JSF Application that uses managed-bean and ejb

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This is a simple web-app showing how to use dependency injection in JSF managed beans using TomEE.

It contains a Local Stateless session bean CalculatorImpl which adds two numbers and returns the result. The application also contains a JSF managed beanCalculatorBean, which uses the EJB to add two numbers and display the results to the user. The EJB is injected in the managed bean using @EJB annotation.

A little note on the setup:

You could run this in the latest Apache TomEE snapshot

As for the libraries, myfaces-api and myfaces-impl are provided in tomee/lib and hence they should not be a part of the war. In maven terms, they would be with scope 'provided'

Also note that we use servlet 2.5 declaration in web.xml

 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">

And we use 2.0 version of faces-config

The complete source code is provided below but let's break down to look at some smaller snippets and see how it works.

We'll first declare the FacesServlet in the web.xml

  
    Faces Servlet

javax.faces.webapp.FacesServlet 1

FacesServlet acts as the master controller.

We'll then create the calculator.xhtml file.

        value='Enter first number'/>
        value='#{calculatorBean.x}'/>
        value='Enter second number'/>
        value='#{calculatorBean.y}'/>
        action="#{calculatorBean.add}" value="Add"/>

Notice how we've use the bean here. By default it is the simple class name of the managed bean.

When a request comes in, the bean is instantiated and placed in the appropriate scope. By default, the bean is placed in the request scope.

         value='#{calculatorBean.x}'/>

Here, getX() method of calculatorBean is invoked and the resulting value is displayed. x being a Double, we rightly should see 0.0 displayed.

When you change the value and submit the form, these entered values are bound using the setters in the bean and then the commandButton-action method is invoked.

In this case, CalculatorBean#add() is invoked.

Calculator#add() delegates the work to the ejb, gets the result, stores it and then instructs what view is to be rendered.

You're right. The return value "success" is checked up in faces-config navigation-rules and the respective page is rendered.

In our case, result.xhtml page is rendered.

The request scoped calculatorBean is available here, and we use EL to display the values.

Source

Calculator

package org.superbiz.jsf;

import javax.ejb.Remote;

@Remote
public interface Calculator {
    public double add(double x, double y);
}

CalculatorBean

package org.superbiz.jsf;

import javax.ejb.EJB;
import javax.faces.bean.ManagedBean;

@ManagedBean
public class CalculatorBean {
    @EJB
    Calculator calculator;
    private double x;
    private double y;
    private double result;

    public double getX() {
        return x;
    }

    public void setX(double x) {
        this.x = x;
    }

    public double getY() {
        return y;
    }

    public void setY(double y) {
        this.y = y;
    }

    public double getResult() {
        return result;
    }

    public void setResult(double result) {
        this.result = result;
    }

    public String add() {
        result = calculator.add(x, y);
        return "success";
    }
}

CalculatorImpl

package org.superbiz.jsf;

import javax.ejb.Stateless;

@Stateless
public class CalculatorImpl implements Calculator {

    public double add(double x, double y) {
        return x + y;
    }
}

web.xml

xml version="1.0"?>

     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">

    MyProject web.xml

Faces Servlet javax.faces.webapp.FacesServlet 1 Faces Servlet *.jsf index.jsp index.html

Calculator.xhtml

xml version="1.0" encoding="UTF-8"?>

 xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html">


 bgcolor="white">
    
        
             columns="2">
             value='Enter first number'/>
            value='#{calculatorBean.x}'/>
             value='Enter second number'/>
             value='#{calculatorBean.y}'/>
            action="#{calculatorBean.add}" value="Add"/>
            
        

Result.xhtml

xml version="1.0" encoding="UTF-8"?>

 xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html">


    
         id="mainForm">
            

 value="Result of adding #{calculatorBean.x} and #{calculatorBean.y} is #{calculatorBean.result }"/>

             action="back">
             value="Home"/>
            
        
    

faces-config.xml

xml version="1.0"?>
 xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-facesconfig_2_0.xsd"
version="2.0">


    /calculator.xhtml

success /result.xhtml /result.xhtml back /calculator.xhtml

 

APIs Used

• javax.ejb.EJB
• javax.ejb.Remote
• javax.ejb.Stateless
• javax.faces.bean.ManagedBean

Source

• Apache jsf-managedBean-and-ejb
• Github jsf-managedBean-and-ejb

svn co http://svn.apache.org/repos/asf/tomee/tomee/trunk/examples/jsf-managedBean-and-ejb
cd jsf-managedBean-and-ejb
mvn clean install

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