代码如下：
文件：count.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@page import="java.io.*" %>
<%@page import="java.util.*" %>
<%@page import="java.math.*" %>
<!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>
<%!
BigInteger count=null;
%>
<%!
public BigInteger load(File file)
{
BigInteger count=null;
try{
if(file.exists()){
Scanner scan=null;
scan=new Scanner(new FileInputStream(file));
if(scan.hasNext()){
count=new BigInteger(scan.next());
}
scan.close();
}else{
count =new BigInteger("0");
save(file,count);
}
}catch(Exception e){
e.printStackTrace();
}
return count;
}
public void save(File file,BigInteger count){
try{
PrintStream ps=null;
ps=new PrintStream(new FileOutputStream(file));
ps.println(count);
ps.close();
}catch(Exception e)
{
e.printStackTrace();
}
}
%>
<%
//文件路径：D:\JAVA\workplace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\Text
String fileName=this.getServletContext().getRealPath("/")+"count.txt";
File file=new File(fileName);
if(session.isNew()){
synchronized(this){
count = load(file);
count=count.add(new BigInteger("1"));
save(file,count);
}
}
%>
<h2>您是第<%=count==null?0:count %>位访客！！</h2>
</body>
</html>
