javax.faces.FacesException: java.lang.ClassCastException: java.lang.String cannot be cast to javax.faces.component.UIComponent

问题

My Java EE web application is working fine with Glassfish 2.1. Now I want to migrate to Glassfish 3.1.1

I have followed the modifications provided here

my dependencies for richfaces are as follow:-

   <dependency>
        <groupId>org.richfaces.framework</groupId>
        <artifactId>richfaces-api</artifactId>
        <version>3.3.3.Final</version>
    </dependency>
    <dependency>
        <groupId>org.richfaces.framework</groupId>
        <artifactId>richfaces-impl-jsf2</artifactId>
        <version>3.3.3.Final</version>
    </dependency>
    <dependency>
        <groupId>org.richfaces.ui</groupId>
        <artifactId>richfaces-ui</artifactId>
        <version>3.3.3.Final</version>
    </dependency>

my jsf dependencies are

        <dependency>
            <groupId>com.sun.faces</groupId> 
            <artifactId>jsf-api</artifactId> 
            <version>2.0.2</version> 
        </dependency>
        <dependency>
            <groupId>com.sun.faces</groupId> 
            <artifactId>jsf-impl</artifactId> 
            <version>2.0.2</version> 
        </dependency>

added context param in web.xml as follow:-

<context-param>
    <param-name>org.ajax4jsf.VIEW_HANDLERS</param-name>
    <param-value>com.sun.facelets.FaceletViewHandler</param-value>
</context-param>
<context-param>
    <param-name>javax.faces.DISABLE_FACELET_JSF_VIEWHANDLER</param-name>
    <param-value>true</param-value>
</context-param>

modified my application descriptor with version 2.5 like:

<web-app version="2.5" 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/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

my in faces-config is as follow:-

 <application>
        <navigation-handler >
            org.navigation.CustomNavigationHandler
        </navigation-handler>

        <view-handler>
            org.ajax4jsf.application.AjaxViewHandler
        </view-handler>
<!--        <view-handler>
            com.sun.facelets.FaceletViewHandler
        </view-handler>-->
        <variable-resolver>org.springframework.web.jsf.DelegatingVariableResolver</variable-resolver>
        <message-bundle>MyMessages</message-bundle>
    </application>

Application get deployed successfully but after that i am getting error of class cast exception at the time starting an application in browser :

server log is as follow:

INFO: myApp was successfully deployed in 21,635 milliseconds.
SEVERE: Error Rendering View[/login.xhtml]
javax.faces.FacesException: java.lang.ClassCastException: java.lang.String cannot be cast to javax.faces.component.UIComponent
    at com.sun.faces.application.ApplicationImpl.createComponentApplyAnnotations(ApplicationImpl.java:1923)

It is working fine in glassfish 2 so i think there is no issue regarding binding of attributes with backing bean.

how can i resolve this??

回答1:

java.lang.ClassCastException: java.lang.String cannot be cast to javax.faces.component.UIComponent at com.sun.faces.application.ApplicationImpl.createComponentApplyAnnotations

This particular exception will occur when you have a String value property like

private String value;

and are binding it to a component using the binding attribute:

<h:inputText binding="#{bean.value}" />

This is incorrect. The value should be bound using the value attribute:

<h:inputText value="#{bean.value}" />

The binding is only to be used to bind the whole component (which is an instance of UIComponent) to the backing bean, for example to programmaticlly modify it.

Verify your login.xhtml code. If necessary cut out as much as possible code as long as you can still reproduce the problem so that you can end up with the smallest possible code snippet which reproduces exactly this problem which should allow you to find the culprit easier.

See also:

• How does the 'binding' attribute work in JSF? When and how should it be used?

来源：https://stackoverflow.com/questions/8851067/javax-faces-facesexception-java-lang-classcastexception-java-lang-string-canno