java-ee Getting started with java-ee Building my First JavaEE Application (Hello World)
Example
Let's understand something. JavaEE consists of a number of specifications. When you install an Application Server (Payara for example), you install all of the specifications at once. For example there's a specification for an ORM called JPA (Java Persistence API), a specification to build Component Based Web Applications called JSF (Java Server Faces), a specification to build REST web services and clients called JAX-RS.
So as you might guess, there's not only one way to build a simple Hello World application in JavaEE.
Secondly, the JavaEE spec has a specific structure of folders that looks something like this (simplified):
/projectname/src/main/java
/projectname/src/main/resources
/projectname/src/main/resources/META-INF
/projectname/src/main/webapp
/projectname/src/main/webapp/WEB-INF
Inside the /projectname/src/main/java we put all the java classes that we need.
Inside the /projectname/src/main/webapp we put html files, css files, javascript files, etc.
Inside the /projectname/src/main/webapp/WEB-INFgoes some optional configuration files, such as web.xml and beans.xml.
For simplicity we will use the NetBeans IDE (it's free) to build our first JavaEE Application. You can find it here. Choose the JavaEE version and install it.
Create new project
- Open NetBeans IDE
- Go to File > New Project > Maven > Web Application and click Next.
- Change project name to HelloJavaEE, then click Next and Finish.
Clean and build the project
- Go to Run > Clean and Build Project (HelloJavaEE).
Deploy the WAR file
- In a browser, go to http://localhost:4848 (follow instructions to install payara server).
- Go to Applications > Click Deploy, Click on Select File and choose your war file (HelloJavaEE-1.0-SNAPSHOT.war) under
../NetBeansProjects/HelloJavaEE/target.
Deploy the WAR file directly from Netbeans
- Install Payara (see next chapter).
- In Netbeans, go to the 'Services' tab (Window-> Services if you don't see it).
- Right-click on Servers and select 'Add Server...'
- Select 'GlassFish Server', give it a name and click next.
- Point to your local Payara installation, select 'Local Domain' and click next.
- Leave the domain location settings as they are (Domain: domain1, Host: localhost, DAS Port: 4848, HTTP Port: 8080).
- Go to the 'Projects' tab (Windows -> Projects).
- Right-click on your project and select 'Properties'.
- In the left hand pane, go to 'Run' and select the Server you just added.
- (Optional) Change the context path. If you set the context path to '/MyFirstApplication' the default URL will be 'http://localhost:8080/MyFirstApplication'.
View results
- In a browser, go to http://localhost:8080/HelloJavaEE-1.0-SNAPSHOT
Voila! That's your first app using JavaEE technology. You should now start creating other "Hello World" apps using different specifications like JPA, EJB, JAX-RS, JavaBatch, etc...
