servlet 下载

package com.zhangyun;
import java.io.FileInputStream;  
import java.io.IOException;  
import java.net.URLEncoder;  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;  

public class DownFile extends HttpServlet
{  
      public void doGet(HttpServletRequest request, HttpServletResponse response)  
                    throws ServletException, IOException {  
             //1.获取要下载的资源  
             String path = this.getServletContext().getRealPath("/download/a.avi");  
             String filename = path.substring(path.lastIndexOf("\\")+1);  
             //System.out.println(filename);  
             //2.通知浏览器以下载方式打开发送过来的数据  
             //response.setHeader("content-disposition","attachment;filename="+filename);  
             //如果文件名是中文，要经过URL编码  
             response.setHeader("content-disposition","attachment;filename="+URLEncoder.encode(filename,"UTF-8"));  
             //如果文件名是中文，要经过URL编码  
             //3.读取资源内容  
             FileInputStream fis = new FileInputStream(path);  
             byte[]buffer = new byte[1024];  
             int len = 0;  
             while((len=fis.read(buffer))>0){  
                    response.getOutputStream().write(buffer,0,len);  
             }  
             fis.close();  
      }  
      public void doPost(HttpServletRequest request, HttpServletResponse response)  
                    throws ServletException, IOException {  
             doGet(request,response);  
      }  
}