URLConnections - Java Network Programming - page 209

public static boolean getDefaultAllowUserInteraction ()
public static FileNameMap getFileNameMap ()
public static void setFileNameMap ( FileNameMap map )
Unlike the instance methods, these methods can be invoked at any time. The new de‐
faults will apply only to URLConnection objects constructed after the new default values
are set.
protected URL url
The url field specifies the URL that this URLConnection connects to. The constructor
sets it when the URLConnection is created and it should not change thereafter. You can
retrieve the value by calling the getURL() method. Example 7-12 opens a URLConnec
tion to http://www.oreilly.com/ , gets the URL of that connection, and prints it.
Example 7-12. Print the URL of a URLConnection to http://www.oreilly.com/
import java.io.* ;
import java.net.* ;
public class URLPrinter {
public static void main ( String [] args ) {
try {
URL u = new URL ( "http://www.oreilly.com/" );
URLConnection uc = u . openConnection ();
System . out . println ( uc . getURL ());
} catch ( IOException ex ) {
System . err . println ( ex );
}
}
}
Here's the result, which should be no great surprise. The URL that is printed is the one
used to create the URLConnection .
% java URLPrinter
http://www.oreilly.com/
protected boolean connected
The boolean field connected is true if the connection is open and false if it's closed.
Because the connection has not yet been opened when a new URLConnection object is
created, its initial value is false . This variable can be accessed only by instances of
java.net.URLConnection and its subclasses.
There are no methods that directly read or change the value of connected . However,
any method that causes the URLConnection to connect should set this variable to true,
including connect() , getInputStream() , and getOutputStream() . Any method that