通过反射得到一个类的对象，如何对该对象对应的类的父类中的变量赋值？

[长耳bunny]

如题所述，下面是例子：

class  Person{  
    private int age;  
    private String name;  
    public Person(){  
          
    }  
    public Person(int age, String name){  
        this.age = age;  
        this.name = name;  
    }  
  
    public int getAge() {  
        return age;  
    }  
    public void setAge(int age) {  
        this.age = age;  
    }  
    public String getName() {  
        return name;  
    }  
    public void setName(String name) {  
        this.name = name;  
    }  
}  
  
class SuperMan extends Person implements ActionInterface  
{  
    private boolean BlueBriefs;  
      
    public static void fly()  
    {  
        System.out.println("超人会飞耶～～");  
    }  
      
    public boolean isBlueBriefs() {  
        return BlueBriefs;  
    }  
    public void setBlueBriefs(boolean blueBriefs) {  
        BlueBriefs = blueBriefs;  
    }  
  
    @Override  
    public void walk(int m) {  
        // TODO Auto-generated method stub  
        System.out.println("超人会走耶～～走了" + m + "米就走不动了！");  
    }  
}  
interface ActionInterface{ 
	public static int nonono = 1;
    public void walk(int m);  
}  

接下来是主函数：

public static void main(String[] args) throws Exception {
		Class<?> clazz = null;
		clazz = Class.forName("bianchengzhimei.SuperMan");
		
		Object p1 = clazz.newInstance();
		Field personNameField = clazz.getDeclaredField("name");
		personNameField.setAccessible(true);
		personNameField.set(p1, "darlingFish");

		System.out.println(personNameField.get(p1));

这样的话程序会出错误：
Exception in thread "main" java.lang.NoSuchFieldException: name
at java.lang.Class.getDeclaredField(Class.java:2057)
at bianchengzhimei.ZDGYSP151.main(ZDGYSP151.java:32)
问题的原因是getDeclaredField()只能获取出该类的变量（不包括继承自父类的变量），那么问题出现了，如何对父类中的变量赋值呢？？？？？

[长耳bunny]

刚刚又看到一个方法，getFields，本以为能把集成的变量都找出来，结果不好使

[长耳bunny]

引用 2 楼 u011278496 的回复:

Person person = new Person(10, "LL");
        try {
            Field field = person.getClass().getDeclaredField("name");
            field.setAccessible(true);

            field.set(person, "ERWA");
            
            System.out.println(person.getName());
        } catch (NoSuchFieldException | IllegalAccessException e) {
            e.printStackTrace();
        }

要什么就反射取吧

我的意思是SuperMan的实例，想通过反射得到SuperMan父类Person的变量。。。

[jacob_cxt]

getdeclaredfields应该是不行的, 它好像只能得到当前类所有属性 getfields按理应该可以获取到当前类极其父类的所有属性, 当然前提是属性得是public的

[2.wa]

Person person = new Person(10, "LL");
        try {
            Field field = person.getClass().getDeclaredField("name");
            field.setAccessible(true);

            field.set(person, "ERWA");
            
            System.out.println(person.getName());
        } catch (NoSuchFieldException | IllegalAccessException e) {
            e.printStackTrace();
        }

要什么就反射取吧

[福来哥]

7楼的方法基本上可以用了。另外推荐一种更规范的写法：

Class<?> clazz = null;
	    clazz = Class.forName("bianchengzhimei.SuperMan");
		//使用符合JavaBean规范的属性访问器
	    PropertyDescriptor pd = new PropertyDescriptor("name", clazz);
		//调用setter		
		Method writeMethod = pd.getWriteMethod();	//setName()
		writeMethod.invoke(obj, "test");
		//调用getter
		Method readMethod = pd.getReadMethod();		//getName()
		readMethod.invoke(obj);

[bayougeng]

private是私有变量，如果想给子类用，你就应该定义成protected啊。 否则要这么多访问限定关键字干什么

[2.wa]

SuperMan superMan = new SuperMan(10, "LL");
        try {
            //Field field = person.getClass().getDeclaredField("name");
            Field field =  superMan.getClass().getSuperclass().getDeclaredField("name");
            field.setAccessible(true);
            field.set(superMan, "ERWA");
            System.out.println(superMan.getName());
        } catch (NoSuchFieldException | IllegalAccessException e) {
            e.printStackTrace();
        }

可以取到自己，再取个父类不就 OK?

[dellmysky]

	public static void main(String[] args) throws Exception {
		Class<?> clazz = null;
		clazz = Class.forName("bianchengzhimei.SuperMan");
		Object p1 = clazz.newInstance();
		Field personNameField = null;
	    for(;clazz != Object.class;clazz= clazz.getSuperclass()){
	    	try {
				personNameField = clazz.getDeclaredField("name");
			} catch (Exception e) {}
	    }
	    personNameField.setAccessible(true);
		personNameField.set(p1, "darlingFish");

		System.out.println(personNameField.get(p1));
	}