JSF: JavaServer Faces

Vinay Kumar

JSF IntroductionPage NavigationManaged BeansExpression LanguageProperties File

Event HandlingHTML LibraryValidationJDBC in JSFData Tables

Ajax-4-JSFBasic component tagsAdvanced custom tagsCustom components

Different views of JSFComparing JSF to standard servlet/JSP

technologyComparing JSF to Apache Struts

A set of Web-based GUI controls and associated handlers?– JSF provides many prebuilt HTML-oriented GUI controls, along with code to handle their events.

A device-independent GUI control framework?– JSF can be used to generate graphics in formats other than HTML, using protocols other than HTTP.

A better Struts?– Like Apache Struts, JSF can be viewed as an MVC framework forbuilding HTML forms, validating their values, invoking businesslogic, and displaying results.

• Custom GUI controls– JSF provides a set of APIs and associated custom tags to create HTML forms that have complex interfaces

• Event handling– JSF makes it easy to designate Java code that is invoked when forms are submitted. The code can respond to particular buttons, changes in particular values, certain user selections, and so on.

• Managed beans– In JSP, you can use property="*" with jsp:setProperty to automatically populate a bean based on request parameters. JSF extends this capability and adds in several utilities, all of which serve to greatly simplify request param processing.

• Expression Language– JSF provides a concise and powerful language for accessing bean properties and collection elements

• Bigger learning curve– To use MVC with the standard RequestDispatcher, you need to be comfortable with the standard JSP and servlet APIs. To use MVC with JSF, you have to be comfortable with the standard JSP and servlet APIs and a large and elaborate framework that is almost equal in size to the core system. This drawback is especially significant with smaller projects, near-term deadlines, and less experienced developers; you could spend as much time learning JSF as building your actual system.

• Worse documentation– Compared to the standard servlet and JSP APIs, JSF has fewer online resources, and many first-time users find the online JSF documentation confusing and poorly organized. MyFaces is particularly bad.

Static Navigation

• When form submitted– A static page is displayed

• Static result– No business logic, beans, or Java code of any sort– The return path is specified in the button itself.

• Main points– Format of original form– Use of navigation-rule in faces-config.xml

• Input form has following format:<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %><%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %><f:view>HTML markup<h:form>HTML markup and h:blah tags</h:form>HTML markup</f:view>

• faces-config.xml specifies navigation rules:<?xml version='1.0' encoding='UTF-8'?><!DOCTYPE faces-config PUBLIC …><faces-config><navigation-rule><from-view-id>/blah.jsp</from-view-id><navigation-case><from-outcome>some string</from-outcome><to-view-id>/WEB-INF/results/something.jsp</to-view-id></navigation-case></navigation-rule></faces-config>

The h:form element– ACTION is automatically self (current URL)– METHOD is automatically POST

• Elements inside h:form– Use special tags to represent input elements• h:inputText corresponds to <INPUT TYPE="TEXT">• h:inputSecret corresponds to <INPUT TYPE="PASSWORD">• h:commandButton corresponds to <INPUT TYPE="SUBMIT">

– In later sections, we will see that input elements will be associatedwith bean properties– For static navigation, specify simple string as action of h:commandButton

• String must match navigation rule from faces-config.xml

register.jsp<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %><%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %><f:view><!DOCTYPE …><HTML><HEAD>…</HEAD><BODY><CENTER><TABLE BORDER=5><TR><TH CLASS="TITLE">New Account Registration</TH></TR></TABLE><P><h:form>Email address: <h:inputText/><BR>Password: <h:inputSecret/><BR><h:commandButton value="Sign Me Up!" action="register"/></h:form></CENTER></BODY></HTML></f:view>

Result – resigter.jsp

• General format<?xml version='1.0' encoding='UTF-8'?><!DOCTYPE faces-config PUBLIC …><faces-config>…</faces-config>

• Specifying the navigation rules<?xml version='1.0' encoding='UTF-8'?><!DOCTYPE faces-config PUBLIC …><faces-config><navigation-rule><from-view-id>/register.jsp</from-view-id><navigation-case><from-outcome>register</from-outcome><to-view-id>/WEB-INF/results/result.jsp</to-view-id></navigation-case></navigation-rule></faces-config>

