Web过滤器,解决未登录用户跳转登录页的功能

Servlet过滤器

过滤器由Servlet提供,拦截器是springmvc提供

功能

通过配置过滤器,来实现未登录的用户访问后台页面的时候直接跳转到登录页面

后台代码范例

@Slf4j
@WebFilter(filterName = "loginCheckFilter",urlPatterns = "/*")
public class LoginCheckFilter implements Filter {

    /**
     * 路径匹配器,针对通配符的这种东西实现匹配的逻辑
     */
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        log.info("拦截到请求: {}",request.getRequestURI());
        /**
         * 获取本次请求uri
         */
        String requestURI = request.getRequestURI();
        /**
         * 定义不需要处理的请求路径
         */
        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**"
        };
        /**
         * 判断本次请求是否需要处理
         */
        boolean check = check(urls, requestURI);
        if (check){
            // 放行
            log.info("本次请求不需要处理")
            filterChain.doFilter(request,response);
            return;
        }
        /**
         * 判断登录状态,如果已登录,则直接放行
         *
         */
        if (request.getSession().getAttribute("employee") != null){
            log.info("用户已登录")
            filterChain.doFilter(request,response);
            return;
        }

        /**
         * 通过输出流的方式向客户端页面响应数据
         */
		 log.info("用户未登录")
        response.getWriter().write(JSON.toJSONString(Result.error(Status.ARGUMENT_ERROR)));
        return;
    }

    /**
     * 检查当前请求是否需要放行
     * @param urls
     * @param requestURI
     * @return
     */
    public boolean check(String[] urls,String requestURI){
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if (match){
                return true;
            }
        }
        return false;
    }
}

springboot启动类上加注解@ServletComponentScna,这个@WebFilter才能生效

前端实现,搭配跳转登录页

前端vue中使用前端内置interceptor去实现,基于返回code和msg,根据接口返回的内容进行匹配,判断当前页面是否需要强制跳转到指定的登录页面中去

service.interceptors.response.use(res => {
	const code = res.data.code;
	const msg = res.data.msg;
	if (res.data.code === 0 && res.data.msg === 'NOTLOGIN') {
		localStorage.removeItem("userInfo")
		window.top.location.href = '/backend/page/login/login.html'
	}else{
		return res.data
	}
	},
	error => {
		let ( message == "Network Error" ) {
			message = "后端接口连接异常";
		}
	}
)