java动态代理-InvocationHandler Proxy

<!-- /* Font Definitions */ @font-face{font-family:宋体;panose-1:2 1 6 0 3 1 1 1 1 1;mso-font-alt:SimSun;mso-font-charset:134;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:3 135135232 16 0 262145 0;}@font-face{font-family:"/@宋体";panose-1:2 1 6 0 3 1 1 1 1 1;mso-font-charset:134;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:3 135135232 16 0 262145 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-parent:"";margin:0cm;margin-bottom:.0001pt;text-align:justify;text-justify:inter-ideograph;mso-pagination:none;font-size:10.5pt;mso-bidi-font-size:12.0pt;font-family:"Times New Roman";mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;} /* Page Definitions */ @page{mso-page-border-surround-header:no;mso-page-border-surround-footer:no;}@page Section1{size:612.0pt 792.0pt;margin:72.0pt 90.0pt 72.0pt 90.0pt;mso-header-margin:36.0pt;mso-footer-margin:36.0pt;mso-paper-source:0;}div.Section1{page:Section1;} /* List Definitions */ @list l0{mso-list-id:256713394;mso-list-template-ids:-1699456634;}@list l1{mso-list-id:292448747;mso-list-template-ids:1567683388;}@list l2{mso-list-id:1199665814;mso-list-template-ids:1173917332;}@list l3{mso-list-id:1333723713;mso-list-template-ids:1064840542;}@list l4{mso-list-id:2066417278;mso-list-template-ids:-1552372328;}ol{margin-bottom:0cm;}ul{margin-bottom:0cm;}-->

实现动态代理：

真实的接口:

Java代码

1. public interface Hello {  
2.   
3.     void sayHello(String to);  
4.     
5.     void print(String p);   
6.    
7. }  

public interface Hello {

 

    void sayHello(String to);

 

    void print(String p);

 

}

它的真实实现类:

Java代码

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. }  

public class HelloImplimplements Hello {

   

    public void sayHello(String to) {

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

    }

   

    public void print(String s) {

        System.out.println("print : "+ s);

    }

   

}

在这里生成与代理类相关联的InvocationHandler对象

Java代码

1. public class LogHandler implements InvocationHandler {  
2.       
3.     private Object dele;  
4.       
5.     public LogHandler(Object obj) {  
6.         this.dele = obj;  
7.     }  
8.       
9.     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {  
10.         doBefore();  
11.         //在这里完全可以把下面这句注释掉，而做一些其它的事情  
12.         Object result = method.invoke(dele, args);  
13.         after();  
14.         return result;  
15.     }  
16.       
17.     private void doBefore() {  
18.         System.out.println("before....");  
19.     }  
20.       
21.     private void after() {  
22.         System.out.println("after....");  
23.     }  
24. }  

public class LogHandlerimplements InvocationHandler {

   

    private Object dele;

   

    public LogHandler(Object obj) {

        this.dele = obj;

    }

   

    public Object invoke(Object proxy, Methodmethod, Object[] args) throws Throwable {

        doBefore();

        //在这里完全可以把下面这句注释掉，而做一些其它的事情

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

        after();

        return result;

    }

   

    private void doBefore() {

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

    }

   

    private void after() {

       System.out.println("after....");

    }

}

最后是测试类:

Java代码

1. public class ProxyTest {  
2.   
3.     public static void main(String[] args) {  
4.         HelloImpl impl = new HelloImpl();  
5.         LogHandler handler = new LogHandler(impl);  
6.         //这里把handler与impl新生成的代理类相关联  
7.         Hello hello = (Hello) Proxy.newProxyInstance(impl.getClass().getClassLoader(), impl.getClass().getInterfaces(), handler);  
8.           
9.         //这里无论访问哪个方法，都是会把请求转发到handler.invoke  
10.         hello.print("All the test");  
11.         hello.sayHello("Denny");  
12.     }  
13.   
14. }  

public class ProxyTest {

 

    public static void main(String[] args) {

        HelloImpl impl = new HelloImpl();

        LogHandler handler = newLogHandler(impl);

        //这里把handler与impl新生成的代理类相关联

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

       

        //这里无论访问哪个方法，都是会把请求转发到handler.invoke

        hello.print("All the test");

        hello.sayHello("Denny");

    }

 

}

这里是输出结果:

Java代码

1. before....  
2. print : All the test  
3. after....  
4. before....  
5. Say hello to Denny  
6. after....  

before....

print : All the test

after....

before....

Say hello to Denny

after....