关于JPA注解 @index 为什么会报错 ？ not applicable to filed ?

Question

如下图： 为什么会这样 ？

Answer 1

看看这个：stackoverflow

不同的JPA版本，用法略有区别。因为你也没说你是什么版本，只能给出原帖，自己对照了

还有，你的Index类，引入对了么？import javax.persistence.Index;

Answer 2

亲，你要去看看 @Index 的定义及其使用。请参考下面的例子吧：

import java.util.*
import javax.persistence.*

@Entity
@Table(indexes = arrayOf(
        Index(name = "idx_url", unique = true, columnList = "url"),
        Index(name = "idx_category", unique = false, columnList = "category")))
class Image {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    var id: Long = -1
    @Version
    var version: Int = 0
    var category: String = ""
    var isFavorite: Int = 0
    var url: String = ""

    var gmtCreated: Date = Date()
    var gmtModified: Date = Date()
    var isDeleted: Int = 0  //1 Yes 0 No
    var deletedDate: Date = Date()

    override fun toString(): String {
        return "Image(id=$id, version=$version, category='$category', isFavorite=$isFavorite, url='$url', gmtCreated=$gmtCreated, gmtModified=$gmtModified, isDeleted=$isDeleted, deletedDate=$deletedDate)"
    }
}