Android文件上传与下载

  文件上传与下载分为客户端与服务器端，这里客户端为Android终端，服务器为web服务器，下面分别建立客户端与服务器端。

 （一）客户端

    客户端界面如下：

上面的界面非常简单，左边一个按钮点击后执行上传动作，左右的图片就是要上传的图片，重点看看上传的代码：

public static String uploadFiles(List<String> files,String RequestURL){String BOUNDARY =  UUID.randomUUID().toString();  //边界标识   随机生成String PREFIX = "--" , LINE_END = "\r\n"; String CONTENT_TYPE = "multipart/form-data";   //内容类型try {URL url = new URL(RequestURL);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setReadTimeout(TIME_OUT);conn.setConnectTimeout(TIME_OUT);conn.setDoInput(true);  //允许输入流conn.setDoOutput(true); //允许输出流conn.setUseCaches(false);  //不允许使用缓存conn.setRequestMethod("POST");  //请求方式conn.setRequestProperty("Charset", CHARSET);  //设置编码conn.setRequestProperty("connection", "keep-alive");   conn.setRequestProperty("Content-Type", CONTENT_TYPE + ";boundary=" + BOUNDARY); conn.addRequestProperty("orderId", "ABC");conn.addRequestProperty("orderIdName", "BBC");if(files!=null){/*** 当文件不为空，把文件包装并且上传*/conn.connect();OutputStream outputSteam = conn.getOutputStream();DataOutputStream dos = new DataOutputStream(outputSteam);StringBuilder paramsStr = new StringBuilder();StringBuilder paramsStr2 = new StringBuilder();//paramsStr2.append("Content-Type: application/x-www-form-urlencoded" + LINE_END);//Map<String, String> params = new HashMap<String, String>();params.put("orderId", "111111222");for (String key : params.keySet()) {paramsStr.append(key);paramsStr.append("=");paramsStr.append(params.get(key));paramsStr.append("&");}paramsStr.deleteCharAt(paramsStr.length() - 1);paramsStr.append(LINE_END);paramsStr2.append("Content-Length: " + paramsStr.length() + LINE_END);for (String file : files) {File uploadFile = new File(file);StringBuffer sb = new StringBuffer();sb.append(PREFIX);sb.append(BOUNDARY);sb.append(LINE_END);/*** 这里重点注意：* name里面的值为服务器端需要key   只有这个key 才可以得到对应的文件* filename是文件的名字，包含后缀名的   比如:abc.png  */sb.append("Content-Disposition: form-data; name=\"img\"; filename=\""+uploadFile.getName()+"\""+LINE_END); sb.append("Content-Type: application/octet-stream; charset="+CHARSET+LINE_END);sb.append(LINE_END);dos.write(sb.toString().getBytes());InputStream is = new FileInputStream(uploadFile);byte[] bytes = new byte[4096];int len = 0;while ((len = is.read(bytes)) != -1) {dos.write(bytes, 0, len);}is.close();dos.write(LINE_END.getBytes());} byte[] end_data = (PREFIX + BOUNDARY + PREFIX + LINE_END).getBytes();dos.write(end_data);dos.flush();/*** 获取响应码  200=成功* 当响应成功，获取响应的流  */int res = conn.getResponseCode();  Log.e(TAG, "response code:"+res);if(res==200){    return SUCCESS;}}} catch (MalformedURLException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return FAILURE;}以上代码注释比较详细，值得注意的是要正确的设置Content-Type属性，由于有可能上传多个文件，所以在第二个for循环中进行处理。以上是客户端，下面来看看服务器端。（二）服务器端protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String orderId = request.getHeader("orderId");Enumeration<String> names = request.getHeaderNames();while (names.hasMoreElements()) {String name = names.nextElement();String value = request.getHeader(name);System.out.println("参数: " + name + " = "+ value);}System.out.println("参数: orderId = " + orderId);      PrintWriter out = response.getWriter();try {List<FileItem> items = this.upload.parseRequest(request);//request.getpaif (items != null && !items.isEmpty()) {for (FileItem fileItem : items) {String filename = fileItem.getName();String filepath = filedir + File.separator + filename;System.out.println("文件保存路径为:" + filepath);File file = new File(filepath);InputStream inputSteam = fileItem.getInputStream();BufferedInputStream fis = new BufferedInputStream(inputSteam);FileOutputStream fos = new FileOutputStream(file);int f;while ((f = fis.read()) != -1) {fos.write(f);}fos.flush();fos.close();fis.close();inputSteam.close();System.out.println("文件：" + filename + "上传成功!");}}System.out.println("上传文件成功!");out.write("上传文件成功!");} catch (FileUploadException e) {e.printStackTrace();out.write("上传文件失败:" + e.getMessage());}}

服务器端的代码更直接，调用parseRequest解析出一个文件列表，然后对这个列表进行遍历，对每个文件对象进行写文件保存到磁盘中，完成！

最后上代码：

客户端：http://download.csdn.net/detail/www586089/8717627

服务器端：http://download.csdn.net/detail/www586089/8717673