验证码

image.jsp页面：

<%@ page contentType="image/JPEG"

import="java.awt.*,java.awt.image.*,java.util.*,java.io.*,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();

response.setHeader("contentType", "image/JPEG");

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

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

response.setDateHeader("Expires", 0);

int width = 70, 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(new Color());

//g.drawRect(0,0,width-1,height-1);

Color wColor = getRandColor(160, 200);

g.setColor(wColor);

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, 15 * i + 6, 15);

}

session.setAttribute("rand", sRand);

g.dispose();

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

%>

使用<img src="<%=request.getContextPath() %>/image.jsp"  />