使用Servlet绘制动态的数字图片

以下是web.xml的配置

    <?xml version="1.0" encoding="UTF-8"?>        <web-app version="2.5"             xmlns="http://java.sun.com/xml/ns/javaee"             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"             xsi:schemaLocation="http://java.sun.com/xml/ns/javaee             http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">          <servlet>            <servlet-name>GenerateImageServlet</servlet-name>            <servlet-class>com.jadyer.servlet.GenerateImageServlet</servlet-class>          </servlet>                    <servlet-mapping>            <servlet-name>GenerateImageServlet</servlet-name>            <url-pattern>/servlet/image</url-pattern>          </servlet-mapping>        </web-app>  

    <%@ page language="java" pageEncoding="UTF-8"%>        <%response.sendRedirect(request.getContextPath()+"/servlet/image");%>  

    package com.jadyer.servlet;        import java.awt.Color;        import java.awt.Font;        import java.awt.Graphics2D;        import java.awt.image.BufferedImage;        import java.io.IOException;        import java.io.OutputStream;        import java.util.Random;        import javax.imageio.ImageIO;        import javax.imageio.stream.ImageOutputStream;        import javax.servlet.http.HttpServlet;        import javax.servlet.http.HttpServletRequest;        import javax.servlet.http.HttpServletResponse;                /**        * 绘制随机数字图片的Servlet        */        public class GenerateImageServlet extends HttpServlet {            private static final long serialVersionUID = 760480418450678827L;                        // 产生的图像的宽度，单位为像素            private final static int WIDTH = 260;                        // 产生的图像的高度，单位为像素            private final static int HEIGHT = 60;                        public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {                // 设置输出的内容的类型为JPEG图像                response.setContentType("image/jpeg");                OutputStream os = response.getOutputStream();                createImage(os);                os.close();            }                        /**            * 绘制输出整个图形            */            public void createImage(OutputStream os) throws IOException {                // 创建一个BufferedIamge对象                BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);                                // 获取的Graphics2D对象，通过这个对象完成绘图                Graphics2D g = image.createGraphics();                                  // 绘制背景图                g.setColor(Color.white);                g.fillRect(0, 0, WIDTH, HEIGHT);                                    // 画边框                g.setColor(Color.black);                g.drawRect(0, 0, WIDTH - 1, HEIGHT - 1);                                // 设定字体                g.setFont(new Font("Times New Roman", Font.PLAIN, 60));                                // 生成随机类                Random random = new Random();                                // 取随机产生的6位数字                for (int i = 0; i < 6; i++) {                    String rand = String.valueOf(random.nextInt(10));                    // 将随机产生的数字显示到图象中                    g.drawString(rand, 40 * i + 20, 50);                }                                // 生成图像的输出流                ImageOutputStream ios = ImageIO.createImageOutputStream(os);                ImageIO.write(image, "jpeg", ios);                ios.close();            }        }