站点的网站计数器的操作

<%@ page import="java.math.BigInteger" %>
<%@ page import="java.io.File" %>
<%@ page import="java.util.Scanner" %>
<%@ page import="java.io.FileInputStream" %>
<%@ page import="java.io.PrintStream" %>
<%@ page import="java.io.FileOutputStream" %>
<%@ page import="java.util.zip.InflaterOutputStream" %><%--
  Created by IntelliJ IDEA.
  User: ming
  Date: 19-3-12
  Time: 下午10:25
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%
    // 定义全局变量
    BigInteger count = null;
%>
<%!
    // 获取计数器
    public BigInteger load(File file){
        BigInteger count = null;
        try{
            // 若文件存在则读取
            if(file.exists()){
                Scanner scanner = null;
                // 获取到文件的输入流
                scanner = new Scanner(new FileInputStream(file));
                // 对计数器内容进行加1
                if(scanner.hasNext()){
                    count = new BigInteger(scanner.next());
                }
                scanner.close();
            }else{
                count = new BigInteger("0");
                save(file, count);
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        return count;
    }
    // 计数文件保存回文件
    public void save(File file, BigInteger count){
        try{
            PrintStream printStream = null;
            printStream = new PrintStream(new FileOutputStream(file));
            // 流中输入对象
            printStream.println(count);
            printStream.close();
        }catch (Exception e){
            e.printStackTrace();
        }
    }
%>
<%
    // 获取文件路径
    String fileName = this.getServletContext().getRealPath("/") + "count.txt";
    // 定义file对象
    File file = new File(fileName);
    // 进行加
    if(session.isNew()) {
        synchronized (this) {
            count = load(file);
            System.out.println(count);
            count = count.add(new BigInteger("1"));
            save(file, count);
        }
    }
%>
您是第<%=count%>
</body>
</html>

web映射

文件保存在WEB-INF文件夹下,永远无法访问,此时,需要修改/WEB-INF/web.xml文件即可,达到映射的目的
修改xml文件如下

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <servlet>
    <servlet-name>he</servlet-name>
    <jsp-file>/WEB-INF/he.jsp</jsp-file>
  </servlet>
  <servlet-mapping>
    <servlet-name>he</servlet-name>
    <url-pattern>/hello</url-pattern>
  </servlet-mapping>
</web-app>


直接更新,但不重启,发现不能加载.
此时.即Tomcat需要重写配置属性
此时访问
http://localhost:8080/hello
即可访问

config

config用于获得