Why won't work? | 易学教程

问题

I use JSF 2.0, hibernate-validator4.2.jar validation-api.jar tomcat and Eclipse.

I put @Size(min=3, message="xxx") annotation in a @ManagedBean and <f:validateBean /> between <h:inputText value="#{user.name}"></h:inputText>

When I try to run the project i get this error...

exception

javax.servlet.ServletException: Expression Error: Named Object: javax.faces.Bean not found.
    javax.faces.webapp.FacesServlet.service(FacesServlet.java:606)

root cause

javax.faces.FacesException: Expression Error: Named Object: javax.faces.Bean not found.
    com.sun.faces.application.ApplicationImpl.createValidator(ApplicationImpl.java:1593)
    com.sun.faces.facelets.tag.jsf.ValidatorTagHandlerDelegateImpl.createValidator(ValidatorTagHandlerDelegateImpl.java:244)
    com.sun.faces.facelets.tag.jsf.ValidatorTagHandlerDelegateImpl.applyAttachedObject(ValidatorTagHandlerDelegateImpl.java:132)
    com.sun.faces.facelets.tag.jsf.ValidatorTagHandlerDelegateImpl.applyNested(ValidatorTagHandlerDelegateImpl.java:211)
    com.sun.faces.facelets.tag.jsf.ValidatorTagHandlerDelegateImpl.apply(ValidatorTagHandlerDelegateImpl.java:87)
    javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
    javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)

why? (this only appears when i put tag)

User.java

import java.io.Serializable;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import javax.validation.constraints.Size;

@ManagedBean(name="user")
@SessionScoped
public class User{
    @Size(min=3, message="At least 3 characters!")
    private String name;


    public String getName() {
        return nume;
    }
        public void setName(String name){
                this.name=name;
    }

}

adduser.xhtml

<!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:ui="http://java.sun.com/jsf/facelets"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:f="http://java.sun.com/jsf/core">

<ui:composition template="/templates/master_layout.xhtml">
    <ui:define name="text_header" >Panou de control: Adauga user    </ui:define>
    <ui:define name="content">
        <h:panelGrid columns="3">
            <h:outputText value="Name"></h:outputText>
            <h:inputText  value="#{user.name}"> 
                <f:validateBean />
             </h:inputText>

            <h:commandButton value="Inregistreaza" action="index.xhtml"></h:commandButton>
        </h:panelGrid>
    </ui:define>
</ui:composition>
</html>

回答1:

It should work perfectly fine, although the empty <f:validateBean/> tag is entirely superfluous in this context. It's supposed to be used to "finetune" validation more, such as grouping of validation and/or disabling the implicit bean validation on a per-input basis by specifying the desired tag attributes. You have however no attributes on that tag, so just remove that tag altogether. On a default JSF 2 + JSR 303 project setup, it's supposed to kick in fully transparently without adding more JSF tags whenever there's a JSR 303 annotation on the property such as @Size and likes.

But I don't think that removing the tag will solve this particular exception. Your problem lies thus deeper. This validator is supposed to be auto-registered on startup. However, the exception basically tells that the validator is not registered at all. With the information given so far, it's not possible to give a targeted answer. I can think of the following possible causes:

There's a bug in the JSF implementation which you're using. Upgrade it to a newer version.
You have multiple JSF libraries of different versions in your classpath. Cleanup it.
The faces-config.xml root declaration is not declared conform JSF 2.x. Fix it.

来源：https://stackoverflow.com/questions/8508984/why-fvalidatebean-wont-work

标签

jsf

jsf-2

bean-validation

Why <f:validateBean /> won't work?

问题

回答1: