java - 没有导航没有例外

Question

xhtml 页面中的表单：

<h:form>
            <h:selectOneMenu id="gender" required="true"
                requiredMessage="#{msg['field.email.REQUIRED']}"
                value="#{registerController.gender}">
                <f:selectItems value="#{registerController.genders}" var="gender"
                    itemLabel="#{gender}" itemValue="#{gender}"></f:selectItems>
            </h:selectOneMenu>

            <p:commandButton value="Cont"
                action="#{registerController.genderEntered()}" />
            <h:link value="Back" outcome="/view/login.xhtml" />

        </h:form>

注册控制器.java

public String genderEntered(){
        return "email.xhtml";
    }

我删除 required="true" 但问题仍然存在。也不例外，但导航不去 email.xhtml