Why the form id prefix in the h:message output?

I'm currently trying simple validation using required="true"

    <h:form>
        <h:messages globalOnly="true"/>
        <h:panelGrid>
            <h:panelGrid columns="3">
                <f:facet name="header">
                    Login Application Sample
                </f:facet>

                <h:outputLabel for="UserId" value="User Id" />
                <h:inputText id="UserId" value="#{userBean.userId}" required="true" />
                <h:message for="UserId"/>

                <h:outputLabel for="Password" value="Password" />
                <h:inputSecret id="Password" value="#{userBean.password}" required="true" />
                <h:message for="Password" />

                <f:facet name="footer">
                    <h:commandButton value="Login" action="#{userBean.login}"/>
                    <h:commandButton type="reset" value="Reset"/>
                </f:facet>
            </h:panelGrid>
        </h:panelGrid>
    </h:form>

Leaving the fields blank, and then clickin on the login button, these error messages will display on the right side of each field :

j_idt7:UserId: Validation Error: Value is required.

j_idt7:Password: Validation Error: Value is required.

This is what I expected, but I don't want to display the form id prefix of 'j_idt7:'. I read book examples, they don't output the form id prefix. What I want is :

UserId: Validation Error: Value is required.

Password: Validation Error: Value is required.

What should I do to skip displaying the form id prefix开发者_如何学Python in the component specific messages ?

I'm currently testing JSF 2 in glassfish v3.

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The message label defaults to component's client ID, exactly the one as you can see in generated HTML output via rightclick, View Source. That j_id7 is in this particular case the client ID of the parent <form> element. If you give the JSF component a fixed ID like <h:form id="login"> then the labels will become login:UserId and login:Password respectively.

You can however use the input component's label attribute to override it altogether so that the message label will be shown exactly as you intented.

<h:inputText ... label="User ID" />
<h:inputSecret ... label="Password" />

If the input component's label attribute is present, then it will be used instead of the client ID. Using prependId="false" as suggested by other answers has disadvantages. Don't do that.

A completely different alternative is to use requiredMessage (or converterMessage or validatorMessage) attribute for this, but this doesn't allow parameterizing messages and thus you'd have to hardcode the labels and such.

<h:inputText ... label="User ID is required." />
<h:inputSecret ... label="Password is required." />

See also:

• Change the default message "Validation Error: Value is required" to just "Value is required"
• Getting the component id on the error validation message
• How to parameterize requiredMessage attribute in composite component?

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Noted should be that it's indeed awkward to have labels duplicated like this:

<h:outputLabel for="userId" value="User ID" ... />
<h:inputText id="userId" ... label="User ID" />

<h:outputLabel for="password" value="Password" ... />
<h:inputSecret id="password" ... label="Password" />

If you happen to use JSF utility library OmniFaces, then you can use <o:outputLabel> to let JSF transparently set the label attribute of the associated component:

<o:outputLabel for="userId" value="User ID" ... />
<h:inputText id="userId" ... />

<o:outputLabel for="password" value="Password" ... />
<h:inputSecret id="password" ... />

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If you use MyFaces and the bean validation framework (JSR303) try to define a MessageBundle with a key javax.faces.validator.BeanValidator.MESSAGE

faces-config.xml

<application>
    <message-bundle>ApplicationMessages</message-bundle>
</application>

ApplicationMessages.properties

#javax.faces.validator.BeanValidator.MESSAGE={1}: {0}
javax.faces.validator.BeanValidator.MESSAGE={0}

Details

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You need to override these messages from JSF.

You can have a messages.properties file in your classpath

Messages.properties

javax.faces.component.UIInput.REQUIRED=Field must be entered.  

Faces-config.xml

<application>
      <message-bundle>Messages</message-bundle>
      <locale-config>
          <default-locale>en</default-locale>

      </locale-config>
  </application>    

Have a look at this Article

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If you care to see the HTML source from your browser, you will find out that the id of your input field is <form-id>+":"+<input-field-id>, in your case, j_idt7:UserId:. Try to give your <h:form> some meaningful id in order to make some sense out of it. You can read about JSF IDs here. In case you don't like it, you can turn it off by modifying your form tag to something like this,

<h:form prependId = false> // its true by default.

But that might turn out to be problematic, as pointed out by BalusC here.

Furthermore, it seems like you have never configured any validation messages yourself. Which in turn ends up with this message. Hence, a message.properties file is needed to have a control over message and show something more appropriate. Even then the field name should not be the part of the message, to make those validation message generic to avoid repetition. See BalusC's answer regarding the use of label attribute inside the <h:inputText>.

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Where you are writing required = true, there you can define requiredMessage = "My Message" for any input type.

e.g.

<h:inputText autocomplete="false" id = "CellNumber" label="Cell Number" required="true" requiredMessage="Cell Number Required" maxlength="10" value="#{userManagedBean.cellNumber}" >