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, the following code opens a connection to the site example.com
:
try { URL myURL = new URL("http://example.com/"); URLConnection myURLConnection = myURL.openConnection(); myURLConnection.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.