Question

项目有两个实体：

@Entity
public class Customer {
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id", unique = true, nullable = false)
private Integer id;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "city_id", nullable = true)
private City city;
...
}

和

@Entity
public class City {
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id", unique = true, nullable = false)
private Integer id;

@Column(name = "name", nullable = false)
private String name;
...
}

使用Gson或Jackson转换为JSON的Cutomer实体转换为

{
"id":1,
"city":{"id":1, "name":"New York"}
}

我希望它转换为

{
"id":1,
"city_id":1
}

我怎么能通过gson或jackson做到这一点？

Answer 1

这个问题可能对您有所帮助。

Gson: How to exclude specific fields from Serialization without annotations

我不知道是否有直接的方法可以实现这一目标，但也有间接的方式可以完成。例如，您可以将private City city标记为transient，然后您可以公开另一个名为city_id的字段，该字段只是城市ID。它看起来像这样：

@Entity
public class Customer {
    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    private Integer id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "city_id", nullable = true)
    private transient City city;

    private int city_id;
    ...
}

将hibernate实体转换为JSON：oblectId而不是整个对象

1 个答案: