SSM框架下验证码密码制作过程，密码加密操作代码(一)

这是验证码的生成过程（servlet）

package com.dagewang.web;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.util.Random;

import javax.imageio.ImageIO;
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;

public class ValidateCodeServlet extends HttpServlet {

	// 验证码图片的宽度。      
	private int width = 60;

	// 验证码图片的高度。      
	private int height = 20;

	char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
			'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
			'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };

	/**    
	 * 初始化验证图片属性    
	 */
	public void init() throws ServletException {
		// 从web.xml中获取初始信息      
		// 宽度      
		String strWidth = this.getInitParameter("width");
		// 高度      
		String strHeight = this.getInitParameter("height");
		// 字符个数      
		String strCodeCount = this.getInitParameter("codeCount");

		// 将配置的信息转换成数值      
		try {
			if (strWidth != null && strWidth.length() != 0) {
				width = Integer.parseInt(strWidth);
			}
			if (strHeight != null && strHeight.length() != 0) {
				height = Integer.parseInt(strHeight);
			}			
		} catch (NumberFormatException e) {
		}
	}

	protected void service(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, java.io.IOException {


		 // 在内存中创建图象		
		BufferedImage image = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_RGB);

		// 获取图形上下文
		Graphics g = image.getGraphics();

		// 生成随机类
		Random random = new Random();

		// 设定背景色
		g.setColor(getRandColor(200, 250));
		g.fillRect(0, 0, width, height);

		// 设定字体
		g.setFont(new Font("Times New Roman", Font.PLAIN, 18));

		// 画边框
		g.setColor(Color.BLACK);
		g.drawRect(0,0,width-1,height-1);

		// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
		g.setColor(getRandColor(170, 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(36)]);
			sRand += rand;
			// 将认证码显示到图象中
			g.setColor(new Color(20 + random.nextInt(110), 20 + random
					.nextInt(110), 20 + random.nextInt(110)));// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
			g.drawString(rand, 13 * i + 6, 16);
		}
		// 图象生效
		g.dispose();
		// 将四位数字的验证码保存到Session中。
		HttpSession session = req.getSession();
		session.setAttribute("validateCode", sRand);

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

		resp.setContentType("image/jpeg");

		// 将图像输出到Servlet输出流中。      
		ServletOutputStream sos = resp.getOutputStream();
		ImageIO.write(image, "jpeg", sos);
		sos.close();
	}
	
	 public Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
		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);
	}

}

这是密码加密的代码 （vo类）

package com.dahewang.vo;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * String Utility Class This is used to encode passwords programmatically
 */
public class StringUtil {

	private final static Log log = LogFactory.getLog(StringUtil.class);

	private static MessageDigest digest = null;

	/**  
	 * 对字符串进行MD5加密  
	 * @param data  
	 * @return  
	 */
	public static String encode(String data) {
		if (digest == null)
			try {
				digest = MessageDigest.getInstance("MD5");
			} catch (NoSuchAlgorithmException nsae) {
				log.error("Failed to load the MD5 MessageDigest."
						+ " We will be unable to function normally.");
				nsae.printStackTrace();
			}
		digest.update(data.getBytes());
		return encodeHex(digest.digest());
	}

	private static String encodeHex(byte bytes[]) {
		StringBuffer buf = new StringBuffer(bytes.length * 2);
		for (int i = 0; i < bytes.length; i++) {
			if ((bytes[i] & 0xff) < 16)
				buf.append("0");
			buf.append(Long.toString(bytes[i] & 0xff, 16));
		}
		return buf.toString().toUpperCase();
	}
}