我正在测试https://www.primefaces.org/showcase/ui/overlay/dialog/loginDemo.xhtml上的 PrimeFaces 示例。我在 Eclipse Dynamic web 项目中正确导入了 PrimeFaces 和 JSF 2.1，但是在启动网页（使用 Tomcat）时出现以下错误：
javax.faces.view.facelets.TagException: /login.xhtml at line 30 and column 36 <f:facet> Tag Library supports namespace: http://java.sun.com/jsf/html, but no tag was defined for name: facet
org.apache.myfaces.view.facelets.compiler.CompilationManager.pushTag(CompilationManager.java:282)
org.apache.myfaces.view.facelets.compiler.SAXCompiler$CompilationHandler.startElement(SAXCompiler.java:250)
com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:506)
com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:745)
com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:376)
com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2717)
com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:116)
com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:489)
com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:302)
javax.xml.parsers.SAXParser.parse(SAXParser.java:195)
org.apache.myfaces.view.facelets.compiler.SAXCompiler.doCompile(SAXCompiler.java:739)
org.apache.myfaces.view.facelets.compiler.Compiler.compile(Compiler.java:128)
org.apache.myfaces.view.facelets.impl.DefaultFaceletFactory._createFacelet(DefaultFaceletFactory.java:300)
org.apache.myfaces.view.facelets.impl.DefaultFaceletFactory.access$000(DefaultFaceletFactory.java:53)
org.apache.myfaces.view.facelets.impl.DefaultFaceletFactory$1.newInstance(DefaultFaceletFactory.java:114)
org.apache.myfaces.view.facelets.impl.DefaultFaceletFactory$1.newInstance(DefaultFaceletFactory.java:111)
org.apache.myfaces.view.facelets.impl.FaceletCacheImpl.getFacelet(FaceletCacheImpl.java:83)
org.apache.myfaces.view.facelets.impl.FaceletCacheImpl.getFacelet(FaceletCacheImpl.java:50)
org.apache.myfaces.view.facelets.impl.DefaultFaceletFactory.getFacelet(DefaultFaceletFactory.java:199)
org.apache.myfaces.view.facelets.impl.DefaultFaceletFactory.getFacelet(DefaultFaceletFactory.java:182)
org.apache.myfaces.view.facelets.FaceletViewDeclarationLanguage._getFacelet(FaceletViewDeclarationLanguage.java:2622)
org.apache.myfaces.view.facelets.FaceletViewDeclarationLanguage.buildView(FaceletViewDeclarationLanguage.java:452)
org.apache.myfaces.lifecycle.RenderResponseExecutor.execute(RenderResponseExecutor.java:78)
org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:241)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:199)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.21 logs.
LoginBean.java 包含：
package classi;
import java.awt.event.ActionEvent;
import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import org.primefaces.context.RequestContext;
public class LoginBean
{
private String username;
private String password;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public void login(ActionEvent actionEvent) {
RequestContext context = RequestContext.getCurrentInstance();
FacesMessage msg = null;
boolean loggedIn = false;
if(username != null &&/*&&*/ username.equals("admin") && password != null && password.equals("admin")) {
loggedIn = true;
msg = new FacesMessage(FacesMessage.SEVERITY_INFO, "Welcome", username);
} else {
loggedIn = false;
msg = new FacesMessage(FacesMessage.SEVERITY_WARN, "Login Error", "Invalid credentials");
}
FacesContext.getCurrentInstance().addMessage(null, msg);
context.addCallbackParam("loggedIn", loggedIn);
}
}
login.xhtml 包含：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.org/ui">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Insert title here</title>
</head>
<body>
<h:outputLink id="loginLink" value="javascript:void(0)" onclick="dlg.show()" title="login">
<p:graphicImage value="/images/login.png" />
</h:outputLink>
<p:growl id="growl" showDetail="true" life="3000" />
<p:dialog id="dialog" header="Login" widgetVar="dlg">
<h:form>
<h:panelGrid columns="2" cellpadding="5">
<h:outputLabel for="username" value="Username:" />
<p:inputText value="#{loginBean.username}"
id="username" required="true" label="username" />
<h:outputLabel for="password" value="Password:" />
<h:inputSecret value="#{loginBean.password}"
id="password" required="true" label="password" />
<f:facet name="footer">
<p:commandButton id="loginButton" value="Login" update=":growl"
actionListener="#{loginBean.login}"
oncomplete="handleLoginRequest(xhr, status, args)"/>
</f:facet>
</h:panelGrid>
</h:form>
</p:dialog>
<script type="text/javascript">
function handleLoginRequest(xhr, status, args) {
if(args.validationFailed || !args.loggedIn) {
jQuery('#dialog').effect("shake", { times:3 }, 100);
} else {
dlg.hide();
jQuery('#loginLink').fadeOut();
}
}
</script>
</body>
</html>