在struts2中使用filter来配置servlet处理业务。。。。

在一个struts2项目中，如果同时用到了servlet和struts2的框架，运行项目时可能无法正常使用servlet，原因是在配置struts2的核心控制器时如下配置所致

<filter>
  <filter-name>struts2</filter-name>
  <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
 </filter>

 <filter-mapping>
  <filter-name>struts2</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>

此时要想请求不经过该FilterDispatcher过滤器而直接响应servlet，可以通过自定义一个过滤器，将servlet过滤，使struts2的核心控制器对servlet不起作用。注意：在xml文件中定义的servlet过滤器要写在struts2核心控制器前面，否则还是不能使用。举例来说，定义的过滤器文件是ReDispatcherFilter.java，只需按照该文件中注释内容做以下配置，即可

<filter>
   <filter-name>redisp</filter-name>
   <filter-class>filters.ReDispatcherFilter</filter-class>
   <init-param>
    <param-name>includeServlets</param-name>
    <param-value>attachmentUpload.do,aa.do</param-value>
   </init-param>
 </filter>
 <filter-mapping>
   <filter-name>redisp</filter-name>
   <url-pattern>/*</url-pattern>
 </filter-mapping>
   <servlet>
        <servlet-name>attachmentUpload</servlet-name>
        <servlet-class>com.yan.AttachmentUploadServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>attachmentUpload</servlet-name>
        <url-pattern>/attachmentUpload.do</url-pattern>
    </servlet-mapping>

在filters包下定义ReDispatcherFilter类，如下：

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
public class ReDispatcherFilter implements Filter {

public void destroy() {
   // TODO Auto-generated method stub

}

public void doFilter(ServletRequest req, ServletResponse resp,
    FilterChain chain) throws IOException, ServletException
{
 
   System.out.println(" filter  beginning...........");
 HttpServletRequest request = (HttpServletRequest)req;
   String target = request.getRequestURI();
   target = target.lastIndexOf("?")>0  
      ?target.substring(target.lastIndexOf("/")+1,target.lastIndexOf("?")-target.lastIndexOf("/"))
      :target.substring(target.lastIndexOf("/")+1);
 
   System.out.println(target);
   for(int i=0;i<this.includes.size();i++)
    System.out.println(this.includes.get(i));
   if(this.includes.contains(target))
   {
    System.out.println("includes.contains(target) is true");
    RequestDispatcher rdsp = request.getRequestDispatcher(target);
  
    System.out.println("go..............."+rdsp);
    rdsp.forward(req, resp);
   }
   else
    chain.doFilter(req, resp);
}
private ArrayList<String> includes = new ArrayList<String>();

public void init(FilterConfig config) throws ServletException {
 
   this.includes.addAll( Arrays.asList(config.getInitParameter("includeServlets").split(",")));

}

}

http://hi.baidu.com/xsl2007/blog/item/4eb796cf94e35f0992457e11.html