code: public static InputStream getStream(URL url) {
  		Assert.notNull(url);
  		try {
  			return url.openStream();
  		} catch (IOException e) {
  			throw new IORuntimeException(e);
  		}
  	}
docs: 从URL中获取流
  
  @param url {@link URL}
  @return InputStream流
  @since 3.2.1