从json赋值后打印类的属性时获取null

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

public class MyClass {
    private String name;
    private Integer age;

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public Integer getAge() {
        return age;
    }

    public static void main(String[] args) {
        String jsonString = "{\"name\": \"John\", \"age\": null}";

        MyClass myClass = new MyClass();
        JSONObject json = JSON.parseObject(jsonString);

        if (json.containsKey("name") && json.getString("name") != null) {
            myClass.setName(json.getString("name"));
        }

        if (json.containsKey("age") && json.getInteger("age") != null) {
            myClass.setAge(json.getInteger("age"));
        }

        System.out.println("Name: " + myClass.getName()); // 输出：Name: John
        System.out.println("Age: " + myClass.getAge()); // 输出：Age: null
    }
}