首先写两个jsp文件
info.jsp
<body>
<%
HashMap<String, Integer> scoreMap = (HashMap<String, Integer>)application.getAttribute("scoreMap");
if(scoreMap == null){
scoreMap = new HashMap<String, Integer>();
}
String ip = request.getRemoteAddr();
Integer score = scoreMap.get(ip);
if (score == null) {
score = new Random().nextInt(7) - 1;
scoreMap.put(ip, score);
}
System.out.println(ip + ":" + score);
application.setAttribute("scoreMap",scoreMap);
request.setAttribute("score", score);
request.getRequestDispatcher("draw.jsp").forward(request, response);
%>
</body>
</html>
draw.jsp
<body>
<%
HashMap<String, Integer> scoreMap = (HashMap<String, Integer>) application
.getAttribute("scoreMap");
Integer score = (Integer) request.getAttribute("score");
String ip = (String) request.getAttribute("ip");
String msg = "";
if (score != null) {
switch (score) {
case -1:
msg = "祝您下次好运";
break;
case 0:
msg = "真可惜，差一点就中奖了";
break;
case 1:
msg = "恭喜您中了五等奖";
break;
case 2:
msg = "恭喜您中了四等奖";
break;
case 3:
msg = "恭喜您中了三等奖";
break;
case 4:
msg = "恭喜您中了二等奖";
break;
case 5:
msg = "恭喜您中了一等奖";
break;
}
}
%>
<form action="info.jsp" method="post">
<input type="submit" value="点击抽奖吧" />
</form>
<%=msg%>
</body>
</html>
在两个jsp中，draw.jsp中为页面效果，在点击抽奖之后，draw.jsp会向info.jsp发送请求info.jsp会生成一个随机数传给draw.jsp，draw.jsp会根据传回的随机数决定输出内容
下面为代码效果
draw.jsp页面的效果
draw.jsp页面点击之后的效果
