我面临的问题是<p:commandButton>withid="emailav"不调用 action method emailAvailability。我在里面使用它，p:wizard并且我在里面包含了以下代码块h:form。
1）xhtml
<p:tab id="personal" title="Personal">
<p:panel header="Personal Details" style="font-size:small">
<h:panelGrid columns="3" columnClasses="label, value"
styleClass="grid">
<h:outputText value="Username*" />
<p:inputText id="usrname" required="true" label="Username"
value="#{registrationBean.user.userName}"
requiredMessage="Username required" />
<p:message for="usrname"></p:message>
<h:outputText value="Firstname: *" />
<p:inputText id="frstname" required="true" label="Firstname"
value="#{registrationBean.user.firstName}"
requiredMessage="Firstname required" />
<p:message for="frstname"></p:message>
<h:outputText value="Lastname: *" />
<p:inputText id="lstname" required="true" label="Lastname"
value="#{registrationBean.user.lastName}"
requiredMessage="Lastname required" />
<p:message for="lstname"></p:message>
<h:outputText value="Password: *" />
<p:password id="pwd1" value="#{registrationBean.user.password}"
feedback="true" match="pwd2" label="Password" required="true"
requiredMessage="Password required" />
<p:message for="pwd1"></p:message>
<h:outputText value="Confirm Password: *" />
<p:password id="pwd2" value="#{registrationBean.user.password}"
label="Confirm Password" required="true"
requiredMessage="Enter the password again" />
<p:message for="pwd2"></p:message>
<h:outputText value="Date of Birth(dd/MM/yyyy):" />
<p:inputText id="dob" label="Date of Birth"
value="#{registrationBean.user.birthDate}" />
<p:message for="dob"></p:message>
<h:outputText value="Gender: " />
<p:selectOneMenu id="gender" value="#{registrationBean.user.gender}">
<f:selectItem itemLabel="Select One" itemValue="" />
<f:selectItem itemLabel="Male" itemValue="Male" />
<f:selectItem itemLabel="Female" itemValue="Female" />
<f:selectItem itemLabel="Other" itemValue="Other" />
</p:selectOneMenu>
<p:message for="gender"></p:message>
<h:outputText value="Relationship Status: " />
<p:selectOneMenu id="relationship"
value="#{registrationBean.user.relationship}">
<f:selectItem itemLabel="Select One" itemValue="" />
<f:selectItem itemLabel="Single" itemValue="Single" />
<f:selectItem itemLabel="Committed" itemValue="Committed" />
<f:selectItem itemLabel="Open relationship" itemValue="Open relationship" />
<f:selectItem itemLabel="Its comlicated" itemValue="Its complicated" />
</p:selectOneMenu>
<p:message for="relationship"></p:message>
<h:outputText value="Email: *" />
<p:inputText id="email" label="Email"
value="#{registrationBean.user.email}" required="true"
requiredMessage="Email required"/>
<p:message for="email"/>
<p:commandButton id="emailav" value="email availability"
action="#{registrationBean.emailAvailability}" update="emailav" />
<p:message for="emailav"></p:message>
<p:commandButton style="display:none"/>
<h:outputText value="Skip to last: " />
<h:selectBooleanCheckbox value="#{registrationBean.skip}" />
</h:panelGrid>
</p:panel>
</p:tab>
2）背豆
public String emailAvailability() {
logger.info("inside emailAvailability");
FacesContext context = FacesContext.getCurrentInstance();
Query query = em.createQuery("SELECT u FROM User u", User.class);
List<User> results = query.getResultList();
Iterator<User> it = results.listIterator();
while (it.hasNext()) {
if (it.next().getEmail().equals(user.getEmail())) {
context.addMessage(null,
new FacesMessage("Email already taken"));
}
}
context.addMessage(null, new FacesMessage("Email not taken"));
return "success";
}