android从Socket流读取文件数据，按照头标记拆分byte数组

 public static String readCMDFromSocket(InputStream in) {
    // 8M
    int MAX_BUFFER_BYTES = 1024 * 1024*8;
    String msg = "";
    byte[] tempbuffer = new byte[MAX_BUFFER_BYTES];
    try {
        int numReadedBytes = in.read(tempbuffer, 0, tempbuffer.length);
        msg = new String(tempbuffer, 0, numReadedBytes, "utf-8");
        // 报文总长度
        long msgLenth = 0;
        // 已经读取的长度
        long readLenth = numReadedBytes;
        if (!"".equals(msg)) {
            msgLenth = Long.valueOf(msg.substring(0, 8));
            msg = msg.substring(8, msg.length());
            while (readLenth < msgLenth) {
                // 一直读取
                int newReadedBytes = in.read(tempbuffer, 0, tempbuffer.length);
                msg += new String(tempbuffer, 0, newReadedBytes, "utf-8");
                // 直到已经读取的总长度等于总长度，不再读取
                readLenth += newReadedBytes;
            }
        }
        Log.e("TAG", "readCMDFromSocket: " + tempbuffer.length + "-----" + numReadedBytes);
        return msg;
    } catch (Exception e) {
        Log.e("TAG", Thread.currentThread().getName() + "---->" + "readFromSocket error");
        e.printStackTrace();
    }
    return null;
}

以上代码，是从Socket流读取完整数据

每次调用后台，只读取50K大小数据，防止一次性读取多，数据不完整，解析失败。

private void pollResult(BufferedOutputStream out) throws IOException {
    // 从数据库，查出后台返回的结果
    String result = pollData(context, new SQLdm().openDatabase(context), 1);
    // 初始化
    byte[] bytes = result.getBytes("utf-8");

    // 命令左补齐8位+查询的结果，例00000000256
    result = String.format("%08d", bytes.length + 8) + result;
    bytes = result.getBytes("utf-8");

    if (bytes.length > 1024 * 50) {
        // 长度超过50K，拆分
        byte[][] bytes1 = splitBytes(bytes, 1024 * 50);
        for (int i = 0; i < bytes1.length; i++) {
            out.write(bytes1[i], 0, bytes1[i].length);
        }
        // 遍历输出，再清空缓存
        out.flush();
    } else {
       // 没有超过50K，直接输出流，清空缓存
        out.write(bytes, 0, bytes.length);
        out.flush();
    }
}

工具类方法 拆分byte[]数组，每次50K

   /**
     * 拆分byte数组
     *
     * @param bytes 要拆分的数组
     * @param size  要按几个组成一份
     * @return
     */
    public byte[][] splitBytes(byte[] bytes, int size) {
        double splitLength = Double.parseDouble(size + "");
        int arrayLength = (int) Math.ceil(bytes.length / splitLength);
        byte[][] result = new byte[arrayLength][];
        int from, to;
        for (int i = 0; i < arrayLength; i++) {
            from = (int) (i * splitLength);
            to = (int) (from + splitLength);
            if (to > bytes.length)
                to = bytes.length;
            result[i] = Arrays.copyOfRange(bytes, from, to);
        }
        return result;
    }

向后台发送数据，同样左补齐8位

public static String connectSuccess() throws Exception {
    JSONObject jsonObject = new JSONObject();
    jsonObject.put("code", "00");
    jsonObject.put("message", "成功");
    // 设置发送的内容
    String outJsonData = jsonObject.toString();

    byte[] bytes = outJsonData.getBytes("utf-8");
    // 左补齐8位置，发送Json串
    outJsonData = String.format("%08d", bytes.length + 8) + outJsonData;
    return outJsonData;
}