java - 将 transient 属性映射到别名 - Spring JPA

Question

在 Spring JPA 中是否可以将对象的 Transient 属性映射到这样的别名？

native 查询

SELECT *, 1 AS liked FROM User WHERE user_id = 123 // + logic to determine if liked

类

@Entity
public class User {

    @Id
    private Long userId;

    @Column(name = "displayName")
    private String displayName;

    @Transient
    private int liked; // not tied to any column

}

我尝试实现这个，但 liked 总是返回 0，而它应该是 1(如果我将该字段定义为对象类型，则返回 null)

感谢任何帮助!

Answer 1

您应该对该字段使用 @Formula 注释(请参阅 the example )

The @Formula annotation to provide an SQL snippet which Hibernate will execute when it fetches the entity from the database. The return value of the SQL snippet gets mapped to a read-only entity attribute.