从一个URL下载原始数据，基于byte字节，得到byte数组

public static byte[] loadRawDataFromURL(String u) throws Exception {        URL url = new URL(u);        HttpURLConnection conn = (HttpURLConnection) url.openConnection();        InputStream is = conn.getInputStream();        BufferedInputStream bis = new BufferedInputStream(is);        ByteArrayOutputStream baos = new ByteArrayOutputStream();　　　　　//缓存2KB        final int BUFFER_SIZE = 2*1024;        final int EOF = -1;        int c;        byte[] buf = new byte[BUFFER_SIZE];        while (true) {            c = bis.read(buf);            if (c == EOF)                break;            baos.write(buf, 0, c);        }        conn.disconnect();        is.close();        byte[] data = baos.toByteArray();        baos.flush();        return data;    }