SETTING UP JSF

-
If you have knowledge on java web applications it is very easy to set up Java server faces application.If you have  normal web application follow the below steps to convert it into a jsf app.
  1. An entry in the web application's web.xml to process all the requests by JSF controller servlet called Faces Servlet and a certain URL pattern is specified.

   
         <!-- Faces Servlet -->
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup> 1 </load-on-startup>
    </servlet>


    <!-- Faces Servlet Mapping -->
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.faces</url-pattern>
    </servlet-mapping>


      2 . A JSF configuration file faces-config.xml, which allows for configuration of all elements of JSF     application.It is usually located in the web application's WEB-INF/directory.We need to keep an entry int the web.xml.We will discuss the contents later.
    <context-param>
        <param-name>javax.faces.CONFIG_FILES</param-name>
        <param-value>/WEB-INF/faces-config.xml</param-value>
    </context-param>



     3 . Keep the below jar files in WEB-INF/lib. 
  • Actual JSF libraries : jsf-api.jar and jsf-impl.jar.
  • Additional dependencies : commons-beanutils.jar,commons-collections.jar,commons-digester.jar and commons-logging.jar
  • JSTL jar files : jstl.jar and standard.jar.


With above steps our web application is properly configured for JSF.
Next step is to develop a view using JSF.
  1. Create a page HelloJSF.jsp in the web application.
  2. Add the below lines in the jsp page to make it JSF compliance.These are core and html tag libraries from sun's reference implementation.
<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %>
<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %>


     3. In the body of the JSP,you must add a tag.This is the base UI component .All the jsf tags must be inside this view tag.
Following are the sample files of web.xml and a jsp page ::


Web.xml
<?xml version="1.0"?>
<!DOCTYPE web-app PUBLIC
  "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
  "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>

    <context-param>
        <param-name>javax.faces.CONFIG_FILES</param-name>
        <param-value>/WEB-INF/faces-config.xml</param-value>
    </context-param>

    <!-- Faces Servlet -->
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup> 1 </load-on-startup>
    </servlet>


    <!-- Faces Servlet Mapping -->
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.faces</url-pattern>
    </servlet-mapping>
</web-app>



   
JSP Page


<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %>
<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %>
<html >
    <head>
        <title>My First JSF Application</title>
              
    </head>
    <body>
                  <f:view>
                       <h:outputText value="This is MY JSF.."/>                                            
                 </f:view>
       
    </body>
</html>
   


 Once the JSP is created then we need to deploy that application in server and enter the below URL in the browser.
http://localhost:8080//HelloJSF.faces
 Note ::  We need to give the name as HelloJSF.faces eventhogh its exentsion is JSP to wake up the FacesServlet.The servlet container uses the servlet mapping rule to activate the JSF servlet, which strips off the faces suffix and loads the HelloJSF.jsp page.   


 This is all about a sample JSF application .we will discuss in depth in the later posts.







Comments

Post a Comment

Popular posts from this blog

What's New in JAVA 8

-
Finally Java 8 released under oracle leadership with many features and enhancements. Though some of the popular JSR's like JSR 294 (Jigsaw) are deferred again to next release, Java 8 still be the largest ever upgrade to java after it was introduced in 1996.  Lets see one of those improvements.  Performance improvement of java.util.HashMap under high hash-collision conditions : Just to give a little background : HashMap is used to store key-value pairs in no.of buckets technically 'Entry' objects . Entry is an inner class of HashMap. Please click  here to see the source code in java 7. Each bucket has a unique number called hash code. When you try to put a key-value pair into the map, the hashmap will look at the hash code of the key, and store the pair in the bucket of which the identifier is the hash code of the key. Let's say if hash code of two keys are same then hash-collision occurs. Till now (prior to Java 8), hash collision is addressed by creati
Read more

Singleton Design Pattern

-
We need to create a class which can have only one instance at any time. Solution 1: public class MySingleton { private static MySingleton singleton= new MySingleton(); private MySingleton(){ System.out.println( "Object Created" ); } public static MySingleton getMySingleton(){ return singleton; } } Let's create the object when we need it, not at the time of loading the class. Solution 2(with Lazy loading): public class MySingleton { // Line : 1 private static MySingleton singleton=null; // Line : 2 private MySingleton(){ System.out.println( "Object Created" ); } // Line : 3 public static MySingleton getMySingleton(){ // Line : 4 if(singleton == null) // Line : 5 { singleton = new MySingleton();
Read more

Internals of JSF

-
Once jsf project set up properly i.e entries in the web.xml,jsf related jars in lib folder of your web app( setting up jsf project ) we have to create a faces-config.xml to make our set up into a full fledged jsf application. Creating Faces-config.xml :: In the name itself telling us that it contains all the configurations needed for all jsf pages.In fact we don't need to create the file with the same name.We can create it with any name and we have to mention same as a context parameter in the WEB.xml ( setting up jsf project ).Now its the time to jump into the detailed view.   Fallowing are the two main components that we use frequently. 1)Managed Beans It represents a Java bean that will be instantiated dynamically at the run time by JSF container.We can achive inversion of control in JSF. Ex: Class User{ private String name; private String Address; //setters and getters for both properties } Declaration in faces-config.xml   <man
Read more