webwork的interceptor來實現ajax功能(buffalo)

已經很久沒有來bolg了，現在有空，就把最近寫的一個webwork的攔截器放上來給大家參考，如果有bug或有更好的實現辦法，可以email給我。

下面是interceptor的實現代碼：

 1 package interceptor;
 2 
 3 import java.io.IOException;
 4 
 5 import org.apache.log4j.Logger;
 6 
 7 import com.caucho.burlap.io.BurlapInput;
 8 import com.caucho.burlap.io.BurlapOutput;
 9 import com.caucho.burlap.server.BurlapSkeleton;
10 import com.opensymphony.webwork.ServletActionContext;
11 import com.opensymphony.xwork.ActionInvocation;
12 import com.opensymphony.xwork.interceptor.Interceptor;
13 
14 public class BurlapInterceptor implements Interceptor {
15     private static Logger logger = Logger.getLogger(BurlapInterceptor.class);
16     public void destroy() {
17         // TODO Auto-generated method stub
18 
19     }
20 
21     public void init() {
22         // TODO Auto-generated method stub
23 
24     }
25 
26     public String intercept(ActionInvocation invocation) throws Exception {
27         BurlapInput in = new BurlapInput(ServletActionContext.getRequest()
28                 .getInputStream());
29 
30         BurlapOutput out = new BurlapOutput(ServletActionContext.getResponse().getOutputStream()) {
31             public void startReply() throws IOException {
32                 print("<?xml version=\"1.0\" encoding=\"utf-8\"?><burlap:reply xmlns:burlap=\"http://www.buffalo.net/burlap/\">");
33             }
34         };
35 
36         BurlapSkeleton _skeleton = new BurlapSkeleton(invocation.getAction());
37 
38         try {
39             _skeleton.invoke(in, out);
40         }
41         catch (Throwable e) {
42             logger.error("Could not invoke burlap", e);
43         }
44         return null;
45     }
46 
47 }
48 

然後在xwork.xml中定義：1         <interceptors>
2               <interceptor name="burlap" class="interceptor.BurlapInterceptor"/>        
3          </interceptors>
4 

最好就可以使用這個攔截器定義自己的bean了，例如：1    <action name="classtree" class="classTreeAction" method="getClassList">
2        <interceptor-ref name="burlap" />
3    </action>

在頁面上就可以用如下javascript代碼去調用這個action：
   var bfl = new Buffalo("classtree.page");
   bfl.remoteCall("getClassList",[acadyear,semester],function(reply){...});

如果你不瞭解buffalo，可以去他的網站看看：http://www.amowa.net/buffalo/