巧用反照机制修改私有变量值
巧用反射机制修改私有变量值
为了演示如何利用反射机制来修改似有变量值,我在此先建一个类,只有一个私有变量,提供一个getter方法,代码如下:
package com.test.reflection; public class Test { private String str = "C++"; public String getStr() { return str; } }
为了将私有变量str里保存的值“C++”修改为“java”,我建立另一个测试类,代码如下:
package com.test.reflection; import java.lang.reflect.Field; public class Main { /** * @param args * @throws NoSuchFieldException * @throws SecurityException * @throws IllegalAccessException * @throws IllegalArgumentException */ public static void main(String[] args) throws SecurityException, NoSuchFieldException, IllegalArgumentException, IllegalAccessException { // TODO Auto-generated method stub Test test = new Test(); Class clacc = Test.class; Field field = clacc.getDeclaredField("str"); field.setAccessible(true);//设置true,使其不在检查访问修饰符。 field.set(test, "java"); System.out.println(test.getStr()); } }