The Java EE 7 Tutorial

24.1 The simplegreeting CDI Example

The simplegreeting example illustrates some of the most basic features of CDI: scopes, qualifiers, bean injection, and accessing a managed bean in a JavaServer Faces application. When you run the example, you click a button that presents either a formal or an informal greeting, depending on how you edited one of the classes. The example includes four source files, a Facelets page and template, and configuration files.

24.1.1 The simplegreeting Source Files

The four source files for the simplegreeting example are

The default Greeting class, shown in Beans as Injectable Objects
The @Informal qualifier interface definition and the InformalGreeting class that implements the interface, both shown in Using Qualifiers
The Printer managed bean class, which injects one of the two interfaces, shown in full in Adding Setter and Getter Methods

The source files are located in the tut-install/examples/cdi/simplegreeting/src/main/java/javaeetutorial/simplegreeting directory.

24.1.2 The Facelets Template and Page

To use the managed bean in a simple Facelets application, you can use a very simple template file and index.xhtml page. The template page, template.xhtml, looks like this:

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
          "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="en"
      xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://xmlns.jcp.org/jsf/html"
      xmlns:ui="http://xmlns.jcp.org/jsf/facelets">
    <h:head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
        <h:outputStylesheet library="css" name="default.css"/>
        <title><ui:insert name="title">Default Title</ui:insert></title>
    </h:head>

    <body>
        <div id="container">
            <div id="header">
                <h2><ui:insert name="head">Head</ui:insert></h2>
            </div>

            <div id="space">
                <p></p>
            </div>

            <div id="content">
                <ui:insert name="content"/>
            </div>
        </div>
    </body>
</html>

To create the Facelets page, you can redefine the title and head, then add a small form to the content:

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
          "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="en"
      xmlns="http://www.w3.org/1999/xhtml"
      xmlns:ui="http://xmlns.jcp.org/jsf/facelets"
      xmlns:h="http://xmlns.jcp.org/jsf/html">
    <ui:composition template="/template.xhtml">

        <ui:define name="title">Simple Greeting</ui:define>
        <ui:define name="head">Simple Greeting</ui:define>
        <ui:define name="content">
            <h:form id="greetme">
               <p><h:outputLabel value="Enter your name: " for="name"/>
                  <h:inputText id="name" value="#{printer.name}"/></p>
               <p><h:commandButton value="Say Hello" 
                                   action="#{printer.createSalutation}"/></p>
               <p><h:outputText value="#{printer.salutation}"/> </p>
            </h:form>
        </ui:define>

    </ui:composition>
</html>

The form asks the user to enter a name. The button is labeled Say Hello, and the action defined for it is to call the createSalutation method of the Printer managed bean. This method in turn calls the greet method of the defined Greeting class.

The output text for the form is the value of the greeting returned by the setter method. Depending on whether the default or the @Informal version of the greeting is injected, this is one of the following, where name is the name entered by the user:

Hello, name.

Hi, name!

The Facelets page and template are located in the tut-install/examples/cdi/simplegreeting/src/main/webapp/ directory.

The simple CSS file that is used by the Facelets page is in the following location:

tut-install/examples/cdi/simplegreeting/src/main/webapp/resources/css/default.css

24.1.3 Running the simplegreeting Example

You can use either NetBeans IDE or Maven to build, package, deploy, and run the simplegreeting application.

24.1.3.1 To Build, Package, and Run the simplegreeting Example Using NetBeans IDE

Make sure that GlassFish Server has been started (see Starting and Stopping GlassFish Server).
From the File menu, choose Open Project.
In the Open Project dialog box, navigate to:
```
tut-install/examples/cdi
```
Select the simplegreeting folder.
Click Open Project.
To modify the Printer.java file, perform these steps:
1. Expand the Source Packages node.
2. Expand the greetings node.
3. Double-click the Printer.java file.
4. In the editor, comment out the @Informal annotation:
```
@Inject
//@Informal
Greeting greeting;
```
5. Save the file.
In the Projects tab, right-click the simplegreeting project and select Build.

This command builds and packages the application into a WAR file, simplegreeting.war, located in the target directory, and then deploys it to GlassFish Server.

24.1.3.2 To Build, Package, and Deploy the simplegreeting Example Using Maven

Make sure that GlassFish Server has been started (see Starting and Stopping GlassFish Server).

In a terminal window, go to:

tut-install/examples/cdi/simplegreeting/

Enter the following command to deploy the application:
```
mvn install
```
This command builds and packages the application into a WAR file, simplegreeting.war, located in the target directory, and then deploys it to GlassFish Server.

24.1.3.3 To Run the simplegreeting Example

In a web browser, enter the following URL:
```
http://localhost:8080/simplegreeting
```
The Simple Greeting page opens.
Enter a name in the field.

For example, suppose that you enter Duke.
Click Say Hello.

If you did not modify the Printer.java file, the following text string appears below the button:
```
Hi, Duke!
```
If you commented out the @Informal annotation in the Printer.java file, the following text string appears below the button:
```
Hello, Duke.
```

Release: Java EE 7.0