下载文件

public void download(HttpServletRequest request, HttpServletResponse response) throws IOException{
        
        //String filePath = "src/main/webapp/apk/android/NCB.apk";
        String filePath=request.getSession().getServletContext().getRealPath("/apk/android/NCB.apk");
        File file = new File(filePath);
         
        /* 如果文件存在 */
        if (file.exists()) {
            String fileName = URLEncoder.encode(file.getName(), enc);
            response.reset();

            ServletContext servletContext=request.getServletContext();

            response.setContentType(servletContext.getMimeType(fileName));  
        
            response.addHeader("Content-Disposition", "attachment; filename=" + fileName);
            int fileLength = (int) file.length();
            response.setContentLength(fileLength);
            /* 如果文件长度大于0 */
            if (fileLength > 0) {
                /* 创建输入流 */
                InputStream inStream = null;
                ServletOutputStream outStream = null;
                try {
                    inStream = new FileInputStream(file);
                    byte[] buf = new byte[4096];
                    /* 创建输出流 */
                    outStream = response.getOutputStream();
                    int readLength;
                    while (((readLength = inStream.read(buf)) != -1)) {
                        outStream.write(buf, 0, readLength);
                    }
                } finally {
                    inStream.close();
                    outStream.flush();
                    outStream.close();
                }
            }
        }
    }

 public void downloadTemplate(HttpServletRequest request, HttpServletResponse response)
 6             throws UnsupportedEncodingException {
 7         String path = request.getSession().getServletContext().getRealPath("");
 8         String filename = "模板文件.xls";
 9         File file = new File(path +  "\\file\\templagte\\" + filename);
10         String userAgent = request.getHeader("User-Agent");
11         byte[] bytes = userAgent.contains("MSIE") ? filename.getBytes() : filename.getBytes("UTF-8"); // fileName.getBytes("UTF-8")处理safari的乱码问题
12         String fileName = new String(bytes, "ISO-8859-1"); 
13         // 设置输出的格式
14         response.setContentType("multipart/form-data");
15         response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8"));
16         
17         InputStream inStream = null;
18         try {
19             inStream = new FileInputStream(file);
20             IOUtils.copy(inStream, response.getOutputStream());//使用commons-io组件进行文件流的处理
21         } catch (IOException e) {
22             e.printStackTrace();
23         }finally{
24             IOUtils.closeQuietly(inStream);
25         }