Java 获取网络上的文件

/** * 获取网络上的图片 * @param URLName 地址 * @throws Exception */public InputStream getUrlImg(String URLName) throws Exception {ByteArrayOutputStream os = new ByteArrayOutputStream();int HttpResult = 0; //服务器返回的状态URL url = new URL(URLName); //创建URLURLConnection urlconn = url.openConnection(); // 试图连接并取得返回状态码urlconn.connect();HttpURLConnection httpconn = (HttpURLConnection) urlconn;HttpResult = httpconn.getResponseCode();System.out.println(HttpResult);if (HttpResult != HttpURLConnection.HTTP_OK){  //不等于HTTP_OK说明连接不成功System.out.print("连接失败！");}else {int filesize = urlconn.getContentLength();  //取数据长度System.out.println(filesize); BufferedInputStream bis=new BufferedInputStream(urlconn.getInputStream()); BufferedOutputStream bos=new BufferedOutputStream(os);byte[] buffer = new byte[1024]; //创建存放输入流的缓冲int num = -1; //读入的字节数while (true) {num = bis.read(buffer); // 读入到缓冲区if (num ==-1){bos.flush();break; //已经读完}bos.flush();bos.write(buffer,0,num);}bos.close();bis.close();  }  ByteArrayInputStream bis = new ByteArrayInputStream(os.toByteArray());  return bis;}