Java反射二 动态调用类的方法

package fanshe;

public class Person {
private int age;
private String name;

private String info(){
return "My name is "+ name +", I'm "+age+" years old.";
}

private void sayHellow(String word){
System.out.println(word);
}
}

package fanshe;

import java.lang.reflect.Field;
import java.lang.reflect.Method;

public class Mymain {

public static void main(String[] args) throws Exception{
Mymain.invokeMethod("fanshe.Person", "sayHellow", "hellow");

private static void invokeMethod (String className, String methodName, String value) throws Exception{
Class clazz = Class.forName(className);
Method mtd = clazz.getDeclaredMethod(methodName, String.class);
mtd.setAccessible(true);
mtd.invoke(clazz.newInstance(), value);
}
}