无法在WildFly 21上使用JSF 2.2访问CDI Backing Bean

Question

我一直在遵循本教程，在Windows10的Wildfly-21.0服务器上使用JAVA-14和Maven在Eclipse版本2020-09(4.17.0(上安装JSF。在完成页面上的说明后，我可以浏览到我的index.xhtml页面，但当我提交表单时，我无法访问backingbean。我得到了以下错误：

[javax.enterprise.resource.webcontainer.jsf.context] (default task-1) javax.el.PropertyNotFoundException: /index.xhtml @14,61 value="#{bean.input}": Target Unreachable, identifier 'bean' resolved to null: javax.el.PropertyNotFoundException: /index.xhtml @14,61 value="#{bean.input}": Target Unreachable, identifier 'bean' resolved to null
at [e-mail]01//com.sun.faces.facelets.el.TagValueExpression.getType(TagValueExpression.java:64)
at [e-mail]01//com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getConvertedValue(HtmlBasicInputRenderer.java:71)
at [e-mail]04//javax.faces.component.UIInput.getConvertedValue(UIInput.java:1110)
at [e-mail]04//javax.faces.component.UIInput.validate(UIInput.java:1011)
at [e-mail]04//javax.faces.component.UIInput.executeValidate(UIInput.java:1322)
at [e-mail]04//javax.faces.component.UIInput.processValidators(UIInput.java:733)
at [e-mail]04//javax.faces.component.UIForm.processValidators(UIForm.java:229)
at [e-mail]01//com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:608)
at [e-mail]01//com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:159)
at [e-mail]04//javax.faces.component.UIComponent.visitTree(UIComponent.java:1456)
at [e-mail]04//javax.faces.component.UIForm.visitTree(UIForm.java:355)
at [e-mail]04//javax.faces.component.UIComponent.visitTree(UIComponent.java:1468)
at [e-mail]04//javax.faces.component.UIComponent.visitTree(UIComponent.java:1468)
at [e-mail]01//com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:400)
at [e-mail]01//com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:261)
at [e-mail]04//javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1308)
at [e-mail]01//com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:53)
at [e-mail]01//com.sun.faces.lifecycle.Phase.doPhase(Phase.java:76)
at [e-mail]01//com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:177)
at [e-mail]04//javax.faces.webapp.FacesServlet.executeLifecyle(FacesServlet.java:707)
at [e-mail]04//javax.faces.webapp.FacesServlet.service(FacesServlet.java:451)
at [e-mail]//io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)
at [e-mail]//io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
at io.opentracing.contrib.opentracing-jaxrs2//io.opentracing.contrib.jaxrs2.server.SpanFinishingFilter.doFilter(SpanFinishingFilter.java:52)
at [e-mail]//io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at [e-mail]//io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at [e-mail]//io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
at [e-mail]//io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at [e-mail]//io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68)
at [e-mail]//io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at [e-mail]//org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at [e-mail]//io.undertow.servlet.handlers.RedirectDirHandler.handleRequest(RedirectDirHandler.java:68)
at [e-mail]//io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:132)
at [e-mail]//io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at [e-mail]//io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at [e-mail]//io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at [e-mail]//io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at [e-mail]//io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at [e-mail]//io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at [e-mail]//io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at [e-mail]//org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at [e-mail]//org.wildfly.extension.undertow.deployment.GlobalRequestControllerHandler.handleRequest(GlobalRequestControllerHandler.java:68)
at [e-mail]//io.undertow.servlet.handlers.SendErrorPageHandler.handleRequest(SendErrorPageHandler.java:52)
at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:269)
at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:78)
at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:133)
at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:130)
at [e-mail]//io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
at [e-mail]//io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at [e-mail]//org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105)
at [e-mail]//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at [e-mail]//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at [e-mail]//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at [e-mail]//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at [e-mail]//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:249)
at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:78)
at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:99)
at [e-mail]//io.undertow.server.Connectors.executeRootHandler(Connectors.java:387)
at [e-mail]//io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:841)
at [e-mail]//org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
at [e-mail]//org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1990)
at [e-mail]//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
at [e-mail]//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377)
at [e-mail]//org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1280)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: javax.el.PropertyNotFoundException: Target Unreachable, identifier 'bean' resolved to null
at [e-mail]-2//com.sun.el.parser.AstValue.getTarget(AstValue.java:148)
at [e-mail]-2//com.sun.el.parser.AstValue.getType(AstValue.java:62)
at [e-mail]-2//com.sun.el.ValueExpressionImpl.getType(ValueExpressionImpl.java:160)
at [e-mail]//org.jboss.weld.module.web.el.WeldValueExpression.getType(WeldValueExpression.java:93)
at [e-mail]//org.jboss.weld.module.web.el.WeldValueExpression.getType(WeldValueExpression.java:93)
at [e-mail]01//com.sun.faces.facelets.el.TagValueExpression.getType(TagValueExpression.java:62)
... 70 more

在eclipse中，我的项目的属性；Project Facets"；我不能将JavaServerFaces版本设置为2.3；无法将项目方面JavaServerFaces的版本更改为2.3"；。所以我选择了2.2版本。根据这个堆栈溢出的帖子，我的CDI实现可能有问题。

关于我如何解决这个问题并继续前进，有什么建议吗？

提前感谢！

我的POM文件：

<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>tanvir.project</groupId>
<artifactId>SudokuSolver</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<name>Sudoku Solver</name>
<description>Webapp for solving sudoku puzzles</description>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<maven.compiler.source>14</maven.compiler.source>
<maven.compiler.target>14</maven.compiler.target>
<failOnMissingWebXml>false</failOnMissingWebXml>
</properties>
<dependencies>
<dependency>
<groupId>jakarta.platform</groupId>
<artifactId>jakarta.jakartaee-api</artifactId>
<version>9.0.0</version>
<scope>provided</scope>
</dependency>
</dependencies>

我的WEB-INF/beans.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
version="1.1" bean-discovery-mode="all">
</beans>

我的WEB-INF/faces-config.xml：

<?xml version="1.0" encoding="UTF-8"?>
<faces-config xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-facesconfig_2_2.xsd"
version="2.2">
<!-- JSF configuration here. -->
</faces-config>

我的支持豆：

package tanvir.project.sudoku;
import jakarta.enterprise.context.RequestScoped;
import jakarta.inject.Named;
@Named
@RequestScoped
public class Bean {
private String input;
private String output;
public void submit() {
output = "Hello World! You have typed: " + input;
}
public String getInput() {
return input;
}
public void setInput(String input) {
this.input = input;
}
public String getOutput() {
return output;
}
}

最后，我的xhtml文件：

<!DOCTYPE html>
<html lang="en"
xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://xmlns.jcp.org/jsf/core"
xmlns:h="http://xmlns.jcp.org/jsf/html"
>
<h:head>
<title>Hello World</title>
</h:head>
<h:body>
<h1>Hello World</h1>
<h:form>
<h:outputLabel for="input" value="Input" />
<h:inputText id="input" value="#{bean.input}" />
<h:commandButton value="Submit" action="#{bean.submit}">
<f:ajax execute="@form" render=":output" />
</h:commandButton>
</h:form>
<h:outputText id="output" value="#{bean.output}" />
</h:body>
</html>

Answer 1

由于没有使用jakarta.jakartaee-api版本8.0.0，如教程中所述，我使用了版本9.0.0。这需要我在Bean.java中导入javax.inject.Name的jakarta.inject.Name以使用@Named注释。当我在POM文件中将jakarta.jakartaee-api版本设置为8.0.0时，问题得到了解决(现在可以使用EL语句引用backingbean(。