Java反射深度测试


  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

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