Getting "java.net.ProtocolException: Server redirected too many times" Error
Solution 1
It's apparently redirecting in an infinite loop because you don't maintain the user session. The session is usually backed by a cookie. You need to create a CookieManager
before you use URLConnection
.
// First set the default cookie manager.
CookieHandler.setDefault(new CookieManager(null, CookiePolicy.ACCEPT_ALL));
// All the following subsequent URLConnections will use the same cookie manager.
URLConnection connection = new URL(url).openConnection();
// ...
connection = new URL(url).openConnection();
// ...
connection = new URL(url).openConnection();
// ...
See also:
Solution 2
Duse, I have add this lines:
java.net.CookieManager cm = new java.net.CookieManager();
java.net.CookieHandler.setDefault(cm);
See this example:
java.net.CookieManager cm = new java.net.CookieManager();
java.net.CookieHandler.setDefault(cm);
String buf="";
dk = new DAKABrowser(input.getText());
try {
URL url = new URL(dk.toURL(input.getText()));
DataInputStream dis = new DataInputStream(url.openStream());
String inputLine;
while ((inputLine = dis.readLine()) != null) {
buf+=inputLine;
output.append(inputLine+"\n");
}
dis.close();
}
catch (MalformedURLException me) {
System.out.println("MalformedURLException: " + me);
}
catch (IOException ioe) {
System.out.println("IOException: " + ioe);
}
titulo.setText(dk.getTitle(buf));
Solution 3
I was using Jenkins on Tomcat6 on a unix environment and got this bug. For some reason, upgrading to Java7 solved it. I'd be interested to know exactly why that fixed it.
rjcarr
Updated on August 30, 2020Comments
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rjcarr over 3 years
I'm making a simple URL request with code like this:
URL url = new URL(webpage); URLConnection urlConnection = url.openConnection(); InputStream is = urlConnection.getInputStream();
But on that last line, I'm getting the "redirected too many times error". If my "webpage" var is, say, google.com then it works fine, but when I try to use my servlet's URL then it fails. It seems I can adjust the number of times it follows the redirects (default is 20) with this:
System.setProperty("http.maxRedirects", "100");
But when I crank it up to, say, 100 it definitely takes longer to throw the error so I know it is trying. However, the URL to my servlet works fine in (any) browser and using the "persist" option in firebug it seems to only be redirecting once.
A bit more info on my servlet ... it is running in tomcat and fronted by apache using 'mod-proxy-ajp'. Also of note, it is using form authentication so any URL you enter should redirect you to the login page. As I said, this works correctly in all browsers, but for some reason the redirect isn't working with the URLConnection in Java 6.
Thanks for reading ... ideas?
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rjcarr almost 12 yearsAs dbf said in the comments, the problem was indeed related to cookies. What you posted here is essentially the solution I used so I'll mark this as the accepted answer. Wish I could give an assist to dbf. :)