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4.ÄÄЩµØ·½ÐèÒª¶¯Ì¬´úÀí?

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1.interface InvocationHandler
Object invoke(Object proxy, Method method, Object[] args)
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2.class Proxy
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Class<?> getProxyClass(ClassLoader loader, Class<?>[] interface)
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Object newProxyInstance(ClassLoader loader, Class<?>[] interfaces, InvocationHandler h)
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Java´úÂë  

1. public interface Hello {

2.  

3.  void sayHello(String to);

4.  

5.  void print(String p);

6.  

7. }  

ËüµÄÕæʵʵÏÖÀà:

Java´úÂë  

1. public class HelloImpl implements Hello {

2.  

3.  public void sayHello(String to) { 

4.  System.out.println("Say hello to " + to);

5.  }

6.  

7.  public void print(String s) {

8.  System.out.println("print " + s);

9.  }

10.  

11. }

ÔÚÕâÀïÉú³ÉÓë´úÀíÀàÏà¹ØÁªµÄInvocationHandler¶ÔÏó

Java´úÂë  

1. public class LogHandler implements InvocationHandler {

2.  

3.  private Object dele;

4.  

5.  public LogHandler(Object obj) {

6.  this.dele=obj; }

7. public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

8.  doBefore();

9.  //ÔÚÕâÀïÍêÈ«¿ÉÒÔ°ÑÏÂÃæÕâ¾ä×¢Ê͵ô£¬¶ø×öһЩÆäËüµÄÊÂÇé  

10.  Object result = method.invoke(dele, args);

11.  after();

12.  return result;

13.  }

14.  

15.  private void doBefore() {

16.  System.out.println("before....");

17.  }

18.  

19.  private void after() {

20.  System.out.println("after....");

21.  }

22. }

×îºóÊDzâÊÔÀà:

Java´úÂë  

1. public class ProxyTest {

2.  

3.  public static void main(String[] args) {

4.  HelloImpl impl = new HelloImpl();

5.  LogHandler handler = new LogHandler(impl);

6.  //ÕâÀï°ÑhandlerÓëimplÐÂÉú³ÉµÄ´úÀíÀàÏà¹ØÁª  

7.  Hello hello = (Hello) Proxy.newProxyInstance(impl.getClass().getClassLoader(), impl.getClass().getInterfaces(), handler);

8.  

9.  //ÕâÀïÎÞÂÛ·ÃÎÊÄĸö·½·¨£¬¶¼ÊÇ»á°ÑÇëÇóת·¢µ½handler.invoke

10.  hello.print("All the test");

11.  hello.sayHello("Denny");

12.  }

13.  

14. }

ÕâÀïÊÇÊä³ö½á¹û:

Java´úÂë  

1. before...

2. print : All the test

3. after....

4. before....

5. Say hello to Denny

6. after....

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