JSON、Jersey 和 Jackson 中的多态性 [英] Polymorphism in JSON, Jersey and Jackson

问题描述

Jackson with Jersey 是否支持基于 JSON 的多态类?

Does Jackson with Jersey support polymorphic classes over JSON?

例如，假设我有一个 Parent 类和一个继承自它的 Child 类.而且，假设我想使用 JSON 发送 &通过 HTTP 接收父级和子级.

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 {
...
}

我考虑过这种实现方式:

I've thought about this kind of implementation:

@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?Child 的额外成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&回应.

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.

顺便说一句，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，

Jackson does support polymorphism,

在您的子类中使用名称进行注释:

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:

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

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