/**

     * 从网络Url中下载文件

     * @param urlStr   指定的url

     * @param fileName    下载文件到本地的名字

     * @param savePath     本地保存下载文件的路径

     * @throws IOException

     */

    public static void  downLoadFromUrl(String urlStr,String fileName,String savePath) throws IOException{

        URL url = new URL(urlStr);

        HttpURLConnection conn = (HttpURLConnection)url.openConnection();

        //设置超时间为3秒

        //conn.setConnectTimeout(3*1000);

        //防止屏蔽程序抓取而返回403错误

        //conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");

        //得到输入流

        InputStream inputStream = conn.getInputStream();

        //获取自己数组

        byte[] getData = readInputStream(inputStream);

        //文件保存位置

        File saveDir = new File(savePath);

        if(!saveDir.exists()){

            saveDir.mkdir();

        }

        File file = new File(saveDir+File.separator+fileName);

        FileOutputStream fos = new FileOutputStream(file);

        fos.write(getData);

        if(fos!=null){

            fos.close();

        }

        if(inputStream!=null){

            inputStream.close();

        }

        System.out.println("info:"+url+" download success");

    }

    /**

     * 从输入流中获取字节数组

     * @param inputStream

     * @return

     * @throws IOException

     */

    public static  byte[] readInputStream(InputStream inputStream) throws IOException {

        byte[] buffer = new byte[1024];

        int len = 0;

        ByteArrayOutputStream bos = new ByteArrayOutputStream();

        while((len = inputStream.read(buffer)) != -1) {

            bos.write(buffer, 0, len);

        }

        bos.close();

        return bos.toByteArray();

    }

　　//main函数测试

　　public static void main(String[] args) throws IOException {

        downLoadFromUrl("http://baidu.pdf","lq.pdf","d:/file/");

        //System.out.println(111);

    }