的java的URLConnection得到最終的重定向的URL

Question

我有一個重定向到另一個url.I一個網址希望能夠獲得最後的重定向URL.My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(); 

}}

它總是給出原始的url，而redirectURL是：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=11EYKTN682A79T370AM3&pf_rd_t=201&pf_rd_p=1270985982&pf_rd_i=B002Y27P3M。

我怎樣才能得到這個最終重定向的URL。

這裏是我試圖與循環，直到我們得到redirects.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

我的第一個想法是設置instanceFollowRedirects爲false，或使用URLConnection代替。

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

當然，可能會有一連串的重定向，所以可能你會想迭代，直到你到達真實（狀態2xx）頁面。

Answer 2

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

你原來的代碼，只需添加此線以下：//你必須通過瀏覽器來查找是請求頭IE/Chrome正在發送。我仍然不具有解釋爲什麼這個簡單的設置導致正確的網址:)

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 3

這可能有助於

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 4

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 5

@JEETS 你fetchRedirectURL功能可能無法正常工作，因爲有各種HTTP代碼重定向。將其更改爲範圍檢查，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 6

這人去遞歸的情況下有多個重定向：

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; 
} 

Answer 7

試試這個，我用遞歸地使用了許多重定向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); 

}