使用过滤器监控网站流量

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过滤器实现类FilterNum.java

public class FilterNum extends HttpServlet implements Filter {
private static int num=0;//定义全局变量
	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain)
			throws IOException, ServletException {
		this.num++;
		request.setAttribute("num", String.valueOf(num));
		filterChain.doFilter(request, response);
	}

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		
	}

}

index.jsp页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<table width="300" height="100" border="0" cellpadding="0" cellspacing="0">
	<tr align="center" bgcolor="lightblue"><Td>目前在线访问流量是：</Td></tr>
	<tr align="center">
		<td><%=request.getAttribute("num") %>人访问过</td>
	</tr>
</table>
</body>
</html>

web.xml文件配置

 <filter>
  	<filter-name>filterNum</filter-name>
  	<filter-class>com.cn.zj.Filter.FilterNum</filter-class>
  </filter>
  <filter-mapping>
  	<filter-name>filterNum</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>

使用过滤器监控网站流量

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