JAVA 反射

使用JAVA反射示例，反射修改字段属性值和方法参数

public class ReflectionTest {
private String test = "test";
private static String static_test= "static_test";
private String getName(String args){
    return args + "name";
}
public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException, ClassNotFoundException, InstantiationException, NoSuchMethodException, InvocationTargetException {
    //修改前
    System.out.println("before：" + new ReflectionTest().test);
    System.out.println("before：" + static_test);
    System.out.println("before：" + new ReflectionTest().getName("参数"));

    //修改后
    //查找类名
    Class<?> clazz = Class.forName("ReflectionTest");
    //实例化对象
    Object obj = clazz.newInstance();
    //获取字段
    Field field = clazz.getDeclaredField("test");
    //私有字段需要设置权限为true
    field.setAccessible(true);
    //修改字段值
    field.set(obj,"changeTest");
    System.out.println("after：" + field.get(obj));
    field = clazz.getDeclaredField("static_test");
    field.setAccessible(true);
    //注意，这里修改的是静态字段，不需要实例化对象
    field.set(clazz,"changeStaticTest");
    System.out.println("after：" + field.get(clazz));
    Method method = clazz.getDeclaredMethod("getName", String.class);
    //一样，私有方法需要设置权限
    method.setAccessible(true);
    //反射修改方法参数
    //需要调用实例化对象
    Object result = method.invoke(obj,"changeArgs");
    System.out.println("after：" + result.toString());
}
}

运行结果：
before：test
before：static_test
before：参数name
after：changeTest
after：changeStaticTest
after：changeArgsname