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The Java EE 6 Tutorial

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.

The simplegreeting Source Files

The four source files for the simplegreeting example are

The source files are located in the following directory:

tut-install/examples/cdi/simplegreeting/src/java/greetings

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 xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:ui="http://java.sun.com/jsf/facelets">
    <h:head>
        <meta http-equiv="Content-Type" 
              content="text/html; charset=UTF-8"/>
        <link href="resources/css/default.css" 
              rel="stylesheet" type="text/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 xmlns="http://www.w3.org/1999/xhtml"
      xmlns:ui="http://java.sun.com/jsf/facelets"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:f="http://java.sun.com/jsf/core">
    <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 type 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 typed by the user:


Hello, name.
 

Hi, name!

The Facelets page and template are located in the following directory:

tut-install/examples/cdi/simplegreeting/web

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

tut-install/examples/cdi/simplegreeting/web/resources/css/default.css

Configuration Files

You must create an empty beans.xml file to indicate to GlassFish Server that your application is a CDI application. This file can have content in some situations, but not in simple applications like this one.

Your application also needs the basic web application deployment descriptors web.xml and sun-web.xml. These configuration files are located in the following directory:

tut-install/examples/cdi/simplegreeting/web/WEB-INF

Building, Packaging, Deploying, and Running the simplegreeting CDI Example

You can build, package, deploy, and run the simplegreeting application by using either NetBeans IDE or the Ant tool.

ProcedureTo Build, Package, and Deploy the simplegreeting Example Using NetBeans IDE

This procedure builds the application into the following directory:

tut-install/examples/cdi/simplegreeting/build/web

The contents of this directory are deployed to the GlassFish Server.

  1. In NetBeans IDE, select File->Open Project.

  2. In the Open Project dialog, navigate to:


    tut-install/examples/cdi/

  3. Select the simplegreeting folder.

  4. Select the Open as Main Project check box.

  5. Click Open Project.

  6. (Optional) 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 edit pane, comment out the @Informal annotation:

      //@Informal
@Inject
Greeting greeting;

    5. Save the file.

  7. In the Projects tab, right-click the simplegreeting project and select Deploy.

ProcedureTo Build, Package, and Deploy the simplegreeting Example Using Ant

  1. In a terminal window, go to:


    tut-install/examples/cdi/simplegreeting/

  2. Type the following command:


    ant

    This command calls the default target, which builds and packages the application into a WAR file, simplegreeting.war, located in the dist directory.

  3. Type the following command:


    ant deploy

    Typing this command deploys simplegreeting.war to the GlassFish Server.

ProcedureTo Run the simplegreeting Example

  1. In a web browser, type the following URL:


    http://localhost:8080/simplegreeting

    The Simple Greeting page opens.

  2. Type a name in the text field.

    For example, suppose that you type Duke.

  3. Click the Say Hello button.

    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.

    Figure 19–1 shows what the application looks like if you did not modify the Printer.java file.

    Figure 19–1 Simple Greeting Application

    Simple Greeting application