How to provide bean methods without EL expression

问题

As I was told and found on websites, my bean will only be executed if I have a call for it on my .xhtml.

Is it possible to call my bean without any EL expression?

I need this because my HomeController is calling a method that checks for the session status and on my home.xhtml and don't have any need for fall this bean, for now.

回答1:

You need to look for a solution in a different direction.

If you're homegrowing user authentication instead of using container managed authentication, then you normally use a servlet filter for the particular purpose of checking if an user is logged in or not.

The servlet filter can like as servlets (like FacesServlet) be mapped on a particular URL pattern. It will then be invoked on every request matching that URL pattern. You can explore request/session data in the filter and then handle the request/response accordingly by either continuning the filter chain, or by sending a redirect.

You need to implement javax.servlet.Filter interface accordingly. Here's a kickoff example of how the doFilter() method should be implemented assuming that you've a @SessionScoped managed bean LoginController. JSF stores session scoped managed beans as attributes of HttpSession.

@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) res;
    HttpSession session = request.getSession(false);
    LoginController loginController = (LoginController) (session != null) ? session.getAttribute("loginController") : null;

    if (loginController == null || !loginController.isLoggedIn()) {
        response.sendRedirect(request.getContextPath() + "/login.xhtml"); // No logged-in user found, so redirect to login page.
    } else {
        chain.doFilter(req, res); // Logged-in user found, so just continue request.
    }
}

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

@WebFilter("/app/*")
public class LoginFilter implements Filter {
    // ...
}

Update if the login.xhtml is also covered by this URL pattern and you really can't change it, then change the if block as follows:

if (!request.getRequestURI().endsWith("/login.xhtml") && (loginController == null || !loginController.isLoggedIn())) {
    // ...
}

来源：https://stackoverflow.com/questions/10355131/how-to-provide-bean-methods-without-el-expression

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