image.jsp

java + sqlserver2000编写的一个网上购书系统,实现了一些基本的功能,但对于初学者来说这个系统已经足以起到帮助作用

<%@ 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);
	}%>
<%
	//???????
	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(new Color());
	//g.drawRect(0,0,width-1,height-1);

	// ????155???????????????????????
	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);
	}

	// ?????????(4???)
	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);
	}

	// ??????SESSION
	session.setAttribute("rand", sRand);

	// ????
	g.dispose();

	// ???????
	ImageIO.write(image, "JPEG", response.getOutputStream());
%>