image.jsp------------------------------生成随机验证码图片的Jsp页面
<%@ page contentTy
PE="image/jpeg" import="java.awt.*,
java.awt.image.*,java.util.*,javax.imag
eio.*" %>
<%!
Color getRandColor(int
fc,int bc)
{
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);
}
%>
<%
out.clear();//这句针对resin
服务器，如果是tomacat可以不要这句
response.setHeader("
PRagma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("E
xpires", 0);
int width=60, height=20;
Buffe
redImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
Random random = new Random();
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height);
g.setFont(new Font("Times New
roman",Font.PL
aiN,18));
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);
}
String sRand="";
for (int i=0;i<4;i++){
String rand=String.valueOf(random.nextInt(10));
sRand+=rand;
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
g.drawString(rand,13*i+6,16);
}
// 将认证码存入SESSION
session.
setattribute("rand",sRand);
g.dispose();
ImageIO.wr
ITe(image, "JPEG", response.getOutputStre
am());
%>
<%@ page contentType="text/ht
ML;charset=gbk" %>
<%@ page language="java" import="java.
SQL.*" errorPage="" %>
<html>
<head>
<
;meta http-equiv="Content
-type" content="text/html; charset=gb2312">
<title>用户登录</title>
<script language="javascript">
function loadimage(){
document.getElementById("randImage").src = "image.jsp?"+Math.random();
}
</script>
</head>
<body>
<table width="256" border="0" cellpadding="0" cellspacing="0">
<!--DWLayoutTable-->
<form action="validate.jsp" method="post" name="lo
ginForm">
<tr>
<td width="118" height="22" valign="middle" align="
center"><input type="text" name="rand" size="15"></td>
<td width="138" valign="middle" align="center"><
img alt="code
..." name="randImage" id="randImage" src="image.jsp" width="60" height="20" border="1" align="absmiddle"></td>
</tr>
<tr>
<td height="36" colspan="2" align="center" valign="middle"><a
href="javascript:loadimage();"><font class=pt95>看不清点我</font></a></td>
</tr>
<tr>
<td height="36" colspan="2" align="center" valign="middle"><input type="s
ubmit" name="login" value="提交"></td>
</tr>
</form>
</table>
</body>
</html>