java - fastjson在反序列化时,怎么解析对象中的继承

Question

例子:

import com.alibaba.fastjson.JSON;

public class Text {

    private A a;

    class A {

        private String a;

        public String getA() {
            return a;
        }

        public void setA(String a) {
            this.a = a;
        }

    }

    class B extends A {

        private String b;

        public String getB() {
            return b;
        }

        public void setB(String b) {
            this.b = b;
        }

    }

    public A getA() {
        return a;
    }

    public void setA(A a) {
        this.a = a;
    }

    public static void main(String[] args) {
        Text text = new Text();

        B b = text.new B();
        b.setA("aaaaa");
        b.setB("bbbbb");

        text.setA(b);

        String ttt = JSON.toJSONString(text);
        System.out.println(ttt);
        Text text2 = JSON.parseObject(ttt, Text.class);

        System.out.println(JSON.toJSONString(text2));
    }
    }

这里的输出结果分别是:
{"a":{"a":"aaaaa","b":"bbbbb"}}
{"a":{"a":"aaaaa"}}
在第二次反序列化时候,由于Text对象中A存在继承关系。所以出现信息丢失。请问fastjson中是否有对应的办法解决这个问题?

Answer 1

private A a;

改成

private B a;

就可以

Answer 2

 SerializerFeature[] features = new SerializerFeature[] {
                SerializerFeature.WriteClassName,
                //SerializerFeature.SkipTransientField,
                //SerializerFeature.DisableCircularReferenceDetect
 };

String ttt = JSON.toJSONString(text, features);
System.out.println(ttt);
Text text2 = JSON.parseObject(ttt, Text.class);

System.out.println(JSON.toJSONString(text2));

子类转父类，泛型等，可以通过WriteClassName这个feature，这样json里会有@type标注真是的类