Java生产图片验证码

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.log4j.Logger;

import com.ailk.bboss.constants.Constants;
import com.ailk.bboss.util.ImageCode;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

/**
 * 生成随机验证码
 */
public class ValidateCodeServlet extends HttpServlet {
	private static final long serialVersionUID = -2333646554274127541L;

	protected void service(HttpServletRequest req, HttpServletResponse response)
			throws ServletException, java.io.IOException {
		HttpSession session = req.getSession();
		ImageCode image = new ImageCode();
		// 将四位数字的验证码保存到Session中。

		// 禁止图像缓存。
		response.setHeader("Pragma", "no-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);
		response.setContentType("image/jpeg");

		// 将图像输出到Servlet输出流中。
		ServletOutputStream outStream = response.getOutputStream();
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(outStream);
		encoder.encode(image.creatImage());
		outStream.close();

		session.setAttribute(Constants.VALIDATE_CODE, image.getStrRand());

		Logger.getLogger(this.getClass()).info(
				"image code = " + image.getStrRand() + "  cc");
	}

}

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.util.Random;

public class ImageCode {
	private String strRand = "";

	public final Color[] defCols = { Color.WHITE, Color.BLACK };

	private static String[] CHARS = getChars();

	public final Font[] defFonts = { new Font("隶书", Font.BOLD, 18),
			new Font("宋体", Font.BOLD, 18), new Font("楷体", Font.BOLD, 18),
			new Font("黑体", Font.BOLD, 18), new Font("rom7", Font.BOLD, 18) };

	private Font getFont(int i) {
		Random random = new Random(new Double(Math.random() * 10000 * (i + 1))
				.longValue());
		int a = random.nextInt(defFonts.length);
		AffineTransform trans = new AffineTransform();
		trans.scale(1 + random.nextFloat() * 0.2,
				0.95 + random.nextFloat() * 0.65);
		return defFonts[a].deriveFont(trans);
	}

	public BufferedImage creatImage() {
		int width = 75, height = 20;
		BufferedImage image = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_RGB);
		Graphics g = image.getGraphics();

		Random random = new Random();
		g.setColor(new Color(202, 255, 255));
		g.fillRect(0, 0, width, height);

		String arr[] = CHARS;

		Random rm = new Random(new Double(Math.random() * 10000 * 59)
				.longValue());
		g.setColor(Color.BLACK);
		for (int i = 0; i < 4; i++) {
			String rand = arr[rm.nextInt(arr.length)];
			strRand += rand;
			g.setFont(getFont(i));
			if (i == 0)
				g.drawString(rand, 2 + random.nextInt(2), 20);
			else
				g.drawString(rand, 16 * i + 2 + random.nextInt(3), 20);
		}
		g.dispose();
		return image;
	}

	public String getStrRand() {
		return strRand;
	}

	public void setStrRand(String strRand) {
		this.strRand = strRand;
	}

	private static String[] getChars() {
		String[] chars = null;
		chars = new String[] { "2", "3", "4", "5", "6", "7", "8", "9", "A",
				"B", "D", "E", "F", "G", "H", "J", "K", "L", "M", "N", "P",
				"R", "S", "U", "V", "X", "Y", "Z" };
		return chars;
	}

}