RequestDispatcher.forward used– So page can/should be in WEB-INF

• Example code:– …/WEB-INF/results/result.jsp

<!DOCTYPE …><HTML><HEAD>…</HEAD><BODY><CENTER><TABLE BORDER=5><TR><TH CLASS="TITLE">Success</TH></TR></TABLE><H2>You have registered successfully.</H2></CENTER></BODY></HTML>

Note that the URL is unchanged

Filename/URL correspondence– Actual files are of the form blah.jsp– URLs used are of the form blah.faces– You must prevent clients from directly accessing JSPpages

• Since they would give erroneous results• Strategies

– You cannot put input-form JSP pages in WEB-INF• Because URL must correspond directly to file location

– So, use filter in web.xml. But:• You have to know the extension (.faces)• Assumes no non-JSF .jsp pages

• This is a major drawback to JSF design

FacesRedirectFilter

public class FacesRedirectFilter implements Filter {private final static String EXTENSION = "faces";public void doFilter(ServletRequest req,ServletResponse res,FilterChain chain)throws ServletException, IOException {HttpServletRequest request = (HttpServletRequest)req;HttpServletResponse response = (HttpServletResponse)res;String uri = request.getRequestURI();if (uri.endsWith(".jsp")) {int length = uri.length();String newAddress =uri.substring(0, length-3) + EXTENSION;response.sendRedirect(newAddress);} else { // Address ended in "/"response.sendRedirect("index.faces");}}

<filter><filter-name>faces-redirect-filter</filter-name><filter-class>coreservlets.FacesRedirectFilter</filter-class></filter><filter-mapping><filter-name>faces-redirect-filter</filter-name><url-pattern>*.jsp</url-pattern></filter-mapping>

Dynamic Navigation

• A form is displayed– Form uses f:view and h:form

• The form is submitted to itself– Original URL and ACTION URL are http://…/blah.faces

• A bean is instantiated– Listed in the managed-bean section of faces-config.xml

• The action controller method is invoked– Listed in the action attribute of h:commandButton

• The action method returns a condition– A string that matches from-outcome in the navigation rules in

faces-config.xml• A results page is displayed

– The page is specified by to-view-id in the navigation rules in faces-config.xml

1) Create a beanA) Properties for form dataB) Action controller methodC) Placeholders for results data

2) Create an input formA) Input fields refer to bean propertiesB) Button specifies action controller method that will return

condition3) Edit faces-config.xml

A) Declare the beanB) Specify navigation rules

4) Create results pages– Output form data and results data with h:outputText

5) Prevent direct access to JSP pages– Use a filter that redirects blah.jsp to blah.faces

• Collects info to see if user qualifies for health plan

• When form submitted, one of two possible

results will be displayed– User is accepted into health plan– User is rejected from health plan

• Main points– Specifying an action controller in the form– Creating an action controller method in the bean– Using faces-config.xml to

• Declare bean• Map return conditions to output pages

• Specify the controller with #{beanName.methodName}<h:commandButtonvalue="Sign Me Up!"action="#{healthPlanController.signup}"/>

• Controller method returns strings corresponding to conditions– If null is returned, the form is redisplayed– Unlike with Struts, the controller need not extend a special class

• Use faces-config.xml to declare the controller as follows<faces-config><managed-bean><managed-bean-name>controller name</managed-bean-name><managed-bean-class>controller class</managed-bean-class><managed-bean-scope>request</managed-bean-scope></managed-bean></faces-config>

• Add multiple navigation-rule entries to faces-config.xml– One for each possible string returned by the controller– If no string matches, the form is redisplayed

(A) Properties for form data– Postponed until next session

(B) Action controller methodpublic class HealthPlanController {public String signup() {if (Math.random() < 0.2) {return("accepted");} else {return("rejected");}}}

(C) Placeholders for results data– Postponed until next session

• Same general syntax as in previous example– Except for action of commandButton

<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %><%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %><f:view>…<h:form>First name: <h:inputText/><BR>Last name: <h:inputText/><BR>...<h:commandButtonvalue="Sign Me Up!"action="#{healthPlanController.signup}"/></h:form>…</f:view>

(A) Declaring the bean…<faces-config><managed-bean><managed-bean-name>healthPlanController</managed-bean-name><managed-bean-class>coreservlets.HealthPlanController</managed-bean-class><managed-bean-scope>request</managed-bean-scope></managed-bean>…</faces-config>

