java之filter登錄驗證的過濾器，放行靜態資源

登錄驗證的過濾器，放行靜態資源

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

/**
 * 登錄驗證的過濾器
 */
@WebFilter("/*")
public class LoginFilter implements Filter {


    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {
        System.out.println(req);
        //0.強制轉換
        HttpServletRequest request = (HttpServletRequest) req;

        //1.獲取資源請求路徑
        String uri = request.getRequestURI();
        //2.判斷是否包含登錄相關資源路徑,要注意排除掉 css/js/圖片/驗證碼等資源
        if(uri.contains("/login.jsp") || uri.contains("/loginServlet") || uri.contains("/css/") || uri.contains("/js/") || uri.contains("/fonts/") || uri.contains("/checkCodeServlet")  ){
            //包含，用戶就是想登錄。放行
            chain.doFilter(req, resp);
        }else{
            //不包含，需要驗證用戶是否登錄
            //3.從獲取session中獲取user
            Object user = request.getSession().getAttribute("user");
            if(user != null){
                //登錄了。放行
                chain.doFilter(req, resp);
            }else{
                //沒有登錄。跳轉登錄頁面

                request.setAttribute("login_msg","您尚未登錄，請登錄");
                request.getRequestDispatcher("/login.jsp").forward(request,resp);
            }
        }


        // chain.doFilter(req, resp);
    }

    public void init(FilterConfig config) throws ServletException {

    }

    public void destroy() {
    }

}