package com.code;import java.awt.Color;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.PrintWriter;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class ImageServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {BufferedImage bImage=new BufferedImage(68, 22, BufferedImage.TYPE_INT_RGB);//画图Graphics graphics=bImage.getGraphics();Color color=new Color(220,150,130);graphics.setColor(color);//给图片画个框graphics.fillRect(0, 0, 78, 27);/** * 在图片中显示的内容 * 字母和数字的组合 */char[] ch="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();//随机获取里面的内容Random random=new Random();int len=ch.length,index;StringBuffer sb=new StringBuffer();for(int i=0;i<4;i++){index=random.nextInt(len);graphics.setColor(new Color(random.nextInt(88),random.nextInt(188),random.nextInt(255)));graphics.drawString(ch[index]+"",(i*15)+3, 18);sb.append(ch[index]);}//将验证码保存到session为以后比较使用request.getSession().setAttribute("piccode", sb.toString());ImageIO.write(bImage, "JPG", response.getOutputStream());}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {}}ImageServlet类写完之后，，需要在web.xml里面配置该servlet
不做任何解释。没有人明白，
