下载文件

/** 

* 下载文件

* @param mapping

* @param form

* @param request

* @param response

* @return ActionForward

*/

@SuppressWarnings("deprecation")

public ActionForward doDownload(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) {

FileForm fileForm = (FileForm) form;

OutputStream toClient = null;

try {

//测试--设置为固定路径

String path = request.getRealPath("/") + "upload//" + fileForm.getFileName();

File file = new File(path);

String filename = file.getName();

// 取得文件的扩展名

String ext = filename.substring(filename.lastIndexOf(".") + 1)

.toUpperCase();

InputStream fis = null;

try{

fis = new BufferedInputStream(new FileInputStream(path));

}catch(FileNotFoundException e){

e.printStackTrace();

System.out.println("系统没有找到指定文件");

}

if(fis==null){

response.getWriter().print("<script>alert('系统没有找到指定文件!');history.go(-1);</script>");

return null;

}

byte[] buffer = new byte[fis.available()];

fis.read(buffer);

fis.close();

response.reset();

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

+ new String(filename.getBytes()));

response.addHeader("Content-Length", "" + file.length()); // 设置返回的文件类型

toClient = new BufferedOutputStream(response

.getOutputStream()); // 得到向客户端输出二进制数据的对象

// 根据扩展名声称客户端浏览器mime类型

if (ext.equals("DOC"))

response.setContentType("application/msword");

else

response.setContentType("application/octet-stream"); // 设置返回的文件类型

try{

if(toClient != null){

toClient.write(buffer); // 输出数据

toClient.flush();

}

}catch(Exception e){

e.printStackTrace();

System.out.println("用户取消下载文件...");

}

} catch (IOException ex) {

ex.printStackTrace();

} finally{

try {

if(toClient!=null){

toClient.close();

}

} catch (IOException e) {

e.printStackTrace();

}

}

return null;

}