一個可以防止刷新的JSP計數(shù)器

2020-07-27 21:56:13

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供稿：網(wǎng)友

<%@ page contentType="text/html;charset=gb2312" %>

<%-- 以前學ASP時,用ASP做防止刷新的計數(shù)器很簡單,以下是一個用JSP做的計數(shù)器--%>
<html>
<head>
<title>jsp計數(shù)器</title>
</head>
<body>
<%@ page import="java.io.*" %>
<%
//out.println(request.getHeader("Cookie"));
String currentRecord = null;//保存文本的變量
BufferedReader file; //BufferedReader對象，用于讀取文件數(shù)據(jù)
String nameOfTextFile = "count.txt";

//讀取
file = new BufferedReader(new FileReader(nameOfTextFile));
String readStr =null;
int writeStr =0; //如果計數(shù)文本中的計數(shù)值為空則讓它顯示時變成1并寫入
try
{ readStr = file.readLine(); }
catch (IOException e)
{ System.out.println("讀取數(shù)據(jù)錯誤."); }
if (readStr == null) readStr = "沒有任何記錄";

//判斷cookie,第一次登陸時加1,刷新時不累計計數(shù)
else if (request.getHeader("Cookie")==null)
{ writeStr = Integer.parseInt(readStr)+1;}
else
{ writeStr = Integer.parseInt(readStr);}

//寫入時控制因為刷新引起的重復計數(shù)
if (request.getHeader("Cookie")==null)
{
try {
PrintWriter pw = new PrintWriter(new FileOutputStream(nameOfTextFile));
pw.println(writeStr);
pw.close();}
catch(IOException e) {
out.println(e.getMessage());}
}
%>
您是CNJSP的第<%=writeStr%>位客人。
</body>
</html>

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