How to use JSF's pass-through attributes with

2019-05-29 04:43发布

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问题:

I use h:selectOneMenu and f:selectItems and want to add title attribute to HTML's option tag. It works fine with a static value:

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://xmlns.jcp.org/jsf/html"
      xmlns:f="http://xmlns.jcp.org/jsf/core"
      xmlns:p="http://xmlns.jcp.org/jsf/passthrough">
//... body / form
    <h:selectOneMenu id="select-opts" value="#{bean.option}">
        <f:selectItems value="#{bean.allOptions}" var="option" itemLabel="#{option.name}" p:title="static value" />
    </h:selectOneMenu>
//...

The same title="static value" is added to each option.

But if I try p:title="#{option.description}" there's a NullPointerException (stacktrace further below)
and with p:title="#{bean.getTitle(option)}" the option parameter is always null.

What am I doing wrong?
Is there a way to generate values of a pass-through attribute based on each value of selectItems (without having to write a custom Renderer as this answer suggests)?

PS: in pre-JSF-2.2 I did this with javascript/jQuery; in case someone needs this:

var getTitles = fucntion(val) {...};
jQuery('[id$=select-opts] > option').each(function(){
    var opt = jQuery(this);
    opt.attr({'title' : getTitles(opt.val())});
});

But I hope there's a cleaner solution with pass-through attributes.

Environment: Wildfly 8.0.0.Final, JSF-2.2.5

NPE stacktrace:

SEVERE [javax.enterprise.resource.webcontainer.jsf.application] (default task-1) Error Rendering View[/page.xhtml]: java.lang.NullPointerException
    at com.sun.faces.renderkit.html_basic.HtmlResponseWriter.getAttributeValue(HtmlResponseWriter.java:1211) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.renderkit.html_basic.HtmlResponseWriter.flushAttributes(HtmlResponseWriter.java:1171) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.renderkit.html_basic.HtmlResponseWriter.closeStartIfNecessary(HtmlResponseWriter.java:1113) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.renderkit.html_basic.HtmlResponseWriter.write(HtmlResponseWriter.java:717) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.renderkit.html_basic.MenuRenderer.renderOption(MenuRenderer.java:592) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.renderkit.html_basic.MenuRenderer.renderOptions(MenuRenderer.java:794) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.renderkit.html_basic.MenuRenderer.renderSelect(MenuRenderer.java:847) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.renderkit.html_basic.MenuRenderer.encodeEnd(MenuRenderer.java:297) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at javax.faces.render.Renderer.encodeChildren(Renderer.java:176) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:889) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:461) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:133) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219) [jsf-impl-2.2.5-jbossorg-3.jar:]
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647) [jboss-jsf-api_2.2_spec-2.2.5.jar:2.2.5]
    at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:61) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:25) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:113) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.security.handlers.AuthenticationCallHandler.handleRequest(AuthenticationCallHandler.java:52) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:45) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:61) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:70) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.security.handlers.SecurityInitialHandler.handleRequest(SecurityInitialHandler.java:76) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:25) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
    at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:25) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:25) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:240) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:227) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:73) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:146) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.server.Connectors.executeRootHandler(Connectors.java:168) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:687) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_51]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_51]
    at java.lang.Thread.run(Thread.java:744) [rt.jar:1.7.0_51]
标签： jsf jsf-2.2
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