JSF 2.0 hello world example-白红宇

JSF 2.0 hello world example

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发布时间：2019-06-18

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In this tutorial, we will show you how to develop a JavaServer Faces (JSF) 2.0 hello world example, shows list of JSF 2.0 dependencies, basic annotations and configurations.

Project Environment

This JSF 2.0 example is built with following tools and technologies

JSF 2.1.7

Maven 3

Eclipse 3.6

JDK 1.6

Tomcat 6.0.26

First, review the final project structure, in case you are confused about where should create the corresponding files or folder later.

1. JSF 2.0 Dependencies

Maven central repository has the JSF version up to 1.2 only, to get the JSF 2.0, you may need to download from Java.net repository.

The maven central repository is updated JSF library to 2.1.7. The previous Java.net repository is no longer required.

For Java EE Application Server like Glassfish

In most Java EE application servers, it has build-in support for JSF 2.0, so you need to download the single JSF API for development purpose.

...
      
         
      
       javax.faces
          
      
       jsf-api
          
      
       2.0
          
      
       provided
        
     
    
      
         
      
       java.net.m2
          
      
       java.net m2 repo
          
      
       http://download.java.net/maven/2
        
     
    ...

For simple servlet container like Tomcat

This is a bit troublesome, you need to download following dependencies.

File : `pom.xml`


        
     
      4.0.0
         
     
      com.mkyong.common
         
     
      JavaServerFaces
         
     
      war
         
     
      1.0-SNAPSHOT
         
     
      JavaServerFaces Maven Webapp
         
     
      http://maven.apache.org
         
             
                  
       
        com.sun.faces
                   
       
        jsf-api
                   
       
        2.1.7
               
              
                  
       
        com.sun.faces
                   
       
        jsf-impl
                   
       
        2.1.7
               
              
                  
       
        javax.servlet
                   
       
        jstl
                   
       
        1.2
               
              
                  
       
        javax.servlet
                   
       
        servlet-api
                   
       
        2.5
               
              
                  
       
        javax.servlet.jsp
                   
       
        jsp-api
                   
       
        2.1
               
                      
              
                  
       
        com.sun.el
                   
       
        el-ri
                   
       
        1.0
               
          
         
             
      
       JavaServerFaces
              
                  
                       
        
         org.apache.maven.plugins
                        
        
         maven-compiler-plugin
                        
        
         2.3.1
                        
                            
         1.6                    
         
          1.6

Warning
The el-ri.jar is an arguable dependency in the Tomcat servlet container, even it’s not stated in the release note, but you need this library to solve the “JSP version of the container is older than 2.1…” error message.

Updated – 21-10-2010
This “el-ri.jar” is too old, it’s recommended to use the latest “el-impl-2.2.jar”, from Java.net


          
     
      org.glassfish.web
           
     
      el-impl
           
     
      2.2

Updated – 25-07-2012
This el-ri.jar dependency is no longer required in Tomcat 7.

2. JSF 2.0 Managed Bean

A Java bean or JSF managed bean, with a name property to store user data. In JSF, managed bean means this Java class or bean can be accessed from a JSF page.

In JSF 2.0, use @ManagedBean annotation to indicate this is a managed bean.

HelloBean.java

package com.mkyong.common;import javax.faces.bean.ManagedBean;import javax.faces.bean.SessionScoped;import java.io.Serializable;@ManagedBean@SessionScopedpublic class HelloBean implements Serializable {    private static final long serialVersionUID = 1L;        private String name;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }}

Note
In JSF 1.x, you had to declare beans in the faces-config.xml, but this is no longer required in JSF 2.0.

3. JSF 2.0 Pages

In JSF 2.0, it’s recommended to create a JSF page in XHTML file format, a file with a .xhtml extension.

See following two JSF 2.0 pages :

Note
To use the JSF 2.0 components or features, just declared the JSF namespace at the top of the page.

File : `hello.xhtml` – Renders a JSF text box and link it with the “`helloBean`” (JSF managed bean), “`name`” property, and also a button to display the “`welcome.xhtml`” page when it’s clicked.


            
                
        
            
     JSF 2.0 Hello World Example - hello.xhtml

Note
In JSF 1.x, you had to declare the “navigation rule” in “faces-config.xml“, to tell which page to display when the button is clicked. In JSF 2.0, you can put the page name directly in the button’s “action” attribute. For simple navigation, it’s more than enough, but, for complex navigation, you are still advised to use the “navigation rule” in “faces-config.xml“.

File : `welcome.xhtml` – Display the submitted text box value.


            
                
        
            
     JSF 2.0 Hello World Example - welcome.xhtml
        
     Welcome #{helloBean.name}

The #{…} indicate this is a JSF expression language, in this case, #{helloBean.name}, when the page is submitted, JSF will find the “helloBean” and set the submitted textbox value via the setName() method. When welcome.xhtml page is display, JSF will find the same session “helloBean” again and display the name property value via the getName() method.

4. JSF 2.0 Serlvet Configuration

Just like any other standard web frameworks, you are required to configure JSF stuffs in web.xml file.

File : `web.xml`


    
        
     
      JavaServerFaces
         
         
             
      
       javax.faces.PROJECT_STAGE
              
      
       Development
          
         
         
             
      
       faces/hello.xhtml
          
         
         
             
      
       Faces Servlet
              
      
       javax.faces.webapp.FacesServlet
              
      
       1
          
         
         
             
      
       Faces Servlet
              
      
       /faces/*
          
         
             
      
       Faces Servlet
              
      
       *.jsf
          
         
             
      
       Faces Servlet
              
      
       *.faces
          
         
             
      
       Faces Servlet
              
      
       *.xhtml

Define a “javax.faces.webapp.FacesServlet” mapping, and map to those well-known JSF file extensions (/faces/*, *.jsf, *.xhtml,*.faces).

In this case, the below 4 URLs are pointing to the same hello.xhtml.

http://localhost:8080/JavaServerFaces/hello.jsf    http://localhost:8080/JavaServerFaces/hello.faces    http://localhost:8080/JavaServerFaces/hello.xhtml    http://localhost:8080/JavaServerFaces/faces/hello.jsf

In JSF 2.0 development, it’s recommended to set the “javax.faces.PROJECT_STAGE” to “Development“, it will provide many useful debugging information to let you track the bugs easily. For deployment, just change it to “Production“, you just do not want your customer to look at this annoying debugging information :).