使用fastjson反序列化对象

liyongfei

Mar 1, 2022 • 2 min read

官方地址：https://github.com/alibaba/fastjson

// 见 https://github.com/alibaba/fastjson/wiki/JSONType_seeAlso_cn

@JSONType(seeAlso={Dog.class, Cat.class})
public static class Animal {
}

@JSONType(typeName = "dog")
public static class Dog extends Animal {
    public String dogName;
}

@JSONType(typeName = "cat")
public static class Cat extends Animal {
    public String catName;
}

// 使用
Dog dog = new Dog();
dog.dogName = "dog1001";

String text = JSON.toJSONString(dog, SerializerFeature.WriteClassName);
Assert.assertEquals("{\"@type\":\"dog\",\"dogName\":\"dog1001\"}", text);

Dog dog2 = (Dog) JSON.parseObject(text, Animal.class);

Assert.assertEquals(dog.dogName, dog2.dogName);

// 使用
Cat cat = new Cat();
cat.catName = "cat2001";

String text = JSON.toJSONString(cat, SerializerFeature.WriteClassName);
Assert.assertEquals("{\"@type\":\"cat\",\"catName\":\"cat2001\"}", text);

Cat cat2 = (Cat) JSON.parseObject(text, Animal.class);

Assert.assertEquals(cat.catName, cat2.catName);

对于抽象类反序列化，需要注意：

类要有 无参的构造函数
序列化时存储类型信息或者反序列化之前设置类型信息，即 JSON.toJSONString(dog, SerializerFeature.WriteClassName); 或者设置 @type
需要添加包的白名单以解决 com.alibaba.fastjson.JSONException: autoType is not support. xx.xxxx 错误，添加方式可使用全局配置 ParserConfig.getGlobalInstance().addAccept("包路径"); 具体可参考文章：解决com.alibaba.fastjson.JSONException: autoType is not support