HomeApache Page 5 - Apache Tapestry and Listener Methods, Conditional Components and PageLink
Deploying the application - Apache
Today we continue to explore some of the most fundamental concepts of Tapestry while building one of the simplest Java Web applications. In the previous part of this tutorial we became familiar with properties of Tapestry pages and different ways to configure them. Now we’ll look into the details of writing listener methods.
Most Web applications are created to be deployed on the Web, and this is exactly what we are going to do with GuessTheWord.
First of all, we need to find a hosting provider. Fortunately, there are providers who make Java Web hosting available for free. Actually, I know just one of them – Eatj.com (if you know any other Java Web hosting provider who offers a free plan, please leave a note at the discussions page).
It is very easy to open a trial account with Eatj.com. Visit their website, and right on the home page you will see the “CREATE NEW ACCOUNT” form. Enter some username, and an email address where you will want to receive a message with information and choose a password. Read terms and conditions, then press the Register button.
Very soon you will receive an email with a link in it. You need to click that link to confirm your registration. In a minute or so you’ll receive another email with some useful links in it. You will find their “Getting Started” instructions and FAQ, but you can read all that later. Right now, simply go back to Eatj.com and log in with your selected username and password.
You will find yourself at the “My Account” page:
Note the “UPLOAD WAR FILES” header. This is exactly how we are going to deploy our application – as a WAR (which means “Web archive”) file. We don’t need to do anything special to create a WAR file because such a file is created automatically by NetBeans (and then deployed to its bundled Tomcat) every time we run our application in NetBeans. All we need to do is locate where this file is stored in our file system.
In the Files view of NetBeans, expand the GuessTheWord node and the dist subfolder. You will see the GuessTheWord.war file in it:
On your computer, this file is located in the folder you have chosen for NetBeans projects, in the GuessTheWord/dist subfolder.
Now, press the Choose File button on the My Account page of Eatj.com. Navigate to the GuessTheWord.war file wherever you have it on your computer and choose it. Then press the Upload button.
The upload itself will take quite some time despite the fact that the application is small. This is because the package contains all Tapestry libraries in it – a few megabytes of goodies. If you had your own server, or at least you had control over which libraries are available to your hosting provider’s Tomcat, you could upload only the application itself, without libraries, but this is not the case with Eatj.com. You can’t have everything for free!
When the upload completes, you should see the message: “Upload successful. Please restart your server.” When you restart Tomcat, it will pick up the WAR file you’ve just uploaded and deploy it properly. Under the “SERVER MAINTENANCE” header you will see the “RESTART” link – click on it and wait.
Finally, you should see a message stating that your server was restarted and giving you a link to your website. I have chosen username tttest, so my message looks like this:
Your server (tttest) has been restarted.
Click the link to see your home page:
However, if you follow the provided link, you will see the default page of the Tomcat Web server with a funny cat picture on it, but not the application we have just uploaded. To see the application itself, we need to add the /GuessTheWord context path to the link. In my case, the URL will be http://tttest.s42.eatj.com/GuessTheWord. Navigate to your application’s URL and – hurray! – you will see it working.
Isn’t it incredible – we have just created a Tapestry application, and it is already working on the Internet! You can invite your friends and relatives to see what a cool Java Web developer you are. However, in a few hours they will tell you that the application doesn’t respond anymore. This is because on trial accounts Eatj shuts down Tomcats four times a day (see their FAQ for details). But you can always log in, restart Tomcat, and everything will be working again.
What comes next
We shall continue our study of Tapestry components, gradually passing from the most simple to slightly more complicated. In the next part, I am going to show you two very useful components: For and DirectLink. We are also going to create a new application to play with them.