下载 

import java.io.File;  import java.io.FileInputStream;  import java.io.IOException;  import java.net.URLEncoder;    import javax.servlet.ServletException;  import javax.servlet.ServletOutputStream;  import javax.servlet.http.HttpServlet;  import javax.servlet.http.HttpServletRequest;  import javax.servlet.http.HttpServletResponse;    public class DownLoadServlet extends HttpServlet {              public DownLoadServlet() {          super();      }          public void destroy() {          super.destroy(); // Just puts "destroy" string in log          // Put your code here      }          public void doGet(HttpServletRequest request, HttpServletResponse response)              throws ServletException, IOException {          doPost(request,response);      }              public void doPost(HttpServletRequest request, HttpServletResponse response)              throws ServletException, IOException {          //处理请求          //读取要下载的文件          File f = new File("E:/好久不见.mp3");          if(f.exists()){              FileInputStream  fis = new FileInputStream(f);              String filename=URLEncoder.encode(f.getName(),"utf-8"); //解决中文文件名下载后乱码的问题              byte[] b = new byte[fis.available()];              fis.read(b);              response.setCharacterEncoding("utf-8");              response.setHeader("Content-Disposition","attachment; filename="+filename+"");              //获取响应报文输出流对象              ServletOutputStream  out =response.getOutputStream();              //输出              out.write(b);              out.flush();              out.close();          }                   }        /**      * Initialization of the servlet. 
      *      * @throws ServletException if an error occurs      */      public void init() throws ServletException {          // Put your code here      }    }