authimg.java

来自「整合了struts2+spring+hibernate的一个登陆/注册的小dem」· Java 代码 · 共 102 行

package gym.web;

import javax.servlet.http.HttpServlet;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.awt.*;
import java.awt.image.*;
import java.util.*;
import javax.imageio.*;

public class AuthImg extends HttpServlet {

	private Font mFont = new Font("Arial Black", Font.PLAIN, 16);

	public void init() throws ServletException {
		super.init();
	}

	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);
	}

	public void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);
		response.setContentType("image/jpeg");

		int width = 100, height = 18;
		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(1, 1, width - 1, height - 1);
		g.setColor(new Color(102, 102, 102));
		g.drawRect(0, 0, width - 1, height - 1);
		g.setFont(mFont);

		g.setColor(getRandColor(160, 200));
		for (int i = 0; i < 155; i++) {
			int x = random.nextInt(width - 1);
			int y = random.nextInt(height - 1);
			int xl = random.nextInt(6) + 1;
			int yl = random.nextInt(12) + 1;
			g.drawLine(x, y, x + xl, y + yl);
		}
		for (int i = 0; i < 70; i++) {
			int x = random.nextInt(width - 1);
			int y = random.nextInt(height - 1);
			int xl = random.nextInt(12) + 1;
			int yl = random.nextInt(6) + 1;
			g.drawLine(x, y, x - xl, y - yl);
		}

		String sRand = "";
		for (int i = 0; i < 6; i++) {
			String tmp = getRandomChar();
			sRand += tmp;
			g.setColor(new Color(20 + random.nextInt(110), 20 + random
					.nextInt(110), 20 + random.nextInt(110)));
			g.drawString(tmp, 15 * i + 10, 15);
		}

		HttpSession session = request.getSession(true);
		session.setAttribute("rand", sRand);
		g.dispose();
		ImageIO.write(image, "JPEG", response.getOutputStream());
	}

	private String getRandomChar() {
		int rand = (int) Math.round(Math.random() * 2);
		long itmp = 0;
		char ctmp = '\u0000';
		switch (rand) {
		case 1:
			itmp = Math.round(Math.random() * 25 + 65);
			ctmp = (char) itmp;
			return String.valueOf(ctmp);
		case 2:
			itmp = Math.round(Math.random() * 25 + 97);
			ctmp = (char) itmp;
			return String.valueOf(ctmp);
		default:
			itmp = Math.round(Math.random() * 9);
			return String.valueOf(itmp);
		}
	}

}