTable(name="k_project_role")
  @OrderBy("id asc")
  private Set roles;

  public Long getId() {
  return id;
  }

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

  public Set getRoles() {
  return roles;
  }

  public void setRoles(Set roles) {
  this.roles = roles;
  }

}

[/code]

通过人找到角色，通过这些角色，找到这个人所对应的所有项目

[quote]人A，项目B,C,D，角色有E,F,G，这时候A在项目B上拥有角色E，在C上拥有F的角色。你如何区分呢？[/quote]

人A拥有角色E和F，E对应拥有的资源为项目B,F对应拥有的资源为项目C

如果你做项目的话，这不就和角色权限一样吗？