spring - @CreationTimestamp 和 @UpdateTimestamp 在 Kotlin 中不起作用

Question

这是我的标签和帖子实体类:

@Entity
class Tag(
        @get:NotBlank
        @Column(unique = true)
        val name: String = "",
        val description: String = ""
) {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    val id: Int? = null


    @ManyToMany(mappedBy = "tags")
    val posts: MutableSet<Post> = mutableSetOf()

    @CreationTimestamp
    lateinit var createDate: Date

    @UpdateTimestamp
    lateinit var updateDate: Date

    fun addPost(post: Post) {
        this.posts.add(post)
        post.tags.add(this)
    }


}



@Entity
class Post(
        @get:NotBlank
        var name: String = "",
        val content: String = ""
) {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    val id: Int? = null
    @ManyToMany
    @Cascade(CascadeType.ALL)
    val tags: MutableSet<Tag> = mutableSetOf()

    @CreationTimestamp
    @Temporal(TemporalType.TIMESTAMP)
    lateinit var createDate: Date

    @UpdateTimestamp
    @Temporal(TemporalType.TIMESTAMP)
    lateinit var updateDate: Date


    fun addTag(tag: Tag) {
        this.tags.add(tag)
        tag.posts.add(this)
    }
}

查询:

val post1 = Post( "Post 1", "Post 1 content");
val post2 = Post( "Post 2", "Post 2 content");
var tag = Tag( "news", "Tag description")
post1.addTag(tag)
post2.addTag(tag)
em.persist(post1)
em.persist(post2)
em.remove(post1)
em.flush()

但是，createDate 和 updateDate 返回 null(标签和帖子):

我将此代码转换为 Java，它运行良好

Kotlin 版本:1.2-M2

springBoot版本:'2.0.0.M7'

Answer 1

问题可能存在于以下事实:这些注释并不限于它们应该注释的内容。这意味着 kotlin 并不确切知道将它们放在最终字节码中的何处。

要获得与 java 生成的字节码相同的字节码，您需要指定相关注释的注释目标:

@field:CreationTimestamp
lateinit var createDate: Date