After you've successfully created aURL
object, you can call theURL
object'sopenConnection
method to get aURLConnection
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 theURLConnection.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:A newtry { 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 . . . }URLConnection
object is created every time by calling theopenConnection
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, likegetInputStream
,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.