java web 验证码-数字不变形

controller代码：

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

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("randomCheckCode")
public class RandomCheckCodeController {

    // 验证码图片的宽度。
    private int width = 60;
    // 验证码图片的高度。
    private int height = 20;
    // 验证码字符个数
    private int codeCount = 4;
    // 字体高度
    private int fontHeight;
    //字体的x坐标
    private int x = 0;
    private int y = 0;
    private static Random random = new Random();
　　//去除0、1、i、l等容易混淆字符
    public static final String VERIFY_CODES = "23456789abcdefghjkmnprstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";

    private static Color getRandColor(int fc, int bc) {
        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);
    }

    /**
     * 初始化图片属性
     */
    public void init() {
        x = width / (codeCount );
        fontHeight = height - 2;
        y = height - 4;
    }
    @RequestMapping("generate")
    public void generateNumber(HttpServletRequest request,
            HttpServletResponse resp) {
            init();
        // 定义图像buffer
        BufferedImage buffImg = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        Graphics2D g = buffImg.createGraphics();
        // 填充背景色
//        g.setColor(getRandColor(200, 250));
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, width, height);
        // 创建字体，字体的大小应该根据图片的高度来定
        Font font = new Font("Fixedsys", Font.PLAIN, fontHeight);
        // 设置字体
        g.setFont(font);
        // 画一个边框
        g.setColor(Color.GRAY);
        g.drawRect(0, 0, width - 1, height - 1);
        // 随机产生160条干扰线，使图象中的验证码不易被其它程序探测到
        g.setColor(Color.BLACK);
        for (int i = 0; i < 10; 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);
        }
        // randomCode用于保存随机产生的验证码，以便用户登录后进行验证
        StringBuffer randomCode = new StringBuffer();
        int red = 0, green = 0, blue = 0;
        // 随机产生codeCount数字的验证码。
        for (int i = 0; i < codeCount; i++) {
            // 得到随机产生的验证码数字
            char ch = VERIFY_CODES.charAt(random.nextInt(VERIFY_CODES.length()));
            // 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同
            red = random.nextInt(255);
            green = random.nextInt(255);
            blue = random.nextInt(255);
            // 用随机产生的颜色将验证码绘制到图像中
            g.setColor(new Color(red, green, blue));
            g.drawString(String.valueOf(ch),  i*x+1, y);
            // 将产生的四个随机数组合在一起
            randomCode.append(ch);
        }
        // 将四位数字的验证码保存到Session中
        HttpSession session = request.getSession();
        session.setAttribute("validateCode", randomCode.toString());
        // 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
        try {
            ServletOutputStream sos = resp.getOutputStream();
            ImageIO.write(buffImg, "jpeg", resp.getOutputStream());
            sos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

jsp代码：

<img src="${ctx }/randomCheckCode/generate1?t=1" id="CreateCheckCode" align="middle" onclick="reloadPic()">

<script type="text/javascript">
function reloadPic() {  
    document.getElementById("checkCode").src = document.getElementById("checkCode").src + "1";
}  
</script>

效果：