Assume for now that the server object is running remotely. To locate
it, you use Naming.lookup( )
,
passing in the lookup name. This gives you a reference to a
proxy object
, an object that, like
the real server object, implements the remote interface but runs in
the same Java Virtual Machine as your client application. Here we see
the beauty of interfaces: the proxy object implements the
interface, so your code
can use it just as it would use a local object providing the given
service. And the remote object also implements the interface, so the
proxy object’s remote counterpart can use it exactly as the
proxy is used. Example 22-2 shows the client for
the RemoteDate
service.
Example 22-2. DateClient.java
package darwinsys.distdate; import java.rmi.*; import java.util.*; /* A very simple client for the RemoteDate service. */ public class DateClient { /** The local proxy for the service. */ protected static RemoteDate netConn = null; public static void main(String[] args) { try { netConn = (RemoteDate)Naming.lookup(RemoteDate.LOOKUPNAME); Date today = netConn.getRemoteDate( ); System.out.println(today.toString( )); // XX use a DateFormat... } catch (Exception e) { System.err.println("RemoteDate exception: " + e.getMessage( )); e.printStackTrace( ); } } }
Also in the online source/RMI directory are
DateApplet.htm
and
DateApplet.java
, which together provide an
example of using the server. In DateApplet
, the
connection is set up in the applet’s init( )
method. The actual RMI call is done at the start of paint( )
, so it is updated any time the screen is painted.
3.145.179.35