该猜数字游戏主要用到了servlet方面的session，HttpServletResponse类中的sendRedirect()方法。
step1，客户访问或刷新getNumber.jsp页面时，随机给用户分配一个1-100之间的数字，将该数字存放到客户的session中。
<%@ page language="java" import="java.util.*"
contentType="text/html;charset=utf-8"%>
<html>
<head>
</head>
<body>
<%
String message=(String)session.getAttribute("message");
%>
<form action="HandleGuess" methods="post">
<input type="text" name="guessnumber" size=8>
<%=message %>
<input type="submit" value="提交">
</form>
<form action="getNumber.jsp" method="post">
<input type="submit" value="重新得到新的随机数">
</form>
</body>
</html>
step2，然后用户超廉价到inputNumber.jsp页面上，用户输入自己的猜测，并提交给HandleGuess类负责创建。
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"
contentType="text/html;Charset=utf-8"%>
<html>
<head>
</head>
<body>
<% session.setAttribute("message", "请您猜数");
// HttpSession session =request.getSession(true);
int randomNumber=(int)(Math.random()*100)+1;//获取一个随机数
session.setAttribute("saveNumber",new Integer(randomNumber));
%>
<p>访问或刷新该页面可以随机跌倒一个1，到100之间的数字
<br>单击下面链接可以访问去猜数字
<a href="inputNumber.jsp">去猜数字</a>
</body>
</html>
step3,该servlet类为：
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class HandleGuess extends HttpServlet {
public void doPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
PrintWriter out=response.getWriter();
//获取客户猜测提交的数
int guessNumber=Integer.parseInt(request.getParameter("guessnumber"));
//获取客户的会话对象
HttpSession session=request.getSession();
Integer integer=(Integer)session.getAttribute("saveNumber");
int realNumber=integer.intValue();
System.out.println(realNumber);
System.out.println(guessNumber);
if(guessNumber>realNumber){
session.setAttribute("message", "您猜大了");
System.out.println("您猜大了---no");
response.sendRedirect("inputNumber.jsp");
}
else if(guessNumber<realNumber){
session.setAttribute("message", "您猜小了");
System.out.println("您猜小了---no");
response.sendRedirect("inputNumber.jsp");
}
else{
session.setAttribute("message", "您猜对了");
System.out.println("您猜对了");
response.sendRedirect("inputNumber.jsp");
}
}
public void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
doPost(request,response);
}
}
step4，web.xml配置，省略。