JSF in Java: A Beginner's Guide
Java Server Faces (JSF) is a server-side Java framework for web development. It provides a well-defined programming model and consists of rich API and tag libraries. JSF simplifies the UI construction by reusable UI components. JSF is designed based on the Model View Controller pattern (MVC) which segregates the presentation, controller and the business logic.
In this blogpost, we will learn the basics of JSF, its features, advantages and how to create a simple JSF application using NetBeans IDE.
What is JSF?
JSF stands for Java Server Faces. It is a UI component based and event driven MVC web application framework which simplifies the UI construction by reusable UI components. JSF specification provides a set of standard UI components which are reusable and extendable.
JSF also provides server-side validation, data conversion, defining page navigation, supports for internationalization, accessibility etc. The JSF Tag libraries are used to add components on the web pages and connect components with objects on the server. It also contains tag handlers that implements the component tag.
The latest version of JSF is 2.3 which was released in 2017. It includes major features such as bean validation for complete classes, push communication using enhanced integration with CDI (Contexts and Dependency Injection).
Why use JSF?
JSF has many benefits for web developers, such as:
- It provides clean and clear separation between behavior and presentation of web application. You can write business logic and user interface separately.
- It is based on the Servlet API, which enables various application use cases, such as using different presentation technologies, creating your own custom components directly from the component classes.
- It includes Facelets technology, which is the preferred presentation technology for building JSF based web applications. Facelets provides templating, composite components, HTML5 friendly markup etc.
- It supports Ajax (Asynchronous JavaScript and XML) which allows partial rendering of web pages without reloading the whole page.
- It has a large and active community of developers and vendors who provide support, tools and extensions for JSF.
How to create a simple JSF application?
To create a simple JSF application, you need the following prerequisites:
- Java 7 or higher version
- NetBeans IDE 8.2 or higher version
- JSF 2.2 Library (automatically installed with NetBeans IDE)
Follow these steps to create a simple JSF application:
1. Open NetBeans IDE and select File -> New Project.
2. Choose Java Web category and Web Application project type. Click Next.
3. Enter a project name (e.g. HelloJSF) and a location. Click Next.
4. Select JavaServer Faces as the framework and GlassFish Server as the server. Click Next.
5. Select Facelets as the configuration option and click Finish.
You have created a simple JSF application with a default index.xhtml page.
6. Open index.xhtml file from the Project window under Web Pages folder.
7. Replace the content of <h:body> tag with the following code:
<h:form><h:outputLabel value="Enter your name:"/><h:inputText id="name" value="#{helloBean.name}"/><h:commandButton value="Say Hello" action="#{helloBean.sayHello}"/></h:form>
This code adds a form with an input text field, a label and a button on the web page. The input text field is bound to a property called name in a managed bean called helloBean. The button invokes a method called sayHello in the same bean.
8. Right-click on the project node and select New -> Other.
9. Choose JavaServer Faces category and Managed Bean file type. Click Next.
10. Enter helloBean as the class name and choose Session as the scope. Click Finish.
You have created a managed bean class called helloBean with session scope.
11. Open helloBean.java file from the Project window under Source Packages folder.
12. Add a private String field called name with getter and setter methods.
13. Add a public String method called sayHello that returns "Hello " + name + "!".
14. Save the file.
The code of helloBean.java should look like this:
package com.example;import javax.faces.bean.ManagedBean;import javax.faces.bean.SessionScoped;@ManagedBean@SessionScopedpublic class helloBean {private String name;public String getName() {return name;}public void setName(String name) {this.name = name;}public String sayHello() {return "Hello " + name + "!";}}
This code defines a managed bean class with an annotation @ManagedBean and a scope annotation @SessionScoped. It also defines a name property and a sayHello method.
15. Right-click on the project node and select Run.
You have deployed and run the JSF application on the GlassFish server.
16. Open a web browser and enter the URL http://localhost:8080/HelloJSF/.
You should see a web page with a form to enter your name and a button to say hello.
17. Enter your name (e.g. John) and click the button.
You should see a message "Hello John!" on the web page.
Congratulations! You have created a simple JSF application using NetBeans IDE.
Conclusion
In this blogpost, we have learned the basics of JSF, its features, advantages and how to create a simple JSF application using NetBeans IDE. JSF is a powerful and popular Java framework for web development that provides a component-centric approach to developing Java Web user interfaces.