将InputStream转换为byte数组

感受不难，但用的时候一时半会写不出来，浪费时间，因而记录下来。

public static byte[] read(InputStream inputStream) throws IOException {
        try {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int num = inputStream.read(buffer);
            while (num != -1) {
                baos.write(buffer, 0, num);
                num = inputStream.read(buffer);
            }
            baos.flush();
            return baos.toByteArray();
        } finally {
            if (inputStream != null) {
                inputStream.close();
            }
        }
    }