Spring Data REST：“没有String-argument构造函数/工厂方法从String值反序列化” [英] Spring Data REST: "no String-argument constructor/factory method to deserialize from String value"

问题描述

当我在Spring Data REST应用程序中使用Lombok来定义复杂类型时：

When I use Lombok in my Spring Data REST application to define complex types like:

@NoArgsConstructor
@AllArgsConstructor
@Data

@Entity
@Table(name = "BOOK")
public class Book {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(nullable = false)
    private Long id;

    private String title;

    @ManyToOne(cascade = {CascadeType.DETACH, CascadeType.MERGE, CascadeType.REFRESH})
    private Person author;

    // ...
}

春天数据REST控制器如：

with a Spring Data REST controllers like:

@RepositoryRestController
public class BookRepositoryRestController {

    private final BookRepository repository;

    @Autowired
    public BookRepositoryRestController(BookRepository repository) {
        this.repository = repository;
    }

    @RequestMapping(method = RequestMethod.POST,value = "/books")
    public @ResponseBody PersistentEntityResource post(
        @RequestBody Book book,
        PersistentEntityResourceAssembler assembler) {

        Book entity = processPost(book);

        return assembler.toResource(entity);
    }

    private Book processPost(Book book) {
        // ...
        return this.repository.save(book);
    }
}

我收到一个丑陋的错误：

I get an ugly error:

no String-argument constructor/factory method to deserialize from String value

来自Spring Data REST的

使用Jackson与Book POST一样：

from Spring Data REST's use of Jackson with a Book POST like:

curl -X POST 
     -H 'content-type: application/json' 
     -d '{"title":"Skip Like a Pro", "author": "/people/123"}'
     http://localhost:8080/api/books/

反序列化错误发生在Jackson尝试解析 / people / 123 本地URI，该URI应解析为单个唯一的 Person 。如果我删除 @RepositoryRestController ，一切正常。知道我的REST控制器定义有什么问题吗？

The de-serialization error happens when Jackson tries to resolve the /people/123 local URI which should resolve to a single, unique Person. If I remove my @RepositoryRestController, everything works fine. Any idea what's wrong with my REST controller definition?

推荐答案

在 @RepositoryRestController ，将 @RequestBody 参数的类型从 Book 更改为资源< ;预订> ：

In the @RepositoryRestController, change the type of the @RequestBody argument from Book to Resource<Book>:

import org.springframework.hateoas.Resource;

    // ...

    @RequestMapping(method = RequestMethod.POST,value = "/books")
    public @ResponseBody PersistentEntityResource post(
        @RequestBody Resource<Book> bookResource,             // Resource<Book>
        PersistentEntityResourceAssembler assembler) {

        Book book = bookResource.getContent()
        // ...
    }

以及 Book 实体定义将 AllArgsConstructor 注释修改为： @AllArgsConstructor（suppressConstructorProperties = true）。

and in the Book entity definition modify the AllArgsConstructor annotation to be: @AllArgsConstructor(suppressConstructorProperties = true).

有关详细信息，请参阅 Spring Data REST＃687 。

See Spring Data REST #687 for more information.

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