相关疑难解决方法(0)

我想检查实体是否在另一个实体的Collection成员(@OneToMany或@ManyToMany)中:

if (entity2.getEntities1().contains(entity1)) { }

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;
    }
}

现在我想覆盖它的方法equals和hashCode.我的第一个建议是:

public boolean equals (Object obj) {
    if …