URLConnections - Java Network Programming - page 234

public static void main ( String [] args ) {
try {
URL u = new URL ( args [ 0 ]);
HttpURLConnection uc = ( HttpURLConnection ) u . openConnection ();
try ( InputStream raw = uc . getInputStream ()) {
printFromStream ( raw );
} catch ( IOException ex ) {
printFromStream ( uc . getErrorStream ());
}
} catch ( MalformedURLException ex ) {
System . err . println ( args [ 0 ] + " is not a parseable URL" );
} catch ( IOException ex ) {
System . err . println ( ex );
}
}
private static void printFromStream ( InputStream raw ) throws IOException {
try ( InputStream buffer = new BufferedInputStream ( raw )) {
Reader reader = new InputStreamReader ( buffer );
int c ;
while (( c = reader . read ()) != - 1 ) {
System . out . print (( char ) c );
}
}
}
}
Redirects
The 300-level response codes all indicate some sort of redirect; that is, the requested
resource is no longer available at the expected location but it may be found at some
other location. When encountering such a response, most browsers automatically load
the document from its new location. However, this can be a security risk, because it has
the potential to move the user from a trusted site to an untrusted one, perhaps without
the user even noticing.
By default, an HttpURLConnection follows redirects. However, the HttpURLConnec
tion class has two static methods that let you decide whether to follow redirects:
public static boolean getFollowRedirects ()
public static void setFollowRedirects ( boolean follow )
The getFollowRedirects() method returns true if redirects are being followed, false
if they aren't. With an argument of true , the setFollowRedirects() method makes
HttpURLConnection objects follow redirects. With an argument of false , it prevents
them from following redirects. Because these are static methods, they change the be‐
havior of all HttpURLConnection objects constructed after the method is invoked. The
setFollowRedirects() method may throw a SecurityException if the security man‐
ager disallows the change. Applets especially are not allowed to change this value.