页面定时刷新或者自动跳转
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'ch03_12.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
当前时间是:<%=new Date().toLocaleString()%><br>
<hr>
<%response.setHeader("refresh","1")%>
</body>
</html>
创建及获取客户的会话信息
<body>
<hr>
session的创建时间是<%=new Date(session.getCreationTime()) %><br>
session的ID号:<%=session.getId() %><br>
客户最近一次访问的时间是:
<%=new java.sql.Time(session.getLastAccessedTime()) %><br>
两次请求时间间隔多长session将被取消(ms)
<%=session.getMaxInactiveInterval() %><br>
是否新创建的session<%=session.isNew()?"是":"否"%>
<hr>
</body>
案例——统计网站访问人数
<body>
<%!Integer YourNumber=new Integer(0);%>
<%
if(session.isNew()){//如果是一个新的会话
Integer number=(Integer)application.getAttribute("Count");
if(number==null)//如果是第一个访问本站
number=new Integer(1);
else
number=new Integer(number.intValue()+1);
application.setAttribute("Count", number);
YourNumber=(Integer)application.getAttribute("Count");
}
%>
欢迎访问本站,您是第<%=YourNumber%>个访问用户。
</body>
Out对象
<body>
利用out对象输出的页面信息:<br>
<hr>
<%
out.print("张小黑<br/>嘿嘿嘿");
out.print("<br/>用户名或密码不正确,请重新 <a href='http://www.baidu.com'> <font size='15' color='red'>登陆</font></a>");
out.print("<br><a href='javascript:history.back()'>后退</a>.......");
%>
JSP应用程序设计综合实例
网上答题及自动测评系统
ch03_17_1.jsp
<body>
<form action="ch03_17_2.jsp" method="post">
一 2+3=?<br>
<input type="radio" name="r1" value="2" checked="checked">2
<input type="radio" name="r1" value="3">3
<input type="radio" name="r1" value="4">4
<input type="radio" name="r1" value="5">5<br>
二 下列哪些是偶数?<br>
<input type="checkbox" name="c1" value="2" checked="checked">2
<input type="checkbox" name="c1" value="3">3
<input type="checkbox" name="c1" value="4">4
<input type="checkbox" name="c1" value="5">5<br>
三 下列哪些是动态网页?<br>
<select size="4" name="list1" multiple="multiple">
<option value="asp">ASP</option>
<option value="php">PHP</option>
<option value="htm">HTM</option>
<option value="jsp">JSP</option>
<option value="xyz" selected="selected">XYZ</option>
</select><br>
四 下列组件那个是服务器端的?<br>
<select size="1" name="list5">
<option value="jsp">JSP</option>
<option value="servlet"> SERVLET</option>
<option value="java">JAVA</option>
<option value="jdbc">JDBC</option>
</select><br>
五 在服务器端用来接受用户请求的对象是:
<input type="text" size="20" name="text1"><br>
<div align="left">
<blockquote>
<input type="submit" value="提交" name="button1">
<input type="reset" value="重置" name="button2">
</blockquote>
</div>
</form>
</body>
ch03_17_2.jsp
<body>
<%
String s1=request.getParameter("r1");
if(s1!=null){
out.println("一 解答为:2+3="+s1+" ");
if(s1.equals("5"))
out.println("正确!"+"<br>");
else
out.println("错误!"+"<br>");
}
else
out.println("一 没有解答!");
out.println("--------------------------------<br>");
String[] s21=request.getParameterValues("c1");
if(s21!=null){
out.println("二 解答:偶数有:");
for(int i=0;i<s21.length;++i){
out.println(s21[i]+" ");
}
if(s21.length==2&&s21[0].equals("2")&&s21[1].equals("4"))
out.println("正确! "+"<br>");
else
out.println("错误!"+"<br>");
}
else
out.println("二 没有解答!");
out.println("--------------------------------<br>");
