在网络上，假设我们超链接地址对应于jpg档,txt档，点击链接，默认浏览器打开这些文件，而不是下载，那么，你如何实现竞争力的默认下载。

1.可通过自己写一个download.jsp来实现

<%@ page contentType="text/html; charset=UTF-8"%>

<%@ page import="java.net.*"%>

<%

	//得到文件名称字和路径

	String filename = request.getParameter("filename");

	String filepath = request.getParameter("filepath");

	String displayfilename = URLEncoder.encode(filename,"UTF-8");

	try {

		response.setContentType("application/x-download");

		response.setHeader("Content-Disposition","attachment;filename=\"" + displayfilename + "\"");

		//HttpServletContext httpServletContext = (HttpServletContext)application;

	    RequestDispatcher dis = application.getRequestDispatcher(filepath + filename);

	    //application.getRequestDispatcher(url)这里的url仅仅能是相对路径,如/upload/1.jpg

	    if (dis != null) {

	        dis.forward(request,response);

	    }

	    response.flushBuffer();

	} catch (Exception e) {

		e.printStackTrace();

	    System.out.println("下载取消：" + filepath + filename);

	}

	out.clear();

    out = pageContext.pushBody();

%>

当我们要链接图片（或其它浏览器默认打开的格式，这里以图片为例）时。把相应的文件名称和地址传入download.jsp的filename和filepath參数里。详细写法例如以下

<a class="blue-line-a" href=" /PackTool/download.jsp?

filename=WinGUI.exe&filepath=/other/WinGUI.exe">/other/WinGUI.exe</a>

通过这样方式，我们就能实现文件的默认下载了，而不是浏览器的默认打开。

2.通过文件输出流方式（推荐）：

<%@ page language="java" contentType="application/x-msdownload"    pageEncoding="UTF-8"%>

<%@ page import="java.net.*"%>

<%@ page import="java.io.*"%>

<%@ page import="com.hikvision.modules.guide.util.*"%>

<%

      //关于文件下载时採用文件流输出的方式处理：

      //加上response.reset()，而且全部的％>后面不要换行。包含最后一个；

	  String filename = request.getParameter("filename");

	  String filepath = request.getParameter("filepath");

      response.reset();//能够加也能够不加

      response.setContentType("application/x-download");

      //"想办法找到要提供下载的文件的物理路径＋文件名称";D:/PackTools/shareFolder

      String filedownload = GetSharePathXml.getShareFolderPath() + filename;

      //"给用户提供的下载文件名称"

      String filedisplay = filename;

      filedisplay = URLEncoder.encode(filedisplay,"UTF-8");

      response.addHeader("Content-Disposition","attachment;filename=" + filedisplay);

      OutputStream outp = null;

      FileInputStream in = null;

      try

      {

          outp = response.getOutputStream();

          in = new FileInputStream(filedownload); 

          byte[] b = new byte[1024];

          int i = 0;

          while((i = in.read(b)) > 0)

          {

              outp.write(b, 0, i);

          }

          outp.flush();

      }

      catch(Exception e)

      {

          System.out.println("Error!");

          e.printStackTrace();

      }

      finally

      {

          if(in != null)

          {

              in.close();

              in = null;

          }

          if(outp != null)

          {

              outp.close();

              out.clear();

              outp = null;

          }

      }

%>