Java HttpURLConnection - 列舉所有302重定向跳轉

Question

我的目標是使用java.net.HttpURLConnection來解析給定URL的所有302重定向躍點。

這是我的代碼片段（實際上，我用它在Talend SW）：

String url = row2.url; 
java.net.HttpURLConnection con = (java.net.HttpURLConnection) new java.net.URL(url).openConnection(); 
con.setInstanceFollowRedirects(false); 
con.connect(); 
String realURL = con.getHeaderField("Location"); 

System.out.println(realURL); 

它工作得很好，如果只有一個302的答覆。 例如，如果我填充row2.ulr =「https://jigsaw.w3.org/HTTP/300/302.html」代碼將輸出 - >https://jigsaw.w3.org/HTTP/300/Overview.html女巫是100％正確的。

我的問題是，我無法分析幾個302的回覆，一個典型的例子就是Facebook的網址： www.facebook.com/ID_account - > redirect-> www.facebook.com/ACCOUNT_NAME

使用重定向檢查網上我發現了2 - 302響應（我需要第二個）：

這是捲曲輸出：

> >>> http://www.facebook.com/123456789 
> 
> > -------------------------------------------- 
> > 302 Found 
> > -------------------------------------------- 
> 
> Status: 302 Found Code: 302 
> Location: https://www.facebook.com/123456789 Vary: Accept-Encoding 
> Content-Type: text/html; charset=UTF-8 
> X-FB-Debug: Muf4PfCP9TRKCO17QUf7SV2vsdnrCu6Gw2+sjWAKe0QPGdAToJPcmgH5LHv3NIAhzsJXfPB3a9/mVtuhiiEihA== 
> Date: Mon, 16 Oct 2017 16:02:55 GMT Connection: close 
> Content-Length: 0 
> 
> 
> 
> 
> >>> https://www.facebook.com/123456789 
> 
> > -------------------------------------------- 
> > 302 Found 
> > -------------------------------------------- 
> 
> Status: 302 Found Code: 302 X-XSS-Protection: 0 
> public-key-pins-report-only: max-age=600; 
> pin-sha256="WoiWRyIOVNa9ihaBciRSC7XHjliYS9VwUGOIud4PB18="; 
> pin-sha256="k2v657xBsOVe1PQRwOsHsw3bsGT2VzIqz5K+59sNQws="; 
> pin-sha256="gMxWOrX4PMQesK9qFNbYBxjBfjUvlkn/vN1n+L9lE5E="; 
> pin-sha256="q4PO2G2cbkZhZ82+JgmRUyGMoAeozA+BSXVXQWB8XWQ="; 
> report-uri="http://reports.fb.com/hpkp/" Pragma: no-cache 
> Location: https://www.facebook.com/a_name_account/ 
> Cache-Control: private, no-cache, no-store, must-revalidate 
> X-Frame-Options: DENY Strict-Transport-Security: max-age=15552000; 
> preload X-Content-Type-Options: nosniff Expires: Sat, 01 Jan 2000 
> 00:00:00 GMT Vary: Accept-Encoding Content-Type: text/html; 
> charset=UTF-8 
> X-FB-Debug: j2KCBNZ1poIJ0xUeeQYbinpcqq2avoI4z8eWb9Dx/yUUg98uyGYGadydia7en1s5X4DJeaJB7VjxYaRvP+psCw== 
> Date: Mon, 16 Oct 2017 16:02:55 GMT Connection: close 
> Content-Length: 0 
> 
> 
> 
> 
> >>> https://www.facebook.com/a_name_account/ 

如何找到第二個302的任何建議「要價較高離子「 - >https://www.facebook.com/a_name_account/？

在此先感謝 的REG S.

Answer 1

這將是一個偉大的Recursive Method行爲。

如果您確定響應頭中仍有位置，則可以繼續調用您的方法。

public void recurseLocation(String url) { 

    URL url = new URL(location); 
    HttpURLConnection connection = (HttpURLConnection) url.openConnection(); 
    connection.setInstanceFollowRedirects(false); 
    connection.connect(); 
    String newLocation = connection.getHeaderField("Location"); 

    if (newLocation != null) { 
     newLocation = recurseLocation(newLocation); 
    } else { 
     newLocation = location; 
    } 

    return newLocation; 
}