java 反射调用另一个类中的方法

class A:

 

import java.lang.reflect.Method;

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("before test Dex");
        HelloWorld hw = new HelloWorld();
        hw.test();
        System.out.println("after test Dex");
    }

    public void test() {
        try {
            Class<?> cls = null;
            cls = Class.forName("Dex");
            Object obj = cls.newInstance();
            Method setFunc = cls.getDeclaredMethod("testDex");
            setFunc.invoke(obj);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

 

Class B:

public class Dex {
    void testDex() {
        System.out.println("Dex123");
    }
}