Connecting to a URL

After you've successfully created a URL object, you can call the URL object's openConnection method to get a URLConnection object, or one of its protocol specific subclasses, e.g. java.net.HttpURLConnection You can use this URLConnection object to setup parameters and general request properties that you may need before connecting. Connection to the remote object represented by the URL is only initiated when the URLConnection.connect method is called. When you do this you are initializing a communication link between your Java program and the URL over the network. For example, you can open a connection to the Yahoo site with the following code:

try {
    URL yahoo = new URL("http://www.yahoo.com/");
    URLConnection yahooConnection = yahoo.openConnection();
    yahooConnection.connect();

} catch (MalformedURLException e) {     // new URL() failed
    . . .
} catch (IOException e) {               // openConnection() failed
    . . .
}

A new URLConnection object is created every time by calling the openConnection method of the protocol handler for this URL. You are not always required to explicitly call the connect method to initiate the connection. Operations that depend on being connected, like getInputStream, getOutputStream, etc, will implicitly perform the connection, if necessary.
Now that you've successfully connected to your URL, you can use the URLConnection object to perform actions such as reading from or writing to the connection. The next section shows you how.