检查会话是否存在 JSF [英] Check if session exists JSF

问题描述

我有一个登录页面，我有一个用户 bean 来验证一个人的用户名和密码.这个 Bean 是会话范围的.如果有人写了一个 URL 并试图跳转登录页面，我该如何检查并将他重定向到登录页面?

I have a login page where I have a User bean to authenticate username and password for a person. This Bean is Session Scoped. If someone writes a URL and tries to jump the login page, how can I check that and redirect him to the login page?

另一方面.假设我已经登录并且正在工作，突然我出去了一段时间并且我的会话过期.当我返回并尝试与表单交互时，它会发送一条消息，提醒我会话到期.发生这种情况时，如何再次重定向到登录表单?

On the other hand. Suppose I have logged in and I was working and suddenly I go out for a while and my session expires. When I return and try to interact with the form it sends a message alerting me the session expiration. How can I redirecto again to the login form when this occurs?

提前致谢.希望我解释一下.

Thanks in advance. Hope I explain myself.

Mojarra 2.1.4、Tomcat 7、战斧 1.1.11

Mojarra 2.1.4, Tomcat 7, Tomahawk 1.1.11

推荐答案

如果有人写了一个 URL 并试图跳转登录页面，我该如何检查并将他重定向到登录页面?

您似乎在使用自产身份验证.在这种情况下，您需要实现一个 servlet 过滤器.JSF 将会话范围的托管 bean 存储为 HttpSession 的属性，因此您可以在 doFilter() 方法中检查它:

You seem to using homegrown authentication. In that case, you need to implement a servlet filter. JSF stores session scoped managed beans as attributes of HttpSession, so you could just check on that in doFilter() method:

HttpServletRequest req = (HttpServletRequest) request;
UserManager userManager = (UserManager) req.getSession().getAttribute("userManager");

if (userManager != null && userManager.isLoggedIn()) {
    chain.doFilter(request, response);
} else {
    HttpServletResponse res = (HttpServletResponse) response;
    res.sendRedirect(req.getContextPath() + "/login.xhtml");
}

将此过滤器映射到覆盖受保护页面的 URL 模式上，例如/app/*.

Map this filter on an URL pattern covering the secured pages, e.g. /app/*.

当我返回并尝试与表单交互时，它会发送一条消息，提醒我会话到期.发生这种情况时，我如何再次重定向到登录表单?

我知道这与 Ajax 请求有关吗?对于普通请求，您可以在 web.xml 中使用 .如果在web.xml中将状态保存方式设置为client如下

I understand that this concerns Ajax requests? For normal requests you could have used an <error-page> in web.xml. If setting the state saving method to client in web.xml as follows

<context-param>
    <param-name>javax.faces.STATE_SAVING_METHOD</param-name>
    <param-value>client</param-value>
</context-param>

不是一个选项，那么你需要实现一个自定义的ExceptionHandler:

is not an option, then you need to implement a custom ExceptionHandler:

public class ViewExpiredExceptionHandler extends ExceptionHandlerWrapper {

    private ExceptionHandler wrapped;

    public ViewExpiredExceptionHandler(ExceptionHandler wrapped) {
        this.wrapped = wrapped;
    }

    @Override
    public void handle() throws FacesException {
        FacesContext facesContext = FacesContext.getCurrentInstance();

        for (Iterator<ExceptionQueuedEvent> iter = getUnhandledExceptionQueuedEvents().iterator(); iter.hasNext();) {
            Throwable exception = iter.next().getContext().getException();

            if (exception instanceof ViewExpiredException) {
                facesContext.getApplication().getNavigationHandler().handleNavigation(facesContext, null, "viewexpired");
                facesContext.renderResponse();
                iter.remove();
            }
        }

        getWrapped().handle();
    }

    @Override
    public ExceptionHandler getWrapped() {
        return wrapped;
    }

}

(请注意，此特定示例导航到 viewexpired，因此它期望 /viewexpired.xhtml 作为错误页面)

(note that this particular example navigates to viewexpired, so it expects a /viewexpired.xhtml as error page)

以上需要通过以下ExceptionHandlerFactory 实现:

The above needs to be baked by the following ExceptionHandlerFactory implementation:

public class ViewExpiredExceptionHandlerFactory extends ExceptionHandlerFactory {

    private ExceptionHandlerFactory parent;

    public ViewExpiredExceptionHandlerFactory(ExceptionHandlerFactory parent) {
        this.parent = parent;
    }

    @Override
    public ExceptionHandler getExceptionHandler() {
        return new ViewExpiredExceptionHandler(parent.getExceptionHandler());
    }

}

依次需要在faces-config.xml中注册如下:

which in turn needs to be registered in faces-config.xml as follows:

<factory>
    <exception-handler-factory>com.example.ViewExpiredExceptionHandlerFactory</exception-handler-factory>
</factory>

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