HttpFileUploader.java

    private static final String HTTP_END = "\r\n";
    private static final String HTTP_START = "--";
    private static final String HTTP_BOUNDARY = "*******";


    private boolean uploadFileToServer(File file) {
        if (file == null || !file.exists()) {
            LogUtil.d(TAG, "file not exists, ignore upload.");
            return true;
        }

        try {
            LogUtil.d(TAG, "begin upload file to server.");
            final URL url = new URL("url");
            final String name = file.getName();
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setConnectTimeout(30000);
            connection.setReadTimeout(30000);
            connection.setDoInput(true);
            connection.setDoOutput(true);
            connection.setUseCaches(false);
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Connection", "Keep-Alive");
            connection.setRequestProperty("Charset", "UTF-8");
            connection.setRequestProperty("Content-Type",
                    "multipart/form-data;boundary=" + HTTP_BOUNDARY);

            Map<String, String> params = new HashMap<>();
            params.put("params1", "params1");
            params.put("params2", "params2");

            DataOutputStream outStream =
                    new DataOutputStream(connection.getOutputStream());
            outStream.writeBytes(appendPostParams(params).toString());
            outStream.flush();

            outStream.writeBytes(HTTP_START + HTTP_BOUNDARY + HTTP_END);
            String fileName = meeting.id + "-" + source + extractFullSuffix(name);
            outStream.writeBytes("Content-Disposition: form-data;" +
                    "name=\"wavFile\";filename=\"" + fileName + "\"" + HTTP_END);
            outStream.writeBytes(HTTP_END);

            FileInputStream inStream = new FileInputStream(file);
            byte[] buffer = new byte[8192];
            int length;
            while ((length = inStream.read(buffer)) != -1) {
                outStream.write(buffer, 0, length);
            }
            outStream.writeBytes(HTTP_END);
            outStream.writeBytes(HTTP_START + HTTP_BOUNDARY + HTTP_START + HTTP_END);

            inStream.close();
            outStream.flush();

            int code = connection.getResponseCode();
            LogUtil.d(TAG, "responseCode = " + code);

            InputStream responseStream = connection.getInputStream();
            StringBuilder sb = new StringBuilder();
            int data;
            while ((data = responseStream.read()) != -1) {
                sb.append((char) data);
            }
            LogUtil.d(TAG, "response: " + sb.toString());
            outStream.close();
            return true;
        } catch (Exception e) {
            LogUtil.e(TAG, "error upload file to server", e);
            return false;
        }
    }

    private StringBuilder appendPostParams(Map<String,String> params){
        StringBuilder sb = new StringBuilder();
        for (Map.Entry<String, String> entry : params.entrySet() ){
            sb.append(HTTP_START)
                    .append(HTTP_BOUNDARY)
                    .append(HTTP_END).append("Content-Disposition: form-data; name=\"")
                    .append(entry.getKey())
                    .append("\"")
                    .append(HTTP_END)
                    .append("Content-Type: text/plain; charset=UTF-8")
                    .append(HTTP_END)
                    .append("Content-Transfer-Encoding: 8bit")
                    .append(HTTP_END)
                    .append(HTTP_END)
                    .append(entry.getValue())
                    .append(HTTP_END);
        }
        return sb;
    }