public void downPhotos(String url, String path, String photosName) throws IOException {
    long fileSize;
File out = new File(path, photosName + ".jpg");
URL myURL = new URL(url);
URLConnection conn = myURL.openConnection();
conn.connect();
InputStream is = conn.getInputStream();
fileSize = conn.getContentLength();
 
    if (fileSize <= 0)
        throw new RuntimeException("can not know the file`s size");
    if (is == null)
        throw new RuntimeException("stream is null");
FileOutputStream fos = new FileOutputStream(out);
    byte buf[] = new byte[1024];
    do {
        // 迴圈讀取
int numread = is.read(buf);
 
        if (numread == -1) {
            break;
}
        fos.write(buf, 0, numread);
} while (true);
    try {
        is.close();
} catch (Exception ex) {
        ex.printStackTrace();
}
}