java防刷新网站计数器(BigInteger)

1:计数器的类;

package com;

import java.io.*;
import java.util.*;
import java.math.*;
/**
 * 防刷新的网站计数器;
 * 使用BigInteger来存贮;
 * @author clplain;
 *
 */
public class count {
 BigInteger count=null;
 public BigInteger load(File file) throws Exception{
  if(file.exists()){
  Scanner scn=new Scanner(new FileInputStream(file));
  if(scn.hasNext()){
   count=new BigInteger(scn.next());
  }
  scn.close();
  }else{
    count=new BigInteger("0");
    save(file,count);
  }
  return count;
 }
 
 public void save(File file,BigInteger count)throws Exception{
  PrintStream ps=null;
  ps=new PrintStream(new FileOutputStream(file));
  ps.println(count);
  ps.close();
 }
}
2:计数器页面;

<%@page contentType="text/html;charset=gb2312"%>
<%@page import ="java.math.*"%>
<%@page import="java.util.*"%>
<%@page import="java.io.*" %>
<%@page import="com.count"%>
<html>
<head>
<title>网站计数器</title>
<style type="text/css">
<!--
body {
 background-color: #99FFFF;
}
-->
</style></head>
<%!BigInteger count=null; %>
<%String path=this.getServletContext().getRealPath("/")+"count.txt"; %>
<%
count t=new count();
File file=new File(path);
if(session.isNew()){
 synchronized(this){
 count=t.load(file);
 count=count.add(new BigInteger("1"));
 t.save(file,count);
 }
}
%>
<body topmargin="50">
<table width="401" height="30" border="1" align="right">
  <tr>
    <td width="391" height="24" align="center"><strong>您是第<%=count==null?0:count%>位访问本站的用户</strong></td>
  </tr>
</table>
</body>
</html>

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