重写持久化实体的hashCode()和equals()方法的正确方法是什么?

I have a simple class Role:

我有一个简单的类角色:

@Entity
@Table (name = "ROLE")
public class Role implements Serializable {

    @Id
    @GeneratedValue
    private Integer id;
    @Column
    private String roleName;

    public Role () { }

    public Role (String roleName) {
        this.roleName = roleName;
    }

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

    public Integer getId () {
        return id;
    }

    public void setRoleName (String roleName) {
        this.roleName = roleName;
    }

    public String getRoleName () {
        return roleName;
    }
}
@En