Spring Boot在json响应中包含OneToMany关联

Question

我有一个实体

@Entity
public class Post {
    @Id
    private Long id;

    @NotNull
    private Date createdAt;

    @NotNull
    private String text;

    @NotNull
    private Date updatedAt;

    @OneToMany
    private List<Comment> comments;
}

和另一个实体

@Entity
public class Comment {
    @Id
    private Long id;

    @NotNull
    private Date createdAt;

    @NotNull
    private String text;

    @NotNull
    private Date updatedAt;
}

我有一个简单的控制器，返回给定id的post json

    @RestController
    @RequestMapping("/posts")
    public class ProductDimensionsController {

    @RequestMapping(method = RequestMethod.GET)
    public Post getPost(@RequestParam(value = "id") String id) throws ApiException {
        ...
        ...
        ...
    }
}

我得到回应：

{
"id": 401,
"createdAt": 1482364510614,
"updatedAt": 1482364510614,
"text": "abc",
}

我要关注：

{
"id": 401,
"createdAt": 1482364510614,
"updatedAt": 1482364510614,
"text": "abc",
"comments": [{
    "id": 101,
    "createdAt": 1482364510614,
    "updatedAt": 1482364510614,
    "text": "xyz",
    }]
}

如何在json响应中包含关联的OneToMany实体？

Answer 1

为了获得所需的结果，您必须在Comment实体上标记@ManyToOne(fetch = FetchType.LAZY) 。 这将导致以FetchType.LAZY模式获取结果。

另一种方法可能是：

@Entity
public class Post {
    @Id
    private Long id;

    @NotNull
    private Date createdAt;

    @NotNull
    private String text;

    @NotNull
    private Date updatedAt;

    @OneToMany
    @JsonIgnore
    private List<Comment> comments;

    @JsonIgnore
    public List<Comment> getComments() {
        return comments;
    }

    @JsonProperty
    public void setComments(List<Comment> comments) {
        this.comments = comments;
    }
}