根据网络图片地址获取资源的字节流

/**
 * 根据地址获得数据的字节流
 * @param strUrl 网络连接地址
 * @return
 */
private static byte[] getImageFromNetByUrl(String strUrl){
    try {
        URL url = new URL(strUrl);
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        conn.setRequestMethod("GET");
        conn.setConnectTimeout(5 * 1000);
        InputStream inStream = conn.getInputStream();//通过输入流获取图片数据
        byte[] btImg = readInputStream(inStream);//得到图片的二进制数据
        return btImg;
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

/**
 * 从输入流中获取数据
 * @param inStream 输入流
 * @return
 * @throws Exception
 */
private static byte[] readInputStream(InputStream inStream) throws Exception{
    ByteArrayOutputStream outStream = new ByteArrayOutputStream();
    byte[] buffer = new byte[1024];
    int len = 0;
    while( (len=inStream.read(buffer)) != -1 ){
        outStream.write(buffer, 0, len);
    }
    inStream.close();
    return outStream.toByteArray();
}