JSON，泽西岛和杰克逊的多态性 [英] Polymorphism in JSON, Jersey and Jackson

问题描述

Jackson和Jersey支持多态类而不是JSON吗？

Does Jackson with Jersey support polymorphic classes over JSON?

比方说，我有一个Parent类和一个继承它的Child类。而且，假设我想使用JSON发送&通过HTTP接收父母和子女。

Let's say, for instance, that I've got a Parent class and a Child class that inherits from it. And, let's say I want to use JSON to send & receive both Parent and Child over HTTP.

public class Parent {
...
}

public class Child extends Parent {
...
}

我考虑过这种实现：

@Consumes({ "application/json" }) // This method supposed to get a parent, enhance it and return it back
    public @ResponseBody 
    Parent enhance(@RequestBody Parent parent) {
    ...
    }

问题：如果我给这个函数（当然是通过JSON）一个Child对象，它会起作用吗？孩子的额外会员字段也会被序列化吗？
基本上，我想知道这些框架是否支持多态消费&回复。

Question: If I give this function (through JSON of course) a Child object, will it work? Will the Child's extra member fields be serialized, as well ? Basically, I want to know if these frameworks support polymorphic consume & respond.

BTW，我正在使用Spring MVC。

BTW, I'm working with Spring MVC.

推荐答案

Jackson确实支持多态性，

Jackson does support polymorphism,

在您的子类中使用名称注释：

In your child class annotate with a name:

 @JsonTypeName("Child_Class")
 @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "objectType")
 public class Child extends Parent{
 ....
 }

在父级中指定子类型：

In parent you specify sub types:

@JsonSubTypes({ @JsonSubTypes.Type(value = Child.class), @JsonSubTypes.Type(value = SomeOther.class)}) 
public class Parent {
    ....
}

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