在 POST/PUT 期间，所有对象的单个自定义反序列化器作为它们的 id 或嵌入的整个对象 [英] single custom deserializer for all objects as their ids or embedded whole objects during POST/PUT

问题描述

@Entity
public Product {
   @Id
   public int id;

   public String name;

   @ManyToOne(cascade = {CascadeType.DETACH} )
   Category category

   @ManyToMany(fetch = FetchType.EAGER, cascade = {CascadeType.DETACH} )
   Set<Category> secondaryCategories;


}

这个实体:

@Entity
public Category {
   @Id
   public int id;

   public String name;
}

我希望能够使用 json 发送 POST

I would like to be able to send a POST with json

{ name: "name", category: 2, secondaryCategories: [3,4,5] } 来自客户端

并且能够像这样反序列化:

and be able to be deserialized like:

{ name: "name", category: {id: 2 }, secondaryCategories: [{id: 3}, {id: 4}, {id: 5}] }

如果它被发送为

 { name: "name", category: {id: 2 }, secondaryCategories: [{id: 3}, {id: 4}, {id: 5}] }

我希望它仍然像现在一样工作

I would like it to still work as now

我需要什么样的注解和自定义反序列化器?希望反序列化器可以适用于所有可能具有 id 作为属性的对象

what kind of annotation and custom deserializer I need? Hopefully the deserializer can work for all possible objects that have id as a property

谢谢！

编辑

• 查看首选 zafrost 的 @JsonCreator 答案(https://stackoverflow.com/a/46618366/986160)
• 查看我的完整答案 (https://stackoverflow.com/a/46618193/986160) 以扩展 StdDeserializer 并通过 ObjectMapper
使用默认反序列化

• See the preferred zafrost's @JsonCreator answer (https://stackoverflow.com/a/46618366/986160)
• See my complete answer (https://stackoverflow.com/a/46618193/986160) for extending StdDeserializer and using default deserialization through ObjectMapper

推荐答案

如果可以修改实体，另一种方法是使用 @JsonCreator 工厂方法

Another approach is to use @JsonCreator factory method if you can modify your Entity

private class Product {
    @JsonProperty("category")
    private Category category;

    @JsonProperty("secondaryCategories")
    private List<Category> secondaryCategories;
}


private class Category {
    @JsonProperty("id")
    private int id;

    @JsonCreator
    public static Category factory(int id){
        Category p = new Category();
        p.id = id;
        // or some db call 
        return p;
    }
}

甚至这样的东西也应该可以工作

Or even something like this should also work

private class Category {
    private int id;

    public Category() {}

    @JsonCreator
    public Category(int id) {
        this.id = id;
    }
}

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