什么叫做自省

FastJson如何实现反序列时自省

https://en.wikipedia.org/wiki/Type_introspection

最近在使用到fastjson解析时遇到一个问题，我的类某个属性有多个子类，解析时如何识别到具体的子类呢，查阅了一些博客之后，发现fastjson有自省特性
只需要在被解析的JSON对象中添加@type:'FULL Class Path'即可实现指定类型解析
代码参考如下

public class School{
    private Teacher teacher;

    public School(Teacher teacher) {
        this.teacher = teacher;
    }

    public Teacher getTeacher() {
        return teacher;
    }

    public void setTeacher(Teacher teacher) {
        this.teacher = teacher;
    }
}

public class EnglishTeacher implements Teacher{
    public String myName() {
        return "英语老师";
    }
}
public class ChineseTeacher implements Teacher{
    public String myName() {
        return "语文老师";
    }
}

可以看到Teacher类有有个子类，如果要指定要解析成哪个子类，只需要在子json中添加@type属性即可

public class FastJsonTest {
    public static void main(String[] args) {


        School school = new School(new EnglishTeacher());
        System.out.println(JSON.toJSONString(school,SerializerFeature.WriteClassName));
        School schoolreverse = JSON.parseObject("{\"@type\":\"fastjsontest.School\",\"teacher\":{\"@type\":\"fastjsontest.EnglishTeacher\"}}",School.class);
        System.out.println(schoolreverse.getTeacher().myName());
    }
}