找不到类型为：java.lang.Long的验证器.帖子ID

HTTP Status 500 - Request processing failed; nested exception is javax.validation.UnexpectedTypeException: HV000030: No validator could be found for type: java.lang.Long.

并且不知道如何解决它…在堆栈跟踪中,我编写的唯一类是

myapp.spring.controllers.PostFormController.processForm(PostFormController.java:66)

这条线是

validator.validate(p,result);

Post.java

// imports

@Entity
@Table(name="posts")
public class Post implements Serializable
{
        /* **********************************
         * ------------ fields ------------ *
         ************************************/
        /**
         *
         */
        private static final long serialVersionUID = 1L;

        @Id
        @GeneratedValue(strategy=GenerationType.IDENTITY)
        private long id;

        @Past
        @Column(name="date")
        private Date date;

        @NotBlank
        @Size(min=3,max=20)
        @Column(name="author")
        private String author;

        @NotBlank
        @Column(name="content")
        private String content;

        @NotBlank
        @Column(name="topic")
        private String topic;

        @NotBlank
        @Column(name="thread_id")
        private long thread_id;

        @ManyToOne
        @JoinColumn(name="name")
        @Valid
        private PostType type;



        /* ***************************************
         * ---------- getters setters ---------- *
         *****************************************/
       // cut // 

}

blah blah blah无法添加因为帖子中的代码太多：S