Java访问类中private属性和方法
Java访问类中private属性和方法
一般在其他类中是不能这个得到类中private属性和访问private方法的,但天无绝人之路,java强大的反射机制可以完成这个任务。建一个测试类A:
- package com.shao.test;
- public class A {
- private String testStr="just for test";
- private void get(int index,String value){
- System.out.println(index+":"+value+" and testStr:"+testStr);
- }
- }
现在我们来访问A中的testStr属性和get方法:
- package com.shao.test;
- import java.lang.reflect.Field;
- import java.lang.reflect.InvocationTargetException;
- import java.lang.reflect.Method;
- public class B {
- public static void main(String[]args) throws ClassNotFoundException, NoSuchFieldException, IllegalArgumentException, IllegalAccessException, NoSuchMethodException, InvocationTargetException{
- Field field=Class.forName("com.shao.test.A").getDeclaredField("testStr");
- field.setAccessible(true);
- A a=new A();
- System.out.println(field.getType().toString()); //print:class java.lang.String
- System.out.println(field.getName()); //print:testStr
- System.out.println(field.getModifiers()); //print:2
- Object s=field.get(a);
- System.out.println(s); //print:just for test
- String x="Hello";
- field.set(a, x);
- System.out.println(field.get(a)); //print:Hello
- Method method=Class.forName("com.shao.test.A").getDeclaredMethod("get", new Class[]{int.class,String.class});
- method.setAccessible(true);
- method.invoke(a, 3,"apples"); //print:3:apples and testStr:Hello
- }
- }
评论暂时关闭