java

   private String uploadFile(String uploadUrl, String filename) {
        String end = "\r\n";
        String twoHyphens = "--";
        String boundary = "******";
        try {
            URL url = new URL(uploadUrl);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            // 设置每次传输的流大小，可以有效防止手机因为内存不足崩溃
            // 此方法用于在预先不知道内容长度时启用没有进行内部缓冲的 HTTP 请求正文的流。
            httpURLConnection.setChunkedStreamingMode(128 * 102400);// 128K
            // 允许输入输出流
            httpURLConnection.setDoInput(true);
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setUseCaches(false);
            // 使用POST方法
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setRequestProperty("Connection", "Keep-Alive");
            httpURLConnection.setRequestProperty("Charset", "UTF-8");
            httpURLConnection.setRequestProperty("Content-Type",
                    "multipart/form-data;boundary=" + boundary);
            DataOutputStream dos = new DataOutputStream(httpURLConnection.getOutputStream());
            dos.writeBytes(twoHyphens + boundary + end);
            dos.writeBytes("Content-Disposition: form-data; name=\"file\"; filename=\"" + filename.substring(filename.lastIndexOf("/") + 1)
                    + "\""
                    + end);
            dos.writeBytes(end);

            FileInputStream fis = new FileInputStream(filename);
            byte[] buffer = new byte[81920000]; // 8k
            int count = 0;
            // 读取文件
            while ((count = fis.read(buffer)) != -1) {
                dos.write(buffer, 0, count);
            }
            fis.close();

            dos.writeBytes(end);
            dos.writeBytes(twoHyphens + boundary + twoHyphens + end);
            dos.flush();

            InputStream is = httpURLConnection.getInputStream();
            InputStreamReader isr = new InputStreamReader(is, "utf-8");
            BufferedReader br = new BufferedReader(isr);
            String result = br.readLine();


            dos.close();
            is.close();
            return result;
        } catch (Exception e)  {
            e.printStackTrace();
            return e.getMessage();
        }
    }