按照给的demo进行编码

HttpURLConnection conn = (HttpURLConnection) new URL(serverURL).openConnection();
// construct params
JSONObject params = new JSONObject();
params.put("format", "pcm");
params.put("rate", 16000);
params.put("channel", "1");
params.put("token", token);
params.put("cuid", cuid);
params.put("len", file.length());

//params.put("speech", DatatypeConverter.printBase64Binary(loadFile(pcmFile)));
params.put("speech", com.baidu.tts.tools.Base64.encode(loadFile(file),"utf-8").replace('\n',' ').trim());
//params.put("speech", Base64.encode(loadFile(file),Base64.DEFAULT));
Log.e(TAG,params.toString());
// add request header
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/json; charset=utf-8");

conn.setDoInput(true);
conn.setDoOutput(true);

// send request
DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
wr.writeBytes(params.toString());
wr.flush();
wr.close();

其中Base64用的是SDK自带的，但是一直回复3300错误，请大家看看