Java反射深度測試

通過反射API構造對象，并使用反射調用方式通路對象的public/private方法和字段。

package lavasoft.test; 

/** 

* 測試的業務類 

* 

* @author leizhimin 2010-5-6 20:16:10 

*/ 

public class MyService { 

        private String msg; 

        public MyService() { 

                System.out.println("log: 無參構造方法lavasoft.test.MyService.MyService()被調用過了！"); 

        } 

        public MyService(String msg) { 

                System.out.println("log: 有參構造方法lavasoft.test.MyService.MyService()被調用過了！"); 

                this.msg = msg; 

        public String doSomething(String person, String something) { 

                System.out.println("log: 業務方法lavasoft.test.MyService.doSomething()被調用過了！"); 

                return person + " is doing " + something + "!    " + 

                                "附加消息：" + msg; 

        public String getMsg() { 

                System.out.println("log: lavasoft.test.MyService.getMsg()被調用過了！"); 

                return msg; 

        public void setMsg(String msg) { 

                System.out.println("log: lavasoft.test.MyService.setMsg()被調用過了！"); 

        private String doPrivate() { 

                System.out.println("log: 私有方法lavasoft.test.MyService.doPrivate()被調用過了！"); 

                return "私有方法doPrivate()被調用了!"; 

}

import java.lang.reflect.Constructor; 

import java.lang.reflect.InvocationTargetException; 

import java.lang.reflect.*; 

* Java反射深度測試 

* @author leizhimin 2010-5-6 20:26:49 

public class TestReflect { 

        public static void main(String[] args) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException, InstantiationException, NoSuchFieldException { 

                //通過反射方式建立對象 

                Class clazz = MyService.class; 

                MyService sv = (MyService)clazz.getConstructor().newInstance(); 

                sv.setMsg("通過Class方式建立一個對象，并調用對象上的方法！"); 

                //通過反射方式調用對象的public方法 

                Method m_setMsg =    clazz.getMethod("setMsg",String.class); 

                m_setMsg.invoke(sv,"通過反射調用了sv對象上的一個方法！"); 

                Method m_do    = clazz.getMethod("doSomething",String.class ,String.class); 

                String re = (String)m_do.invoke(sv,"張三" ,"吃飯"); 

                System.out.println(re); 

                //通過反射方式調用對象的private方法 

                Method m_doPrivate = clazz.getDeclaredMethod("doPrivate"); 

                m_doPrivate.setAccessible(true); 

                m_doPrivate.invoke(sv); 

                //通過反射方式通路對象private字段 

                Field f_msg = clazz.getDeclaredField("msg"); 

                f_msg.setAccessible(true); 

                f_msg.set(sv,"hahahahahahahaha"); 

                System.out.println(sv.getMsg()); 

log: 無參構造方法lavasoft.test.MyService.MyService()被調用過了！ 

log: lavasoft.test.MyService.setMsg()被調用過了！ 

log: 業務方法lavasoft.test.MyService.doSomething()被調用過了！ 

張三 is doing 吃飯!    附加消息：通過反射調用了sv對象上的一個方法！ 

log: 私有方法lavasoft.test.MyService.doPrivate()被調用過了！ 

log: lavasoft.test.MyService.getMsg()被調用過了！ 

hahahahahahahaha 

Process finished with exit code 0

本文轉自 leizhimin 51CTO部落格，原文連結：http://blog.51cto.com/lavasoft/311484，如需轉載請自行聯系原作者