(B) Specifying navigation rules– Outcomes should match return values of controller<faces-config>… (bean definitionsfrom previous page)<navigation-rule><from-view-id>/signup.jsp</from-view-id><navigation-case><from-outcome>accepted</from-outcome><to-view-id>/WEB-INF/results/accepted.jsp</to-view-id></navigation-case><navigation-case><from-outcome>rejected</from-outcome><to-view-id>/WEB-INF/results/rejected.jsp</to-view-id></navigation-case></navigation-rule></faces-config>

• …/WEB-INF/results/accepted.jsp<!DOCTYPE …><HTML><HEAD>…</HEAD><BODY><CENTER><TABLE BORDER=5><TR><TH CLASS="TITLE">Accepted!</TH></TR></TABLE><H2>You are accepted into our health plan.</H2>Congratulations.</CENTER></BODY></HTML>

…/WEB-INF/results/accepted.jsp<!DOCTYPE …><HTML><HEAD>…</HEAD><BODY><CENTER><TABLE BORDER=5><TR><TH CLASS="TITLE">Accepted!</TH></TR></TABLE><H2>You are accepted into our health plan.</H2>Congratulations.</CENTER></BODY></HTML>

…/WEB-INF/results/rejected.jsp<!DOCTYPE …><HTML><HEAD>…</HEAD><BODY><CENTER><TABLE BORDER=5><TR><TH CLASS="TITLE">Rejected!</TH></TR></TABLE><H2>You are rejected from our health plan.</H2>Get lost.</CENTER></BODY></HTML>

• Use filter that captures url-pattern *.jsp– No changes from previous example

• Wildcards in navigation rule– * for from-view-id matches any starting page

<navigation-rule><from-view-id>*</from-view-id><navigation-case><from-outcome>success</from-outcome><to-view-id>/WEB-INF/results/success.jsp</to-view-id></navigation-case></navigation-rule>

• Getting the request and response objectsHttpServletRequest request =(HttpServletRequest)context.getRequest();HttpServletResponse response =(HttpServletResponse)context.getResponse();

• In some environments, you cast results of getRequest and getResponse to values other than HttpServletRequest and HttpServletResponseE.g., in a portlet environment, you might cast result toPortletRequest and PortletResponse

• If you have several different addresses inyour app, it is OK to alternate

<managed-bean>Stuff for bean1</managed-bean><navigation-rule>Rules for address that uses bean1</navigation-rule><managed-bean>Stuff for bean2</managed-bean><navigation-rule>Rules for address that uses bean2</navigation-rule>

– Of course, it is also OK to put all bean defs at the top,followed by all navigation rules.

• Using beans to represent requestparameters• Declaring beans in faces-config.xml• Referring to beans in input forms• Outputting bean properties

1) Create a beanA) Properties for form dataB) Action controller methodC) Placeholders for results data

2) Create an input formA) Input fields refer to bean propertiesB) Button specifies action controller method that will return

condition3) Edit faces-config.xml

A) Declare the beanB) Specify navigation rules

4) Create results pages– Output form data and results data with h:outputText

5) Prevent direct access to JSP pages– Use a filter that redirects blah.jsp to blah.faces

• When form submitted, three possible results– Error message re illegal email address– Error message re illegal password– Success

• New features– Action controller obtains request data from within bean– Output pages access bean properties

• Main points– Defining a bean with properties for the form data– Declaring beans in faces-config.xml– Outputting bean properties

(1A) Form datapublic class RegistrationBean implements Serializable {private String email = "user@host";private String password = "";public String getEmail() {return(email);}public void setEmail(String email) {this.email = email;}public String getPassword() {return(password);}public void setPassword(String password) {this.password = password;}

(1B) Action controller methodpublic String register() {if ((email == null) ||(email.trim().length() < 3) ||(email.indexOf("@") == -1)) {suggestion = SuggestionUtils.getSuggestionBean();return("bad-address");} else if ((password == null) ||(password.trim().length() < 6)) {suggestion = SuggestionUtils.getSuggestionBean();return("bad-password");} else {return("success");}}

(1C) Placeholder for storing results– Note that action controller method called business logic and placed the result in this placeholder

private SuggestionBean suggestion;public SuggestionBean getSuggestion() {return(suggestion);}

