Dynamic proxy (Dynamic proxy Mode)

Dynamic proxy (runtime behavior) mainly includes a proxy class and an invocationhandler interface.

Dynamic proxy role:

1. Abstract topic role

2. Real topic role (implemented the abstract topic Interface)

3. Dynamic proxy topic role (implements the invocationhandler interface and the invoke () method)

Proxy needs to call the newproxyinstance Method

 

Code Demonstration:

 

1. Abstract topic role subjectdemo. Java

 

Package com. dynamicproxy; </P> <p> Public interface subjectdemo <br/>{< br/> Public void request (); <br/>}< br/>

 

2. Real topic role realsubjectdemo. Java

 

Package COM. dynamicproxy; </P> <p> public class realsubjectdemo implements subjectdemo <br/>{< br/> Public void request () <br/>{< br/> system. out. println ("implemented a request"); <br/>}< br/>}

 

3. Dynamic proxy topic role dynamicproxysubjectdemo. Java

 

Package COM. dynamicproxy; </P> <p> Import Java. lang. reflect. invocationhandler; <br/> Import Java. lang. reflect. method; </P> <p> public class dynamicproxysubjectdemo implements invocationhandler <br/>{< br/> private object sub; </P> <p> Public dynamicproxysubjectdemo (Object OBJ) <br/>{< br/> This. sub = OBJ; <br/>}</P> <p> Public object invoke (Object proxy, method, object [] ARGs) throws throwable <br/>{< br/> system. out. println ("before" + method); </P> <p> method. invoke (sub, argS); // real call method operation </P> <p> system. out. println ("after" + method); </P> <p> return NULL; </P> <p >}</P> <p>}

4. Client. Java

 

Package COM. dynamicproxy; </P> <p> Import Java. lang. reflect. invocationhandler; <br/> Import Java. lang. reflect. proxy; </P> <p> public class client <br/> {<br/> Public static void main (string [] ARGs) <br/>{< br/> realsubjectdemo RSD = new realsubjectdemo (); </P> <p> invocationhandler handler = new dynamicproxysubjectdemo (RSD ); </P> <p> class <?> Classtype = handler. getclass (); </P> <p> // classtype. getclassloader (): Class Loader of the dynamic proxy class <br/> // RSD. getclass (). list of interfaces to be implemented by the getinterfaces () proxy class <br/> // call handler for Handler to assign a method call <br/> subjectdemo SD = (subjectdemo) proxy. newproxyinstance (classtype. getclassloader (), RSD. getclass (). getinterfaces (), Handler); </P> <p> // This line of code is executed and transferred to invocationhandler handler = new dynamicproxysubjectdemo (RSD) <br/> // execute the invoke method <br/> SD. request (); <br/>}< br/>