java-过滤器实现记录访问ip的次数

阳光穿透心脏的1/2处 2022-11-01 05:43 140阅读 0赞

## java-过滤器实现记录访问ip的次数 ##

> 需求：不同用户会访问一个网站下不同的网页，我们需要记录这些用户的ip以及访问该网站的次数。

**过滤器:**

@WebFilter("/user/*")
    public class LoginFilter implements Filter { 
        private Map<String,Integer> count=new HashMap<>(); //存放ip和次数
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException { 
    
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 
            /*String url = String.valueOf(req.getRequestURL()); Pattern compile = Pattern.compile("http://(.*?):8081/login"); Matcher matcher = compile.matcher(url); String group=""; if(matcher.find()){ group = matcher.group(1); System.out.println(group); }*/
            /*向下转型*/
            HttpServletRequest request = (HttpServletRequest) servletRequest;
            /*获得请求域中的访问者ip*/
            String ip=null;
            if (request.getHeader("x-forwarded-for") == null) { 
                ip=request.getRemoteAddr();
            }else { 
                ip=request.getHeader("x-forwarded-for");
            }
    
            /*检测map集合中是否有该ip*/
            if(count.containsKey(ip)){ 
                count.put(ip,count.get(ip)+1); //存在，及原有的基础上加1
            }else{ 
                count.put(ip,1); //初始值为1
            }
            /*放入到application域中*/
            request.getServletContext().setAttribute("count",count);
            filterChain.doFilter(request, servletResponse); //放行
        }
    
        @Override
        public void destroy() { 
    
        }
    }