javaweb--Filter过滤器，登录验证

青旅半醒 2022-09-11 12:22 236阅读 0赞

## 登录验证过滤器 ##

package cn.itcast.web.filter;
    
    import javax.servlet.*;
    import javax.servlet.annotation.WebFilter;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import java.io.IOException;
    
    /**
     * 登录验证
     */
    @WebFilter("/*")
    public class LoginFilter implements Filter {
        
        public void destroy() {
        
        }
    
        public void doFilter(ServletRequest requset, ServletResponse response, FilterChain chain) throws ServletException, IOException {
        
            //1.强制转换
            HttpServletRequest request =(HttpServletRequest) requset;
    
            //1.获取资源请求路径
            String uri = ((HttpServletRequest) requset).getRequestURI();
            //2.判断是否包含登录相关资源路径,要注意排除css，js，图片，验证码
            if (uri.contains("/login.jsp")||uri.contains("/loginServlet")||uri.contains("/checkCodeServlet") ||uri.contains("/css")||uri.contains("/js")||uri.contains("/fonts")){
        
                //包含，用户就是想登录
                chain.doFilter(requset, response);
            }else {
        
    
                //不包含，判断用户是否登录
                //3、获取session 中User
                Object user = request.getSession().getAttribute("user");
                if (user != null){
        
                    chain.doFilter(requset, response);
                }else{
        
                    //没有登录。跳转登录
                    request.setAttribute("login_msg","您尚未登录，请登录");
                    request.getRequestDispatcher("/login.jsp").forward(request,response);
                }
    
            }
    
            //放行
            //chain.doFilter(requset, response);
        }
    
        public void init(FilterConfig config) throws ServletException {
        
    
        }
    
    }