Result returned by business logicpackage coreservlets;import java.io.*;public class SuggestionBean implements Serializable {private String email;private String password;public SuggestionBean(String email, String password) {this.email = email;this.password = password;}public String getEmail() {return(email);}public String getPassword() {return(password);}}

• Business logicpublic class SuggestionUtils {private static String[] suggestedAddresses ={ "[email protected]","[email protected]",“[email protected]",“[email protected]" };private static String chars ="abcdefghijklmnopqrstuvwxyz0123456789#@$%^&*?!";public static SuggestionBean getSuggestionBean() {String address = randomString(suggestedAddresses);String password = randomString(chars, 8);return(new SuggestionBean(address, password));}...}

• Similar to previous example, except– h:inputBlah tags given a value attribute identifying the

corresponding bean property• Example code

<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %><%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %><f:view>…<h:form>Email address:<h:inputText value="#{registrationBean.email}"/><BR>Password:<h:inputSecret value="#{registrationBean.password}"/><BR><h:commandButton value="Sign Me Up!"action="#{registrationBean.register}"/></h:form>…</f:view>

The user@host value comes from the bean

(A) Declare bean…<faces-config><managed-bean><managed-bean-name>registrationBean</managed-bean-name><managed-bean-class>coreservlets.RegistrationBean</managed-bean-class><managed-bean-scope>request</managed-bean-scope></managed-bean>…</faces-config>

• (B) Define navigation rules…<faces-config>…<navigation-rule><from-view-id>/register.jsp</from-view-id><navigation-case><from-outcome>bad-address</from-outcome><to-view-id>/WEB-INF/results/bad-address.jsp</to-view-id></navigation-case><navigation-case><from-outcome>bad-password</from-outcome><to-view-id>/WEB-INF/results/bad-password.jsp</to-view-id></navigation-case><navigation-case><from-outcome>success</from-outcome><to-view-id>/WEB-INF/results/success.jsp</to-view-id></navigation-case></navigation-rule></faces-config>

• …/jsf-beans/WEB-INF/results/bad-address.jsp<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %><%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %><f:view><!DOCTYPE …><HTML>…<TABLE BORDER=5><TR><TH CLASS="TITLE">Illegal Email Address</TH></TR></TABLE><P>The address"<h:outputText value="#{registrationBean.email}"/>"is not of the form username@hostname (e.g.,<h:outputTextvalue="#{registrationBean.suggestion.email}"/>).<P>Please <A HREF="register.faces">try again</A>.…</HTML></f:view>

Input

Output

• Use filter that captures url-pattern *.jsp– No changes from previous example

Important• Shorthand notation for bean properties.

– To reference the companyName property (i.e., result of the getCompanyName method) of a scoped variable (i.e. object stored in request, session, or application scope) or managed bean named company, you use #{company.companyName}. To reference the firstName property of the president property of a scoped variable or managed bean named company, you use #{company.president.firstName}.

• Simple access to collection elements.– To reference an element of an array, List, or Map, you use #{variable[indexOrKey]}. Provided that the index or key is in a form that is legal for Java variable names, the dot notation for beans is interchangeable with the bracket notation for collections.

Less Important• Succinct access to request parameters, cookies, and other

request data.– To access the standard types of request data, you can use one of several predefined implicit objects.

• A small but useful set of simple operators.– To manipulate objects within EL expressions, you can use any of several arithmetic, relational, logical, or empty-testing operators.

• Conditional output.– To choose among output options, you do not have to resort to Java scripting elements. Instead, you can use #{test ? option1 : option2}.

• Automatic type conversion.– The expression language removes the need for most typecasts and for much of the code that parses strings as numbers.

