java urlconnection獲取最終重定向的URL

Question

我有一個重定向到另一個網址的網址。我希望能夠獲得最終重定向的網址。我的代碼：

    public class testURLConnection
    {
    public static void main(String[] args) throws MalformedURLException, IOException {

    HttpURLConnection con =(HttpURLConnection) new URL( "http://tinyurl.com/KindleWireless" ).openConnection();

    System.out.println( "orignal url: " + con.getURL() );
    con.connect();

System.out.println( "connected url: " + con.getURL() );
InputStream is = con.getInputStream();
System.out.println( "redirected url: " + con.getURL() );
is.close();

}}

它始終提供原始URL，而redirectURL為： http ：//www.amazon.com/Kindle-Wireless-Reading-Display-Globally/dp/B003FSUDM4/ref=amb_link_353259562_2?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-10&pf_rd_r=11EYKT662A79T370AM3&pf_rd_t=201&pf_rd_p = 1270985982＆pf_rd_i = B002Y27P3M 。

如何獲得此最終重定向的URL。

這是我嘗試循環直到我們得到重定向.Still doesent獲取所需的URL：

    public static String fetchRedirectURL(String url) throws IOException
    {
HttpURLConnection con =(HttpURLConnection) new URL( url ).openConnection();
//System.out.println( "orignal url: " + con.getURL() );
con.setInstanceFollowRedirects(false);
con.connect();


InputStream is = con.getInputStream();
if(con.getResponseCode()==301)
    return con.getHeaderField("Location");
else return null;
    }
    public static void main(String[] args) throws MalformedURLException, IOException {
String url="http://tinyurl.com/KindleWireless";
String fetchedUrl=fetchRedirectURL(url);
System.out.println("FetchedURL is:"+fetchedUrl);
while(fetchedUrl!=null)
{   url=fetchedUrl;
System.out.println("The url is:"+url);
    fetchedUrl=fetchRedirectURL(url);


}
System.out.println(url);

    }

Answer 1

試試這個，我遞歸地使用許多重定向URL。

public static String getFinalURL(String url) throws IOException {
    HttpURLConnection con = (HttpURLConnection) new URL(url).openConnection();
    con.setInstanceFollowRedirects(false);
    con.connect();
    con.getInputStream();

    if (con.getResponseCode() == HttpURLConnection.HTTP_MOVED_PERM || con.getResponseCode() == HttpURLConnection.HTTP_MOVED_TEMP) {
        String redirectUrl = con.getHeaderField("Location");
        return getFinalURL(redirectUrl);
    }
    return url;
}

和使用：

public static void main(String[] args) throws MalformedURLException, IOException {
    String fetchedUrl = getFinalURL("<your_url_here>");
    System.out.println("FetchedURL is:" + fetchedUrl);

}

Answer 2

public static String getFinalRedirectedUrl(String url) {

    HttpURLConnection connection;
    String finalUrl = url;
    try {
        do {
            connection = (HttpURLConnection) new URL(finalUrl)
                    .openConnection();
            connection.setInstanceFollowRedirects(false);
            connection.setUseCaches(false);
            connection.setRequestMethod("GET");
            connection.connect();
            int responseCode = connection.getResponseCode();
            if (responseCode >= 300 && responseCode < 400) {
                String redirectedUrl = connection.getHeaderField("Location");
                if (null == redirectedUrl)
                    break;
                finalUrl = redirectedUrl;
                System.out.println("redirected url: " + finalUrl);
            } else
                break;
        } while (connection.getResponseCode() != HttpURLConnection.HTTP_OK);
        connection.disconnect();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return finalUrl;
}

Answer 3

我的第一個想法是將instanceFollowRedirects設置為false，或者使用URLConnection 。

在這兩種情況下，重定向都不會被執行，因此您將收到對原始請求的回復。 獲取HTTP狀態值，如果是3xx，則獲取新的重定向值。

當然可能存在一系列重定向，因此您可能希望迭代直到到達真實（狀態2xx）頁面。

Answer 4

@ user719950在我的MAC-OSX上 - 這解決了截斷的HTTP URL的問題：

對於您的原始代碼，只需在以下行中添加：//您必須通過瀏覽器找到IE / Chrome正在發送的請求標頭。 我仍然沒有解釋為什么這個簡單的設置導致正確的URL :)

HttpURLConnection con =(HttpURLConnection) new URL
( "http://tinyurl.com/KindleWireless" ).openConnection();
 con.setInstanceFollowRedirects(true);
 con.setDoOutput(true);
  System.out.println( "orignal url: " + con.getURL() );     
         **con.setRequestProperty("User-Agent",
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) 
    AppleWebKit/536.26.17 (KHTML, like Gecko) Version/6.0.2  
   Safari/536.26.17");**                  

           con.connect();
    System.out.println( "connected url: " + con.getURL() );
    Thread.currentThread().sleep(2000l);
    InputStream is = con.getInputStream();
    System.out.println( "redirected url: " + con.getURL() );

    is.close();

Answer 5

這可能有所幫助

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

HttpURLConnection con = (HttpURLConnection) new URL(
        "http://tinyurl.com/KindleWireless").openConnection(proxy);
    System.out.println("orignal url: " + con.getURL());
    con.connect();
    con.setInstanceFollowRedirects(false);
    int responseCode = con.getResponseCode();
    if ((responseCode / 100) == 3) {
        String newLocationHeader = con.getHeaderField("Location");
        responseCode = con.getResponseCode();
        System.out.println("Redirected Location " + newLocationHeader);
        System.out.println(responseCode);
    }

}

Answer 6

@JEETS您的fetchRedirectURL函數可能無法正常工作，因為重定向有多種HTTP代碼。 將其更改為范圍檢查，它將起作用。

public static String fetchRedirectURL(String url) throws IOException
    {
HttpURLConnection con =(HttpURLConnection) new URL( url ).openConnection();
//System.out.println( "orignal url: " + con.getURL() );
con.setInstanceFollowRedirects(false);
con.connect();

InputStream is = con.getInputStream();
if(con.getResponseCode()>=300 && con.getResponseCode() <400)
    return con.getHeaderField("Location");
else return null;
    }

Answer 7

如果有多個重定向，這個遞歸遞歸：

protected String getDirectUrl(String link) {
    String resultUrl = link;
    HttpURLConnection connection = null;
    try {
        connection = (HttpURLConnection) new URL(link).openConnection();
        connection.setInstanceFollowRedirects(false);
        connection.connect();
        int responseCode = connection.getResponseCode();
        if (responseCode == HttpURLConnection.HTTP_MOVED_PERM || responseCode == HttpURLConnection.HTTP_MOVED_TEMP) {
            String locationUrl = connection.getHeaderField("Location");

            if (locationUrl != null && locationUrl.trim().length() > 0) {
                IOUtils.close(connection);
                resultUrl = getDirectUrl(locationUrl);
            }
        }
    } catch (Exception e) {
        log("error getDirectUrl", e);
    } finally {
        IOUtils.close(connection);
    }
    return resultUrl;
}