JPA 一对多单向 映射至Mysql的问题

Question

角色Role与权限Authority，我设计成一对多单向关联，数据库mysql：

//Role.java：

@Entity
public class Role implements Serializable {
    private Integer roleid;
    private String rolename;
    private String description;
    private Set<Authority> auths = new HashSet<Authority>();
    
    @Column
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    @Id
    @GeneratedValue
    public Integer getRoleid() {
        return roleid;
    }
    public void setRoleid(Integer roleid) {
        this.roleid = roleid;
    }
    @Column
    public String getRolename() {
        return rolename;
    }
    public void setRolename(String rolename) {
        this.rolename = rolename;
    }
         //一对多单向关联
    @OneToMany(cascade = CascadeType.REFRESH, fetch=FetchType.EAGER)
    @JoinTable(name = "role_auth", joinColumns = @JoinColumn(name = "roleid"), 
            inverseJoinColumns = @JoinColumn(name = "authorityid"))
    public Set<Authority> getAuths() {
        return auths;
    }
    public void setAuths(Set<Authority> auths) {
        this.auths = auths;
    }
    
    // 添加权限
    public void addAuth(Authority auth) {
        this.auths.add(auth);
    }
    
    @Override 
    public int hashCode() {
        ...
    }
    
    @Override
    public boolean equals(Object obj) {
        ...
    }
}

//Authority.java：

@Entity
public class Authority implements Serializable {
    private Integer authorityid;
    // 范围
    private Range range;
    // 动作
    private Action action;
    
    public Authority() {}
    
    public Authority(Range range, Action action) {
        this.range = range;
        this.action = action;
    }
    
    @ManyToOne
    @JoinColumn(name="actionid", 
            referencedColumnName="actionid")
    public Action getAction() {
        return action;
    }
    public void setAction(Action action) {
        this.action = action;
    }
    @Id
    @GeneratedValue
    public Integer getAuthorityid() {
        return authorityid;
    }
    public void setAuthorityid(Integer authorityid) {
        this.authorityid = authorityid;
    }
    @ManyToOne
    @JoinColumn(name="rangeid", 
            referencedColumnName="rangeid")
    public Range getRange() {
        return range;
    }
    public void setRange(Range range) {
        this.range = range;
    }
    
    @Override 
    public int hashCode() {
        ...
    }
    
    @Override
    public boolean equals(Object obj) {
        ...
    }
    
}

生成的中间表为role_auth，查看建表语句：

mysql> show create table user_role;

| Table     | Create Table
| user_role | CREATE TABLE `user_role` (
  `userid` int(11) NOT NULL,
  `roleid` int(11) NOT NULL,
  PRIMARY KEY  (`userid`,`roleid`),
  UNIQUE KEY `roleid` (`roleid`),//roleid为什么具有唯一性？？？
  KEY `FK143BF46A889EC6EB` (`userid`),
  KEY `FK143BF46A83497181` (`roleid`),
  CONSTRAINT `FK143BF46A83497181` FOREIGN KEY (`roleid`) REFERENCES `role` (`rol
eid`),
  CONSTRAINT `FK143BF46A889EC6EB` FOREIGN KEY (`userid`) REFERENCES `user` (`use
rid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |

1 row in set (0.00 sec)

如上红色部分，roleid具有唯一性，这样我在插入角色时就会出现类似“Duplicate entry '2' for key 2”的错误。
该怎么改呢？？

 

Answer 1

[b]好看点：[/b]

[code="java"]public class Authority implements Serializable {
// 这个int型的id，是（似乎）JPA规范要求的。被JPA的Provider用来检测
// 某个具体的对象的状态时，使用的。
// 所以，每个Entity都要有一个int型的id
// 如果id相同，即证明是同一个对象，即同一条记录，所以不允许相同
// 故，常用于作 主键
private int id;

// 这个id就是 你实际业务要用到的id，当然可以按照你的需要设为 unique或者
// 非 unique
private intauthorityid;

//....省略 ....
}[/code]