• Empty values instead of error messages.– In most cases, missing values or

To enforce EL-only with no scripting, use scripting-invalid in web.xml– Still permits both the JSF EL and the JSP 2.0 EL<?xml version="1.0" encoding="ISO-8859-1"?><web-app xmlns="http://java.sun.com/xml/ns/j2ee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-app_2_4.xsd"version="2.4"><jsp-property-group><url-pattern>*.jsp</url-pattern><scripting-invalid>true</scripting-invalid></jsp-property-group></web-app>

import java.util.*;public class TestBean {private Date creationTime = new Date();private String greeting = "Hello";public Date getCreationTime() {return(creationTime);}public String getGreeting() {return(greeting);}public double getRandomNumber() {return(Math.random());}}

<?xml version='1.0' encoding='UTF-8'?><!DOCTYPE ...><faces-config><managed-bean><managed-bean-name>testBean</managed-bean-name><managed-bean-class>coreservlets.TestBean</managed-bean-class><managed-bean-scope>request</managed-bean-scope></managed-bean>...</faces-config>

<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %><%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %><f:view>...<BODY><TABLE BORDER=5 ALIGN="CENTER"><TR><TH CLASS="TITLE">Accessing Bean Properties</TH></TR></TABLE><UL><LI>Creation time:<h:outputText value="#{testBean.creationTime}"/><LI>Greeting:<h:outputText value="#{testBean.greeting}"/><LI>Random number:<h:outputText value="#{testBean.randomNumber}"/></UL></BODY></HTML></f:view>

public class NameBean {private String firstName = "Missing first name";private String lastName = "Missing last name";public NameBean() {}public NameBean(String firstName, String lastName) {setFirstName(firstName);setLastName(lastName);}public String getFirstName() {return(firstName);}public void setFirstName(String newFirstName) {firstName = newFirstName;}...}

public class CompanyBean {private String companyName;private String business;public CompanyBean(String companyName,String business) {setCompanyName(companyName);setBusiness(business);}public String getCompanyName() { return(companyName); }public void setCompanyName(String newCompanyName) {companyName = newCompanyName;}...}

public class EmployeeBean {private NameBean name;private CompanyBean company;public EmployeeBean(NameBean name, CompanyBean company) {setName(name);setCompany(company);}public EmployeeBean() {this(new NameBean("Marty", "Hall"),new CompanyBean("coreservlets.com","J2EE Training and Consulting"));}public NameBean getName() { return(name); }public void setName(NameBean newName) {name = newName;}...}

<faces-config>...<managed-bean><managed-bean-name>employee</managed-bean-name><managed-bean-class>coreservlets.EmployeeBean</managed-bean-class><managed-bean-scope>request</managed-bean-scope></managed-bean>...</faces-config>

<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %><%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %><f:view>...<BODY><TABLE BORDER=5 ALIGN="CENTER"><TR><TH CLASS="TITLE">Using Nested Bean Properties</TH></TR></TABLE><UL><LI>Employee's first name:<h:outputText value="#{employee.name.firstName}"/><LI>Employee's last name:<h:outputText value="#{employee.name.lastName}"/><LI>Name of employee's company:<h:outputText value="#{employee.company.companyName}"/><LI>Business area of employee's company:<h:outputText value="#{employee.company.business}"/></UL></BODY></HTML></f:view>

• Loading properties files• Simple messages• Parameterized messages• Internationalized messages

1. Create a .properties file• Contains simple keyName=value pairs• Must be deployed to WEB-INF/classes• In Eclipse, this means you put it in "src" folder

2. Load file with f:loadBundle– basename gives base file name– var gives scoped variable (Map) that will hold results

• Relative to WEB-INF/classes, .properties assumed• E.g., for WEB-INF/classes/messages.properties<f:loadBundle basename="messages" var="msgs"/>• E.g., for WEB-INF/classes/package1/test.properties<f:loadBundle basename="package1.test" var="msgs"/>

3. Output messages using normal EL– #{msgs.keyName}

1. Create a .properties file in/under WEB-INF/classes– Values contain {0}, {1}, {2}, etc.– E.g., someName=blah {0} blah {1}– Warning: MyFaces bug prevents single quotes in values

2. Load file with f:loadBundle as before– basename gives base file name– var gives scoped variable (Map) that will hold results

3. Output messages using h:outputFormat– value gives base message– nested f:param gives substitution values– E.g.:

<h:outputFormat value="#{msgs.someName}"><f:param value="value for 0th entry"/><f:param value="value for 1st entry"/></h:outputFormat>

1. Create multiple similarly named .properties files– blah.properties, blah_es.properties,

blah_es_mx.properties2. Supply locale argument to f:view<f:view locale="#{facesContext.externalContext.request.locale}">– Determines locale from browser language

settings– Can also set the Locale based on user input

locale="#{settings.selectedLocale}"

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JSF: JavaServer Faces