package com.xmyself.model; import java.awt.image.BufferedImage; public class VerifyCode {    PRivate String code;    private BufferedImage image;     public VerifyCode(String code, BufferedImage image) {        this.code = code;        this.image = image;    }     public String getCode() {        return code;    }     public void setCode(String code) {        this.code = code;    }     public BufferedImage getImage() {        return image;    }     public void setImage(BufferedImage image) {        this.image = image;    }}
生成隨機驗證碼和圖片的類VerifyCodeFactory.java，這并不是靜態工廠，只是一個名稱而已
package com.xmyself.factory; import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.util.Random; import com.xmyself.model.VerifyCode; public class VerifyCodeFactory {    public static VerifyCode create() {        String code = getRandomString(4);        return new VerifyCode(code, drawImage(code));    }         private static String getRandomString(int length) {        if (length < 0 || length > 8) length = 4;        String scope = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";        StringBuffer code = new StringBuffer();        Random random = new Random();        for (int i = 0; i < length; i++) {            code.append(scope.charAt(random.nextInt(scope.length() - 1)));        }        return code.toString();    }         private static Color getRandomColor() {        Random random = new Random();        int r = random.nextInt(255);        int g = random.nextInt(255);        int b = random.nextInt(255);        return new Color(r, g, b);    }         private static BufferedImage drawImage(String code) {        int width = 80;        int height = 34;        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);        //畫邊框和背景        Graphics brush = image.getGraphics();        brush.setColor(getRandomColor());        brush.fillRect(0, 0, width - 1, height - 1);        brush.drawRect(0, 0, width - 1, height - 1);        //畫驗證碼        brush.setColor(getRandomColor());        brush.setFont(new Font("Times New Roman", Font.ITALIC, 28));        brush.drawString(code, 7, 22);         brush.dispose();        return image;    }}創建servlet類VerifyCodeServlet.java
package com.xmyself.servlet; import java.io.IOException; import javax.imageio.ImageIO;import javax.servlet.ServletConfig;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; import com.xmyself.factory.VerifyCodeFactory;import com.xmyself.model.VerifyCode; public class VerifyCodeServlet extends HttpServlet {   private static final long serialVersionUID = 1L;    public void init(ServletConfig config) throws ServletException {   }    public void doPost(HttpServletRequest request, HttpServletResponse response)           throws IOException, ServletException {   }    public void doGet(HttpServletRequest request, HttpServletResponse response)           throws IOException, ServletException {       VerifyCode vc = VerifyCodeFactory.create();       request.getsession().setAttribute("verifyCode", vc.getCode());       ImageIO.write(vc.getImage(), "JPEG", response.getOutputStream());   }    public void destroy() {   }}配置web.xml
<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"    version="2.5">    <display-name>servlet</display-name>          <servlet>        <servlet-name>test</servlet-name>        <servlet-class>com.xmyself.servlet.VerifyCodeServlet</servlet-class>    </servlet>    <servlet-mapping>        <servlet-name>test</servlet-name>        <url-pattern>/test</url-pattern>    </servlet-mapping></web-app>啟動web工程，訪問以下鏈接即可看到驗證碼圖片
http://localhost:8080/servlet/test