JSP常用功能模块
calendar.jsp
<!-- author:wildfield -->
<%@ page language="java" import="java.util.*" %>
<%! String year;
String month;
%>
<% month=request.getParameter("month");
year =request.getParameter("year");
%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>日</title>
<script Language="javascript">
<!--
function changeMonth()
{
var mm="calendar.jsp?month="+document.sm.elements[0].selectedIndex+"&year="
+<%=year%>;
window.open(mm,"_self");
}
//-->
</script>
</head>
<%! String days[]; %>
<%
days=new String[42];
for(int i=0;i<42;i++)
{
days="";
}
%>
<%
Calendar thisMonth=Calendar.getInstance();
if(month!=null&&(!month.equals("null")))
thisMonth.set(Calendar.MONTH, Integer.parseInt(month) );
if(year!=null&&(!year.equals("null")))
thisMonth.set(Calendar.YEAR, Integer.parseInt(year) );
year=String.valueOf(thisMonth.get(Calendar.YEAR));
month=String.valueOf(thisMonth.get(Calendar.MONTH));
thisMonth.setFirstDayOfWeek(Calendar.SUNDAY);
thisMonth.set(Calendar.DAY_OF_MONTH,1);
int firstIndex=thisMonth.get(Calendar.DAY_OF_WEEK)-1;
int maxIndex=thisMonth.getActualMaximum(Calendar.DAY_OF_MONTH);
for(int i=0;i<maxIndex;i++)
{
days[firstIndex+i]=String.valueOf(i+1);
}
%>
<body>
<FORM name="sm" method="post" action="calendar.jsp">
<%=year%>年 <%=Integer.parseInt(month)+1%>月
<table border="0" width="168" height="81">
<div align=center>
<tr>
<th width="25" height="16" bgcolor="#FFFF00"><font color="red">日</font>
</th>
<th width="25" height="16" bgcolor="#FFFF00">一</th>
<th width="25" height="16" bgcolor="#FFFF00">二</th>
<th width="25" height="16" bgcolor="#FFFF00">三</th>
<th width="25" height="16" bgcolor="#FFFF00">四</th>
<th width="25" height="16" bgcolor="#FFFF00">五</th>
<th width="25" height="16" bgcolor="#FFFF00"><font color="green">六</font></th>
</tr>
<% for(int j=0;j<6;j++) { %>
<tr>
<% for(int i=j*7;i<(j+1)*7;i++) { %>
<td width="15%" height="16" bgcolor="#C0C0C0" valign="middle" align="center">
<a href="jump.jsp?year=<%=year%>&month=<%=Integer.parseInt(month)+1%>&date=<%=days[i]%>" target="main"><%=days[i]%></a></td>
<% } %>
</tr>
<% } %>
</div>
</table>
<table border="0" width="168" height="20">
<tr>
<td width=30%><select name="month" size="1" onchange="changeMonth()" >
<option value="0">一月</option>
<option value="1">二月</option>
<option value="2">三月</option>
<option value="3">四月</option>
<option value="4">五月</option>
<option value="5">六月</option>
<option value="6">七月</option>
<option value="7">八月</option>
<option value="8">九月</option>
<option value="9">十月</option>
<option value="10">十一月</option>
<option value="11">十二月</option>
</select></td>
<td width=28%><input type=text name="year" value=<%=year%> size=4 maxlength=4></td>
<td>年</td>
<td width=28%><input type=submit value="提交"></td>
</tr>
</table>
</FORM>
<script Language="javascript">
<!--
document.sm.month.options.selectedIndex=<%=month%>;
//-->
</script>
</body>
</html>
JSP生成彩色验证码程序
生成有4个随机数字和杂乱背景的图片，数字和背景颜色会改变，服务器端刷新（用history.go(-1)也会变）
产生验证码图片的文件image.jsp
<%@ page contentType="image/jpeg" import="java.awt.*,
java.awt.image.*,java.util.*,javax.imageio.*" %>
<%!
Color getRandColor(int fc,int bc){//给定范围获得随机颜色
Random random = new Random();
if(fc>255) fc=255;
if(bc>255) bc=255;
int r=fc+random.nextInt(bc-fc);
int g=fc+random.nextInt(bc-fc);
int b=fc+random.nextInt(bc-fc);
return new Color(r,g,b);
}
%>
<%
//设置页面不缓存
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
// 在内存中创建图象
int width=60, height=20;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.getGraphics();
//生成随机类
Random random = new Random();
// 设定背景色
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height);
//设定字体
g.setFont(new Font("Times New Roman",Font.PLAIN,18));
//画边框
//g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);
// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
g.setColor(getRandColor(160,200));
for (int i=0;i<155;i++)
{
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x,y,x+xl,y+yl);
}
// 取随机产生的认证码(4位数字)
String sRand="";
for (int i=0;i<4;i++){
String rand=String.valueOf(random.nextInt(10));
sRand+=rand;
// 将认证码显示到图象中
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt
(110)));
//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
g.drawString(rand,13*i+6,16);
}
// 将认证码存入SESSION
session.setAttribute("rand",sRand);
// 图象生效
g.dispose();
// 输出图象到页面
ImageIO.write(image, "JPEG", response.getOutputStream());
%>
使用验证码图片的文件a.jsp
<%@ page contentType="text/html;charset=gb2312" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>认证码输入页面</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">
<META HTTP-EQUIV="Expires" CONTENT="0">
</head>
<body>
<form method=post action="check.jsp">
<table>
<tr>
<td align=left>系统产生的认证码：</td>
<td><img border=0 src="image.jsp"></td>
</tr>
<tr>
<td align=left>输入上面的认证码：</td>
<td><input type=text name=rand maxlength=4 value=""></td>
</tr>
<tr>
<td colspan=2 align=center><input type=submit value="提交检测"></td>
</tr>
</form>
</body>
</html>
验证的页面check.jsp
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<html>
<head>
<title>认证码验证页面</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">
<META HTTP-EQUIV="Expires" CONTENT="0">
</head>
<body>
<%
String rand = (String)session.getAttribute("rand");
String input = request.getParameter("rand");
%>
系统产生的认证码为： <%= rand %><br>
您输入的认证码为： <%= input %><br>
<br>
<%
if (rand.equals(input)) {
%>
<font color=green>输入相同，认证成功！</font>
<%
} else {
%>
<font color=red>输入不同，认证失败！</font>
<%
}
%>
</body>
</html>