.jsp和servlet验证码

packageCls;importjava.awt.Color;importjava.awt.Font;importjava.awt.Graphics;importjava.awt.Graphics2D;importjava.awt.image.BufferedImage;importjava.io.IOException;importjava.util.Random;importjavax.servlet.ServletOutputStream;importjavax.servlet.http.HttpServlet;importjavax.se