Java Platform, Enterprise Edition (Java EE) 8 The Java EE 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 following topics are addressed here:

- The simplegreeting Source Files

- The Facelets Template and Page

- Running the simplegreeting Example

### 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.

### The Facelets Template and Page

To use the managed bean in a simple Facelets application:

1. 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>

2. To create the Facelets page, 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

### Running the simplegreeting Example

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

The following topics are addressed here:

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

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

- To Run the simplegreeting Example

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

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

2. From the File menu, choose Open Project.

3. In the Open Project dialog box, navigate to:

       tut-install/examples/cdi

4. Select the `simplegreeting` folder.

5. Click Open Project.

6. 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.

7. 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.

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

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

2. In a terminal window, go to:

       tut-install/examples/cdi/simplegreeting/

3. 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.

#### To Run the simplegreeting Example

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

       http://localhost:8080/simplegreeting

   The Simple Greeting page opens.

2. Enter a name in the field.

   For example, suppose that you enter `Duke`.

3. Click Say Hello.

   If you did not modify the `Printer.java` file, then the following text string appears below the button:

       Hi, Duke!

   If you commented out the `@Informal` annotation in the `Printer.java` file, then the following text string appears below the button:

       Hello, Duke.

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