验证码 jsp生成

<%@ page contentType="image/jpeg" import="java.awt.*,

java.awt.image.*,java.util.*,javax.imageio.*" %><%!

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();//????resin???????tomacat??????

out = pageContext.pushBody();

response.setHeader("Pragma","No-cache");

response.setHeader("Cache-Control","no-cache");

response.setDateHeader("Expires", 0);

int width=60, height=20;

BufferedImage 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.PLAIN,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);

}

// 后台获取生成的数据

session.setAttribute("rand",sRand);

g.dispose();

ImageIO.write(image, "JPEG", response.getOutputStream());

%>

	<p>

					<input type="text" id="ValidateCode" name="ValidateCode"

						class="code" value="验证码"	onFocus="javascript:if(this.value=='验证码')this.value='';">

					 

					<img src="data:image.jsp" title="点击重新获取验证码"

						style="cursor: hand; vertical-align: top"

						onclick="this.src='image.jsp?date='+new Date();" width="74px"

						height="28px" />

				</p>