问语音识别 POST返回汉字乱码问题？

public static String sendVoice() {
        Map<String, String> reqMap = new TreeMap();
        reqMap.put("Action", "SentenceRecognition");
        reqMap.put("SecretId", SecretId);
        reqMap.put("Timestamp", toUNIXEpoch());
        reqMap.put("Nonce", toUNIXNonce());
        reqMap.put("Version", "2018-05-22");
        reqMap.put("ProjectId", "0");
        reqMap.put("SubServiceType", "2");
        reqMap.put("EngSerViceType", EngSerViceType);
        reqMap.put("SourceType", SourceType);
        if (SourceType.compareTo("0") == 0) {
            try {
                String Url = URLEncoder.encode(fileURI, "UTF-8");
                reqMap.put("Url", Url);
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
        } else if (SourceType.compareTo("1") == 0) {
            FileInputStream fileInputStream = null;
            try {
                fileInputStream = new FileInputStream(new File(fileURI));
                int datalen = fileInputStream.available();
                byte[] dataPacket = new byte[datalen];
                int n = fileInputStream.read(dataPacket);
                //System.out.println("n :"+n);
                String Data = Base64.getEncoder().encodeToString(dataPacket);
                String DataLen = datalen + "";
                // System.out.println("data len: "+DataLen);
                reqMap.put("Data", Data);
                reqMap.put("DataLen", DataLen);


            } catch (Exception e) {
                e.printStackTrace();
            }
        } else {
            return "-3";
        }
        reqMap.put("VoiceFormat", VoiceFormat);
        String UsrAudioKey = getRandomString(16);
        reqMap.put("UsrAudioKey", UsrAudioKey);
        String _url = "POSTaai.tencentcloudapi.com/?";
        String signstr = formSignstr(_url, reqMap);
        // System.out.println("signstr: " + signstr);
        String signing = createSign(signstr, SecretKey);
        // System.out.println("签名: " + signing);
        String tmppostdata = formPostbody(reqMap);
        String sign = "";
        try {
            sign = URLEncoder.encode(signing, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        StringBuilder postdata = new StringBuilder(tmppostdata);
        postdata.append("Signature=");
        postdata.append(sign);
        String post = postdata.toString();
        //System.out.println("post : "+post);
        String serverUrl = "https://aai.tencentcloudapi.com";

        HttpURLConnection con = null;
        StringBuilder sbResult = new StringBuilder();
        try {
            URL url = new URL(serverUrl);
            con = (HttpURLConnection) url.openConnection();
            con.setRequestMethod("POST");
            con.setDoOutput(true);
            con.setDoInput(true);
            con.setUseCaches(false);
            con.setRequestProperty("Host", "aai.tencentcloudapi.com");
            con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            con.setRequestProperty("Charset", "UTF-8");
            con.setRequestProperty("Accept-Charset", "UTF-8");
            con.setRequestProperty("contentType", "UTF-8");

            // 往服务器写入数据
            OutputStream out = con.getOutputStream();
            out.write(post.getBytes("UTF-8"));
            out.flush();

            // 接收服务器返回的数据
            InputStream in = con.getInputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(in,"UTF-8"));
            String line;// 每一行的数据
            while ((line = br.readLine()) != null) {
                sbResult.append(line);
            }
            System.out.println(sbResult.toString());
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            if (con != null) {
                con.disconnect();
                con = null;
            }
        }
        //return "0";
        //return new String (sbResult.toString().getBytes(),"GBK");
        return sbResult.toString();
    }