验证码问题

Question

下面是我的基于Servlet的验证码程序，我想在这个验证码上增加几条横杠之类的干扰条，应该怎样加？
import java.util.Random;
import java.awt.*;
import java.awt.Image.*;
import java.awt.image.BufferedImage;
import javax.imageio.*;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;public class ImgServlet extends HttpServlet{
protected void doPost(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException {

doGet(request,response);

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

OutputStream out = response.getOutputStream();
int width = 80,height = 20;
BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

Graphics g = image.getGraphics();

Random random = new Random();

g.fillRect(0,0,width,height);
g.setFont(new Font("Times New Roman",Font.ITALIC,18));
// 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,20*i+6,16);
}
g.dispose();
ImageIO.write(image,"JPEG",out);


}
}