Arun Gupta, Miles to go ...

TOTD #94: A simple Java Server Faces 2.0 + JPA 2.0 application - Getting Started with Java EE 6 using NetBeans 6.8 M1 & GlassFish v3

TOTD #93 showed how to get started with Java EE 6 using NetBeans 6.8 M1 and GlassFish v3 by building a simple Servlet 3.0 + JPA 2.0 web application. JPA 2.0 + Eclipselink was used for the database connectivity and Servlet 3.0 was used for displaying the results to the user. The sample demonstrated how the two technologies can be mixed to create a simple web application. But Servlets are meant for server-side processing rather than displaying the results to end user. JavaServer Faces 2 (another new specification in Java EE 6) is designed to fulfill that purpose.

This Tip Of The Day (TOTD) shows how to enhance the application created in TOTD #93 and use JSF 2 for displaying the results.

1. Right-click on the project, select "Properties", select "Frameworks", click on "Add ..." as shown below:
   
   
   
   Select "JavaServer Faces" and click on "OK". The following configuration screen is shown:
   
   
   
   Click on "OK" to complete the dialog. This generates a whole bunch of files (7 to be accurate) in your project. Most of these files are leftover from previous version of NetBeans and will be cleaned up. For example, "faces-config.xml" is now optional and "forwardToJSF.jsp" is redundant.
2. Anyway, lets add a POJO class that will be our managed bean. Right-click on "server" package and select "New", "Java Class ...", give the name as "StateList". Change the class such that it looks like:
   
   

   package server; import java.util.List; import javax.faces.bean.ManagedBean; import javax.persistence.EntityManagerFactory; import javax.persistence.PersistenceUnit; import states.States; /**  * @author arungupta  */ @ManagedBean public class StateList {     @PersistenceUnit     EntityManagerFactory emf;     public List<States> getStates() {         return emf.createEntityManager().createNamedQuery("States.findAll").getResultList();     } }

   
   Here are the main characterisitcs of this class:
   
1. This is a POJO class with @ManagedBean annotation. This annotation makes this class a managed bean that can be used in the JSF pages. As no other annotations or parameters are specified, this is a request-scoped managed bean with the name "stateList" and lazily initialized. More details about this annotation are available in the javadocs.
2. The persistence unit created in TOTD #93 is injected using @PersistenceUnit annotation.
3. The POJO has one getter method that queries the database and return the list of all the states.
   
3. In the generated file "template-client.xhtml", change the "head" template to:
   
   

   Show States

   
   and "body" template to:
   
   

   <h:dataTable var="state" value="#{stateList.states}" border="1">                     <h:column><h:outputText value="#{state.abbrev}"/></h:column>                     <h:column><h:outputText value="#{state.name}"/></h:column>                 </h:dataTable>


This uses the standard JSF "dataTable", "column", and "outputText" tags and uses the value expression to fetch the values from the managed bean.

Posted by Arun Gupta in General  |  Comments[3]