很多時候，下載檔案時會重定向，並且要求攜帶cookie才允許下載，這種情況下，如果讓下載支援重定向，並且設定cookie呢？下面的程式碼可以供大家參考。

    public static void main(String[] args) throws Exception {
        String cookie = "";
        HttpURLConnection conn = null;
        do {
            URL url = new URL("***");
            conn = (HttpURLConnection) url.openConnection();
            //設定超時間為3秒
 

            conn.setConnectTimeout(3*1000);
            //防止遮蔽程式抓取而返回403錯誤
            conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
            conn.setInstanceFollowRedirects(false);
            if (cookie.length() != 0) {
                conn.setRequestProperty("Cookie"
 
, cookie);
            }
            int code = conn.getResponseCode();
            if (code == HttpURLConnection.HTTP_MOVED_TEMP) {
                for (int i = 1; i < conn.getHeaderFields().size(); i++) {
                    if (conn.getHeaderFieldKey(i).equalsIgnoreCase("set-cookie")) {
                        cookie += conn.getHeaderField(i) + ";"
 
;
                    }
                }
            }
            if (conn.getResponseCode() == HttpURLConnection.HTTP_OK)
                break;
        } while(true);

        //得到輸入流
        InputStream inputStream = conn.getInputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while((len = inputStream.read(buffer)) != -1) {
            System.out.println(len);
        }
        if(inputStream!=null){
            inputStream.close();
        }
    }