通过反射API构造对象，并使用反射调用方式访问对象的public/private方法和字段。
 
package lavasoft.test; 

/** 
* 测试的业务类 
* 
* @author leizhimin 2010-5-6 20:16:10 
*/ 
public class MyService { 
        private String msg; 

        public MyService() { 
                System.out.println("log: 无参构造方法lavasoft.test.MyService.MyService()被调用过了！"); 
        } 

        public MyService(String msg) { 
                System.out.println("log: 有参构造方法lavasoft.test.MyService.MyService()被调用过了！"); 
                this.msg = msg; 
        } 

        public String doSomething(String person, String something) { 
                System.out.println("log: 业务方法lavasoft.test.MyService.doSomething()被调用过了！"); 
                return person + " is doing " + something + "!    " + 
                                "附加消息：" + msg; 
        } 

        public String getMsg() { 
                System.out.println("log: lavasoft.test.MyService.getMsg()被调用过了！"); 
                return msg; 
        } 

        public void setMsg(String msg) { 
                System.out.println("log: lavasoft.test.MyService.setMsg()被调用过了！"); 
                this.msg = msg; 
        } 

        private String doPrivate() { 
                System.out.println("log: 私有方法lavasoft.test.MyService.doPrivate()被调用过了！"); 
                return "私有方法doPrivate()被调用了!"; 
        } 
}
 
package lavasoft.test; 

import java.lang.reflect.Constructor; 
import java.lang.reflect.InvocationTargetException; 
import java.lang.reflect.*; 

/** 
* Java反射深度测试 
* 
* @author leizhimin 2010-5-6 20:26:49 
*/ 
public class TestReflect { 
        public static void main(String[] args) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException, InstantiationException, NoSuchFieldException { 
                //通过反射方式创建对象 
                Class clazz = MyService.class; 
                MyService sv = (MyService)clazz.getConstructor().newInstance(); 
                sv.setMsg("通过Class方式创建一个对象，并调用对象上的方法！"); 

                //通过反射方式调用对象的public方法 
                Method m_setMsg =    clazz.getMethod("setMsg",String.class); 
                m_setMsg.invoke(sv,"通过反射调用了sv对象上的一个方法！"); 
                Method m_do    = clazz.getMethod("doSomething",String.class ,String.class); 
                String re = (String)m_do.invoke(sv,"张三" ,"吃饭"); 
                System.out.println(re); 

                //通过反射方式调用对象的private方法 
                Method m_doPrivate = clazz.getDeclaredMethod("doPrivate"); 
                m_doPrivate.setAccessible(true); 
                m_doPrivate.invoke(sv); 

                //通过反射方式访问对象private字段 
                Field f_msg = clazz.getDeclaredField("msg"); 
                f_msg.setAccessible(true); 
                f_msg.set(sv,"hahahahahahahaha"); 
                System.out.println(sv.getMsg()); 
        } 
}
 
log: 无参构造方法lavasoft.test.MyService.MyService()被调用过了！ 
log: lavasoft.test.MyService.setMsg()被调用过了！ 
log: lavasoft.test.MyService.setMsg()被调用过了！ 
log: 业务方法lavasoft.test.MyService.doSomething()被调用过了！ 
张三 is doing 吃饭!    附加消息：通过反射调用了sv对象上的一个方法！ 
log: 私有方法lavasoft.test.MyService.doPrivate()被调用过了！ 
log: lavasoft.test.MyService.getMsg()被调用过了！ 
hahahahahahahaha 

Process finished with exit code 0