String[] s31=request.getParameterValues("list1");
if(s31!=null){
out.println("三 解答为:动态网页有:");
for(int i=0;i<s31.length;++i){
out.println(s31[i]+" ");
}
if(s31.length==3&&s31[0].equals("asp")&&s31[1].equals("php")
&&s31[2].equals("jsp"))
out.println("正确!"+"<br>");
else
out.println("错误!"+"<br>");
}
else
out.println("三 没有解答! ");
out.println("--------------------------------<br>");
String s4=request.getParameter("list5");
if(s4!=null){
out.println("四 解答为:服务器端的组件有:");
out.println(s4+" ");
if(s4!=null&&s4.equals("servlet"))
out.println("正确!"+"<br>");
else
out.println("错误!"+"<br>");
}
else
out.println("四 没有正确答案!");
out.println("--------------------------------<br>");
String s5=request.getParameter("text1");
if(s5!=null){
out.println("五 解答为:");
out.println(s5+" ");
if(s5!=null&&s5.equals("request"))
out.println("正确!"+"<br>");
else
out.println("错误!"+"<br>");
}
else
out.println("五 没有解答!");
out.println("--------------------------------<br>");
%>
</body>
设计简单的购物车应用案例
ch03_17_1.jsp
<body>
<%
request.setCharacterEncoding("UTF-8");
if(request.getParameter("c1")!=null)
session.setAttribute("s1",request.getParameter("c1"));
if(request.getParameter("c2")!=null)
session.setAttribute("s2",request.getParameter("c2"));
if(request.getParameter("c3")!=null)
session.setAttribute("s3",request.getParameter("c3"));
%>
各类肉大甩卖一律十块<br>
<form method="post" action="ch03_18_1.jsp">
<p>
<input type="checkbox" name="c1" value="猪肉">猪肉
<input type="checkbox" name="c2" value="牛肉">牛肉
<input type="checkbox" name="c3" value="羊肉">羊肉
</p>
<p>
<input type="submit" value="提交" name="B1">
<a href="ch03_17_2.jsp">买点别的</a>
<a href="ch03_17_3.jsp">查看购物车</a>
</p>
</form>
</body>
ch03_17_2.jsp
<body>
<%
request.setCharacterEncoding("UTF-8");
if(request.getParameter("b1")!=null)
session.setAttribute("s4",request.getParameter("b1"));
if(request.getParameter("b2")!=null)
session.setAttribute("s5",request.getParameter("b2"));
if(request.getParameter("b3")!=null)
session.setAttribute("s6",request.getParameter("b3"));
%>
各种球大甩卖,一律八块:<br>
<form method="post" action="ch03_18_2.jsp">
<p>
<input type="checkbox" name="b1" value="篮球">篮球
<input type="checkbox" name="b2" value="足球">足球
<input type="checkbox" name="b3" value="排球">排球
</p>
<p>
<input type="submit" value="提交" name="x1">
<a href="ch03_17_1.jsp">买点别的</a>
<a href="ch03_17_3.jsp">查看购物车</a>
</p>
</form>
</body>
ch03_17_3.jsp
<body>
你选择的结果是:<br>
<%
request.setCharacterEncoding("UTF-8");
String str="";
if(session.getAttribute("s1")!=null){
str=(String)session.getAttribute("s1");
out.println(str+"<br>");
}
if(session.getAttribute("s2")!=null){
str=(String)session.getAttribute("s2");
out.println(str+"<br>");
}
if(session.getAttribute("s3")!=null){
str=(String)session.getAttribute("s3");
out.println(str+"<br>");
}
if(session.getAttribute("s4")!=null){
str=(String)session.getAttribute("s4");
out.println(str+"<br>");
}
if(session.getAttribute("s5")!=null){
str=(String)session.getAttribute("s5");
out.println(str+"<br>");
}
if(session.getAttribute("s6")!=null){
str=(String)session.getAttribute("s6");
out.println(str+"<br>");
}
%>
</body>