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Using JavaServer Faces Technology in WebPagesWeb pages (Facelets pages, in most cases) represent the presentation layer for webapplications. The process of creating web pages for a JavaServer Faces applicationincludes using component tags to add components to the page and wire them tobacking beans, validators, listeners, converters, and other server-side objects that areassociated with the page.This chapter explains how to create web pages using various types of component andcore tags. In the next chapter, you will learn about adding converters, validators, andlisteners to component tags to provide additional functionality to components.Many of the examples in this chapter are taken from Chapter 57, "Duke's BookstoreCase Study Example."The following topics are addressed here:■ Setting Up a Page■ Adding Components to a Page Using HTML Tag Library Tags■ Using Core Tags
10.1 Setting Up a PageA typical JavaServer Faces web page includes the following elements:■ A set of namespace declarations that declare the JavaServer Faces tag libraries■ Optionally, the HTML head (h:head) and body (h:body) tags■ A form tag (h:form) that represents the user input componentsTo add the JavaServer Faces components to your web page, you need to provide thepage access to the two standard tag libraries: the JavaServer Faces HTML render kittag library and the JavaServer Faces core tag library. The JavaServer Faces standardHTML tag library defines tags that represent common HTML user interfacecomponents. This library is linked to the HTML render kit athttp://docs.oracle.com/javaee/7/javaserverfaces/2.2/renderkitdocs/. The JavaServer Faces core tag library defines tags that perform core actions and areindependent of a particular render kit.For a complete list of JavaServer Faces Facelets tags and their attributes, refer to thedocumentation athttp://docs.oracle.com/javaee/7/javaserverfaces/2.2/vdldocs/facelets/.Adding Components to a Page Using HTML Tag Library Tags10-2 The Java EE 7 TutorialTo use any of the JavaServer Faces tags, you need to include appropriate directives atthe top of each page specifying the tag libraries.For Facelets applications, the XML namespace directives uniquely identify the taglibrary URI and the tag prefix.For example, when you create a Facelets XHTML page, include namespace directivesas follows:<html xmlns="http://www.w3.org/1999/xhtml"xmlns:h="http://xmlns.jcp.org/jsf/html"xmlns:f="http://xmlns.jcp.org/jsf/core">The XML namespace URI identifies the tag library location, and the prefix value isused to distinguish the tags belonging to that specific tag library. You can also useother prefixes instead of the standard h or f. However, when including the tag in thepage, you must use the prefix that you have chosen for the tag library. For example, inthe following web page, the form tag must be referenced using the h prefix because thepreceding tag library directive uses the h prefix to distinguish the tags defined in
HTML tag library:<h:form ...>The sections Adding Components to a Page Using HTML Tag Library Tags and UsingCore Tags describe how to use the component tags from the JavaServer Faces standardHTML tag library and the core tags from the JavaServer Faces core tag library.
10.2 Adding Components to a Page Using HTML Tag Library TagsThe tags defined by the JavaServer Faces standard HTML tag library represent HTMLform components and other basic HTML elements. These components display data oraccept data from the user. This data is collected as part of a form and is submitted tothe server, usually when the user clicks a button. This section explains how to use eachof the component tags shown in Table 10–1.Table 10–1 The Component TagsTag Functions Rendered As Appearanceh:column Represents a column ofdata in a data componentA column of data inan HTML tableA column in atableh:commandButton Submits a form to theapplicationAn HTML <inputtype=type> element,where the type valuecan be "submit","reset", or "image"A buttonh:commandLink Links to another page orlocation on a pageAn HTML <a href>elementA linkh:dataTable Represents a datawrapperAn HTML <table>elementA table that canbe updateddynamicallyh:form Represents an input form(inner tags of the formreceive the data that willbe submitted with theform)An HTML <form>elementNo appearanceh:graphicImage Displays an image An HTML <img>elementAn imageAdding Components to a Page Using HTML Tag Library TagsUsing JavaServer Faces Technology in Web Pages 10-3h:inputFile Allows a user to upload afileAn HTML <inputtype="file">element
A field with aBrowse... buttonh:inputHidden Allows a page author toinclude a hidden variablein a pageAn HTML <inputtype="hidden">elementNo appearanceh:inputSecret Allows a user to input astring without the actualstring appearing in thefieldAn HTML <inputtype="password">elementA field, whichdisplays a row ofcharacters insteadof the actualstring enteredh:inputText Allows a user to input astringAn HTML <inputtype="text">elementA fieldh:inputTextarea Allows a user to enter amultiline stringAn HTML<textarea> elementA multi-row fieldh:message Displays a localizedmessageAn HTML <span> tagif styles are usedA text stringh:messages Displays localizedmessagesA set of HTML<span> tags if stylesare usedA text stringh:outputFormat Displays a formattedmessagePlain text Plain texth:outputLabel Displays a nestedcomponent as a label fora specified input fieldAn HTML <label>elementPlain texth:outputLink Links to another page orlocation on a pagewithout generating anaction eventAn HTML <a>elementA linkh:outputText Displays a line of text Plain text Plain text
h:panelGrid Displays a table An HTML <table>element with <tr>and <td> elementsA tableh:panelGroup Groups a set ofcomponents under oneparentA HTML <div> or<span> elementA row in a tableh:selectBooleanCheckboxAllows a user to changethe value of a BooleanchoiceAn HTML <inputtype="checkbox">element.A check boxh:selectManyCheckbox Displays a set of checkboxes from which theuser can select multiplevaluesA set of HTML<input> elements oftype checkboxA group of checkboxesh:selectManyListbox Allows a user to selectmultiple items from a setof items, all displayed atonceAn HTML <select>elementA boxh:selectManyMenu Allows a user to selectmultiple items from a setof itemsAn HTML <select>elementA menuTable 10–1 (Cont.) The Component TagsTag Functions Rendered As AppearanceAdding Components to a Page Using HTML Tag Library Tags10-4 The Java EE 7 TutorialThe tags correspond to components in the javax.faces.component package. Thecomponents are discussed in more detail in Chapter 12, "Developing with JavaServerFaces Technology."The next section explains the important attributes that are common to mostcomponent tags. For each of the components discussed in the following sections,Writing Bean Properties explains how to write a bean property bound to a particularcomponent or its value.For reference information about the tags and their attributes, see the APIdocumentation for the Facelets tag library athttp://docs.oracle.com/javaee/7/javaserverfaces/2.2/vdldocs/facelets/.
10.2.1 Common Component Tag AttributesMost of the component tags support the attributes shown in Table 10–2.
All the tag attributes except id can accept expressions, as defined by the EL, describedin Expression Language.An attribute such as rendered or value can be set on the page and then modified inthe backing bean for the page.h:selectOneListbox Allows a user to selectone item from a set ofitems, all displayed atonceAn HTML <select>elementA boxh:selectOneMenu Allows a user to selectone item from a set ofitemsAn HTML <select>elementA menuh:selectOneRadio Allows a user to selectone item from a set ofitemsAn HTML <inputtype="radio">elementA group ofoptionsTable 10–2 Common Component Tag AttributesAttribute Descriptionbinding Identifies a bean property and binds the component instance to it.id Uniquely identifies the component.immediate If set to true, indicates that any events, validation, and conversion associatedwith the component should happen when request parameter values areapplied,rendered Specifies a condition under which the component should be rendered. If thecondition is not satisfied, the component is not rendered.style Specifies a Cascading Style Sheet (CSS) style for the tag.
