Java下载文件格式

    public HttpServletResponse download(String path, HttpServletResponse response) {
    try {
    // path是指欲下载的文件的路径。
    File file = new File(path);
    // 取得文件名。
    String filename = file.getName();
    // 取得文件的后缀名。
    String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();
    // 以流的形式下载文件。
    InputStream fis = new BufferedInputStream(new FileInputStream(path));
    byte[] buffer = new byte[fis.available()];
    fis.read(buffer);
    fis.close();
    // 清空response
    response.reset();
    // 设置response的Header
    response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));
    response.addHeader("Content-Length", "" + file.length());
    OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
    response.setContentType("application/octet-stream");
    toClient.write(buffer);
    toClient.flush();
    toClient.close();
    } catch (IOException ex) {
    ex.printStackTrace();
    }
    return response;
    }
    public void downloadLocal(HttpServletResponse response) throws FileNotFoundException {
    // 下载本地文件
    String fileName = "Operator.doc".toString(); // 文件的默认保存名
    // 读到流中
    InputStream inStream = new FileInputStream("c:/Operator.doc");// 文件的存放路径
    // 设置输出的格式
    response.reset();
    response.setContentType("bin");
    response.addHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
    // 循环取出流中的数据
    byte[] b = new byte[100];
    int len;
    try {
    while ((len = inStream.read(b)) > 0)
    response.getOutputStream().write(b, 0, len);
    inStream.close();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    public void downloadNet(HttpServletResponse response) throws MalformedURLException {
    // 下载网络文件
    int bytesum = 0;
    int byteread = 0;
    URL url = new URL("windine.blogdriver.com/logo.gif");
    try {
    URLConnection conn = url.openConnection();
    InputStream inStream = conn.getInputStream();
    FileOutputStream fs = new FileOutputStream("c:/abc.gif");
    byte[] buffer = new byte[1204];
    int length;
    while ((byteread = inStream.read(buffer)) != -1) {
    bytesum += byteread;
    System.out.println(bytesum);
    fs.write(buffer, 0, byteread);
    }
    } catch (FileNotFoundException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    //支持在线打开文件的一种方式
    public void downLoad(String filePath, HttpServletResponse response, boolean isOnLine) throws Exception {
    File f = new File(filePath);
    if (!f.exists()) {
    response.sendError(404, "File not found!");
    return;
    }
    BufferedInputStream br = new BufferedInputStream(new FileInputStream(f));
    byte[] buf = new byte[1024];
    int len = 0;
    response.reset(); // 非常重要
    if (isOnLine) { // 在线打开方式
    URL u = new URL("file:///" + filePath);
    response.setContentType(u.openConnection().getContentType());
    response.setHeader("Content-Disposition", "inline; filename=" + f.getName());
    // 文件名应该编码成UTF-8
    } else { // 纯下载方式
    response.setContentType("application/x-msdownload");
    response.setHeader("Content-Disposition", "attachment; filename=" + f.getName());
    }
    OutputStream out = response.getOutputStream();
    while ((len = br.read(buf)) > 0)
    out.write(buf, 0, len);
    br.close();
    out.close();
    }

如果生成一个Excel并下载

//导出
    @RequestMapping("/outputExcelByActivity.ca")                      
    public void outputExcelByActivity(HttpServletRequest request,HttpServletResponse response,
                                      @RequestParam("ids") String ids) throws Exception{
        response.addHeader("Content-Disposition", "attachment;filename=" + "outputExcel.xls");
        response.setContentType("application/octet-stream");
        String[] nums = ids.split(",");
        Long[] ids1 = new Long[nums.length];
        for (int i = 0; i < nums.length; ++i) {
            ids1[i] = Long.valueOf(nums[i]);
        }
        List<MerchantOrder> list = activityManager.getOutputExcelOrder(ids1);
        OrderExcelHelper.export(response.getOutputStream(),list);
    }