如何检查用户是否登录? [英] How to check if is user logged in?

问题描述

我想在用户未登录时显示登录链接，并在用户登录时显示注销链接.我正在使用web.xml中定义的容器管理的安全性.

I want do display a login link when the user isn't logged in and a logout link when the user is logged in. I'm using container managed security as defined in web.xml.

我该如何实现?

推荐答案

The username of the logged-in user is available by ExternalContext#getRemoteUser() which delegates under the covers to HttpServletRequest#getRemoteUser(). Both are available in EL by #{facesContext.externalContext.remoteUser} and #{request.remoteUser} respectively. If it is null, then it means that the user is not logged in.

因此，在您看来，您可以在rendered属性中对其进行检查，如下所示:

So, in your view you can check it in the rendered attribute as follows:

<h:form rendered="#{not empty request.remoteUser}">
    <h:commandLink value="Logout" action="#{auth.logout}" />
</h:form>
<h:link value="Login" outcome="login" rendered="#{empty request.remoteUser}" />

另请参见:

• 有条件地显示JSF组件

See also:

• Conditionally displaying JSF components

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