manage/uas_mall/WebContent/jsps/common/vcode.jsp

<%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="UTF-8"%>
<%!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);
	}
char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
	    'X', 'Y', '3', '4', '5', '6', '7', '8', '9' };	
%>
<%
	response.setHeader("Pragma", "No-cache");
	response.setHeader("Cache-Control", "no-cache");
	response.setDateHeader("Expires", 0);
	int width = 80, 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.BOLD, 18));

	g.setColor(new Color(0, 0, 0));
	g.drawRect(0, 0, width - 1, height - 1);

	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(codeSequence[random.nextInt(30)]);
		sRand += rand;
		g.setColor(new Color(random.nextInt(80), random.nextInt(80), random.nextInt(80)));
		g.drawString(rand, 15 * i + 10, 16);
	}
	session.setAttribute("validcode", sRand);
	g.dispose();

	ServletOutputStream sos = response.getOutputStream();
	ImageIO.write(image, "jpeg", sos);
	sos.flush();
	sos.close();
	sos = null;
	response.flushBuffer();
	out.clear();
	out = pageContext.pushBody();
%>