#{facesContext} EL expression not resolved at runtime

问题

I am working on JSF 1.x On an example stated in JavaServer Faces in Action.

My EL expression of 'Faces Context' is not executing at run time in command button on retrieving the image.

My Project Structure is as follows:

I have not used any Java code in this example, And it contains only one Login Page.

The login.jsp is as follows:

<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h"%>
<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f"%>


<f:view>
<html>
<head>
    <link rel="stylesheet" type="text/css" href="stylesheet.css" />

    <script type="text/javascript">
        function set_image(button, image){
            button.src = img;
        }
    </script>

    <title><h:outputText value="ProjectTrack" /></title>
</head>

<body>

    <h:form>
        <h:panelGrid columns="2" border="0" cellpadding="3" cellspacing="3">

            <h:graphicImage url="/images/logo.png"
                    alt="Welcome to ProjectTrack" title="Welcome to ProjectTrack"
                    width="149" height="160" />


            <h:panelGrid columns="3" border="0" cellpadding="5" cellspacing="3" headerClass="login-heading">

                <f:facet name="header">
                    <h:outputText value="ProjectTrack" />
                </f:facet>

                <h:outputLabel for="userNameInput" >
                    <h:outputText value="Enter your user name: " />
                </h:outputLabel>

                <h:inputText id="userNameInput" size="20" maxlength="30" required="true">
                    <f:validateLength minimum="5" maximum="30"/>
                </h:inputText>

                <h:message for="userNameInput" />

                <h:outputLabel for="passwordInput">
                    <h:outputText value="Password"/>
                </h:outputLabel>

                <h:inputSecret id="passwordInput" size="20" maxlength="20" required="true">
                    <f:validateLength minimum="5" maximum="15" />
                </h:inputSecret>

                <h:message for="passwordInput" />

                <h:panelGroup>
                    <h:commandButton  action="success" 
                                image="#{facesContext.externalContext.requestContextPath}/images/submit.gif" 
                                onmouseover="set_image(this, '#{facesContext.externalContext.requestContextPath}/images/submit_over.gif');"
                                onmouseout="set_image(this, '#{facesContext.externalContext.requestContextPath}/images/submit.gif');" 
                            />
                </h:panelGroup>

            </h:panelGrid>

        </h:panelGrid>
    </h:form>
</body>
</f:view>
    </html>

My Deployment Descriptor web.xml is as follows:

<web-app version="2.5"
      xmlns="http://java.sun.com/xml/ns/javaee"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
      http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

    <display-name>Project Track</display-name>
    <description>Sample Project</description>

    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>/faces/*</url-pattern>
    </servlet-mapping>

    <welcome-file-list>
        <welcome-file>faces/login.jsp</welcome-file>
    </welcome-file-list>


</web-app>

Faces-config.xml is as follows:

<?xml version="1.0"?>
<!DOCTYPE faces-config PUBLIC
     "-//Sun Microsystems, Inc.//DTD JavaServer Faces Config 1.0//EN"
     "http://java.sun.com/dtd/web-facesconfig_1_0.dtd">

<faces-config>

    <application>
        <message-bundle>ptrackResources</message-bundle>
    </application>

    <navigation-rule>
        <from-view-id>/login.jsp</from-view-id>
        <navigation-case>
            <from-outcome>success</from-outcome>
            <to-view-id>/inbox.jsp</to-view-id>
        </navigation-case>
        <navigation-case>
            <from-outcome>failure</from-outcome>
            <to-view-id>/login.jsp</to-view-id>
        </navigation-case>
    </navigation-rule>

</faces-config>

My Maven Dependencies are as follows:

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.achutha.labs</groupId>
  <artifactId>03JsfExample</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <name>03JsfExample</name>
  <description>Project Track</description>

  <dependencies>

        <dependency>
            <groupId>javax.faces</groupId>
            <artifactId>jsf-api</artifactId>
            <version>1.2_14</version>
        </dependency>
        <dependency>
            <groupId>javax.faces</groupId>
            <artifactId>jsf-impl</artifactId>
            <version>1.2_14</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.1</version>
        </dependency>

        <!-- EL -->
        <dependency>
            <groupId>org.glassfish.web</groupId>
            <artifactId>el-impl</artifactId>
            <version>2.2</version>
        </dependency>

    </dependencies>


    <build>
        <finalName>JavaServerFaces</finalName>

        <plugins>

            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>tomcat-maven-plugin</artifactId>
                <configuration>
                    <url>http://localhost:8090/manager/text</url>
                    <server>TomcatServer</server>
                    <path>/balaji</path>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.1</version>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                </configuration>
            </plugin>
        </plugins>
    </build>



</project>

The Application Ran successfully. But the Image for submit button is not displaying which is retrieved through a run time expression.

Browser Display:

I have configured my JBoss tools, from which i can see the preview which evaluates the expression and displays the submit button before deployment:

Eclipse Screen Shot:

The EL expression used in is not evaluating at runtime.

<h:commandButton  action="success" 
                                image="#{facesContext.externalContext.requestContextPath}/images/submit.gif" 
                                onmouseover="set_image(this, '#{facesContext.externalContext.requestContextPath}/images/submit_over.gif');"
                                onmouseout="set_image(this, '#{facesContext.externalContext.requestContextPath}/images/submit.gif');" 
                            />

I have to use JSF 1.x and cannot upgrade it to JSF 2. Please suggest me the solution, and help me know what is going wrong.

My problem is similar to the problem stated here in this link: FacesContext not resolved at run-time

EDIT:

I just added a Debug statement in login.jsp which is as follows:

<h:outputText value=" Debug test for EL exp : #{facesContext.externalContext.requestContextPath}/images/submit.gif" />

Debug Result:

The expression is getting evaluated at runtime, But I feel the result must not contain /balaji/images/submit.gif, And it should only contain /images/submit.gif.

回答1:

The implicit EL variable #{facesContext} is only available in JSF2. The shorthand #{request} as suggested in a comment is only available in Facelets.

You're using JSF1 on JSP. You should be using ${pageContext.request.contextPath} instead.

Unrelated to the concrete problem, the <h:commandButton image> is already context-relative. You don't need to specify it in there. It's only mandatory for your JS mouseover/out functions.

回答2:

You have set an url-pattern containing /faces/*, you must access your JSF pages using this pattern or change to another pattern. Example of other pattern:

<servlet-mapping>
    <servlet-name>Faces Servlet</servlet-name>
    <url-pattern>*.face</url-pattern>
  </servlet-mapping>
  <context-param>
    <param-name>javax.faces.DEFAULT_SUFFIX</param-name>
    <param-value>.xhtml</param-value>
  </context-param>
  <security-constraint>
    <display-name>Disallow direct access to the XHTML Documents</display-name>
    <web-resource-collection>
      <web-resource-name>XHTML</web-resource-name>
      <url-pattern>*.xhtml</url-pattern>
    </web-resource-collection>
    <auth-constraint />
  </security-constraint>

来源：https://stackoverflow.com/questions/15002141/facescontext-el-expression-not-resolved-at-runtime

标签

java

jsp

jsf

jsf-1.2