Java TM. JavaServer Faces. Jaroslav Porubän 2008

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1 JavaServer Faces Jaroslav Porubän 2008

2 Web Applications Presentation-oriented Generates interactive web pages containing various types of markup language (HTML, XML, and so on) and dynamic content in response to requests Service-oriented Implements the endpoint of a web service, presentation-oriented applications are often clients of service-oriented web applications

3 Request-Response Model

4 Java Web Application Technologies Servlets JavaServer Pages JavaServer Faces

5 Servlet Used to extend the capabilities of servers that host applications accessed by means of a requestresponse programming model Regular Java class, must implement the Servlet interface Output is generated from the standard Java code

6 Servlet Example public class HelloWorldServlet extends HttpServlet { protected void service(httpservletrequest request, HttpServletResponse response) throws ServletException, IOException { response.setcontenttype("text/html; charset=utf-8"); PrintWriter out = response.getwriter(); try { out.println("<html>"); out.println("<head><title>servlet test</title></head>"); out.println("<body>"); out.println("<h1>hello on " + new Date() + "</h1>"); out.println("</body>"); out.println("</html>"); } finally { out.close(); } } }

7 JavaServer Pages (JSP) Text-based documents that execute as servlets but allow a more natural approach to creating static content Transformed into servlets by a web container JSP page with embeded Java code

8 JavaServer Pages Example <html> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"> </head> <body> </html> </body> <title>jsp test</title> <h1>hello on <%=new java.util.date()%></h1>

9 JavaServer Faces Web-tier user interface component framework for Java technology-based web applications An event-driven programming model A component model that enables third-party developers to supply additional components

10 JavaServer Faces Architecture A set of UIComponent classes for specifying the state and behavior of UI components A rendering model that defines how to render the components in various ways An event and listener model that defines how to handle component events A conversion model that defines how to register data converters onto a component A validation model that defines how to register validators onto a component

11 JSF Example <html xmlns=" xml:lang="en"> <head><title>hello</title></head> page contenttype="text/html" %> taglib uri=" prefix="h" %> taglib uri=" prefix="f" %> <body> <f:view> <h:form id="helloform" > <h2>hi. My name is Duke. I'm thinking of a number from <h:outputtext value="#{usernumberbean.minimum}"/> to <h:outputtext value="#{usernumberbean.maximum}"/>. Can you guess it?</h2> <h:inputtext id="userno" label="user Number" value="#{usernumberbean.usernumber}" convertermessage="#{errmsg.usernoconvert}"> <f:validatelongrange minimum="#{usernumberbean.minimum}" maximum="#{usernumberbean.maximum}" /> </h:inputtext> <h:commandbutton id="submit" action="success" value="submit" /> <p><h:message style="color: red" id="errors1" for="userno"/></p> </h:form> </f:view> </body> </html>

12 Managed Beans Separation of model from view Model handles application logic and data managed beans View handles presentation UI components Registered in faces-config.xml <managed-bean> <managed-bean-name>usernumberbean</managed-bean-name> <managed-bean-class> guessnumber.usernumberbean</managed-bean-class> <managed-bean-scope>session</managed-bean-scope> </managed-bean>

13 Backing Beans Managed bean associated with the UI components used in a particular page Can be bound to A component instance A component s value A converter instance A listener instance A validator instance

14 Backing Beans Example public class UserNumberBean { private Integer random = null; private Integer usernumber = null; private int min = 0; private int max = 10; public void init() { random = new Random().nextInt(max - min + 1) + min; } //... public String getresponse() { if ((usernumber!= null) && (usernumber.compareto(randomint) == 0)) { return "Yay! You got it!"; } else { return "Sorry, " + usernumber + " is incorrect."; } }

15 Bean Scopes Request Scope starts when an HTTP request is submitted and ends when the response is sent back to the client Session Scope repeated connections by the same client Application Scope persists for the entire duration of the web application, scope is shared among all requests and all sessions.

16 Navigation Model Navigation rules are defined in the configuration file faces-config.xml Determine which page to go to after the user clicks a button or a hyperlink Navigation rule defines how to get from one page to the other pages of the application can contain any number of navigation cases Navigation case defines the page to open next based on a logical outcome

17 Navigation Example <navigation-rule> <from-view-id>/greeting.jsp</from-view-id> <navigation-case> <from-outcome>success</from-outcome> <to-view-id>/response.jsp</to-view-id> </navigation-case> </navigation-rule> <navigation-rule> <from-view-id>/response.jsp</from-view-id> <navigation-case> <from-outcome>success</from-outcome> <to-view-id>/greeting.jsp</to-view-id> </navigation-case> </navigation-rule>

18 Navigation Example

19 JSF Development Roles Page author creates the user interface of a web application Component writer creates reusable components, renderers, and libraries Application developer creates the other tiers of an application Tool provider creates tools to assist page authors, component writers, and application developers JSF implementor provides runtime environment to execute JSF webapps

20 JSF Life Cycle

04/29/2004. Step by Step Guide for Building a simple JSF Application (Guess a Number) - V1.0

04/29/2004. Step by Step Guide for Building a simple JSF Application (Guess a Number) - V1.0 Step by Step Guide for Building a simple JSF Application (Guess a Number) - V1.0 1 Sang Shin sang.shin@sun.com www.javapassion.com Java Technology Evangelist Sun Microsystems, Inc. 2 Disclaimer & Acknowledgments