java – 如何处理/限制对servlet和jsp的用户访问？

适应您的问题的代码(注意需求的验证方法的添加和使用)：

@WebFilter("/*")
public class LoginFilter implements Filter {
    @Override
    public void init(FilterConfig config)
        throws ServletException {
        // If you have any <init-param> in web.xml,then you could get them
        // here by config.getInitParameter("name") and assign it as field.
    }

    @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);

        String requestPath = httpServletRequest.getRequestURI();

        if (needsAuthentication(requestPath) ||
            session == null ||
            session.getAttribute("user") == null) { // change "user" for the session attribute you have defined

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

    @Override
    public void destroy() {
        // If you have assigned any expensive resources as field of
        // this Filter class,then you could clean/close them here.
    }

    //basic validation of pages that do not require authentication
    private boolean needsAuthentication(String url) {
        String[] validNonAuthenticationUrls =
            { "Login.jsp","Register.jsp" };
        for(String validUrl : validNonAuthenticationUrls) {
            if (url.endsWith(validUrl)) {
                return false;
            }
        }
        return true;
    }
}

我建议将需要身份验证的所有页面移动到像应用程序这样的文件夹中,然后将Web过滤器更改为

@WebFilter("/app/*")

这样,您可以从过滤器中删除needsAuthentication方法.