JavaSE 反射（进阶） 反射操纵private函数

一.getDeclareMethod 不同于getMethod 方法，后者只能操纵public函数，而前者凡是declare声明过的函数都能被操纵。

二.

public void setAccessible(boolean flag) throws SecurityException 方法解释：

该方法为Method Constructor Field类的父类AccessibleObject定义的方法。

引入JDK的原话：(Quote from JDK)

Set the accessible flag for this object to the indicated boolean value.
A value of true indicates that the reflected object should suppressJava language access checking when it is used.

设置object.setAccessible(true)意味着压制java的访问规则。

A value of false indicates that the reflected object should enforce Java language access checks. 

设置object.setAccessible(false)意味着强制执行java的访问规则。 

三. 下面为一个具体实例，展示如何用反射reflection机制来 操纵一个类的private函数：

package com.java.reflection;public class PrivateReflect {private String feedback(String str)  //等待被操纵的private函数{return "Hello "+str;}}

package com.java.reflection;import java.lang.reflect.Method;public class PrivateTest {public static void main(String[] args) throws Exception {Class<?> classType=PrivateReflect.class;Object p=classType.newInstance();Method method=classType.getDeclaredMethod("feedback",String.class);//Set the accessible flag for this object to the indicated boolean value.//A value of true indicates that the reflected object should suppress Java language access checking when it is used. //A value of false indicates that the reflected object should enforce Java language access checks.                 method.setAccessible(true);String str=(String)method.invoke(p,"Ma Yun");System.out.println(str);}}

输出：

Hello Ma Yun