创建一个过滤器，该过滤器User在会话中不存在来自数据库的关联对象时检查用户是否已登录。然后，只需加载该数据并进行会话即可。

基本上，

@WebFilter("/*")
public class UserFilter implements Filter {

    @EJB
    private UserService service;

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) req;
        String remoteUser = request.getRemoteUser();

        if (remoteUser != null) {
            HttpSession session = request.getSession();

            if (session.getAttribute("user") == null) {
                User user = service.find(remoteUser);
                session.setAttribute("user", user);
            }
        }

        chain.doFilter(req, res);
    }

    // ...
}