package com.xiaoluo.action;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionSupport;public class CreateImageAction extends ActionSupport{    private ByteArrayInputStream inputStream;    private static int WIDTH = 60;    private static int HEIGHT = 20;    public ByteArrayInputStream getInputStream()    {        return inputStream;    }    public void setInputStream(ByteArrayInputStream inputStream)    {        this.inputStream = inputStream;    }
    private static String createRandom()    {        String str = "0123456789qwertyuiopasdfghjklzxcvbnm";        char[] rands = new char[4];        Random random = new Random();        for (int i = 0; i < 4; i++)        {            rands[i] = str.charAt(random.nextInt(36));        }        return new String(rands);    }    private void drawBackground(Graphics g)    {        // 画背景        g.setColor(new Color(0xDCDCDC));        g.fillRect(0, 0, WIDTH, HEIGHT);        // 随机产生 120 个干扰点        for (int i = 0; i < 120; i++)        {            int x = (int) (Math.random() * WIDTH);            int y = (int) (Math.random() * HEIGHT);            int red = (int) (Math.random() * 255);            int green = (int) (Math.random() * 255);            int blue = (int) (Math.random() * 255);            g.setColor(new Color(red, green, blue));            g.drawOval(x, y, 1, 0);        }    }    private void drawRands(Graphics g, String rands)    {        g.setColor(Color.BLACK);        g.setFont(new Font(null, Font.ITALIC | Font.BOLD, 18));        // 在不同的高度上输出验证码的每个字符        g.drawString("" + rands.charAt(0), 1, 17);        g.drawString("" + rands.charAt(1), 16, 15);        g.drawString("" + rands.charAt(2), 31, 18);        g.drawString("" + rands.charAt(3), 46, 16);        System.out.println(rands);    }    @Override    public String execute() throws Exception    {        HttpServletResponse response = ServletActionContext.getResponse();        // 设置浏览器不要缓存此图片        response.setHeader("Pragma", "no-cache");        response.setHeader("Cache-Control", "no-cache");        response.setDateHeader("Expires", 0);        String rands = createRandom();        BufferedImage image = new BufferedImage(WIDTH, HEIGHT,                BufferedImage.TYPE_INT_RGB);        Graphics g = image.getGraphics();        // 产生图像        drawBackground(g);        drawRands(g, rands);        // 结束图像 的绘制 过程， 完成图像        g.dispose();        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();        ImageIO.write(image, "jpeg", outputStream);        ByteArrayInputStream input = new ByteArrayInputStream(outputStream                .toByteArray());        this.setInputStream(input);        HttpSession session = ServletActionContext.getRequest().getSession();        session.setAttribute("checkCode", rands);                input.close();                outputStream.close();        return SUCCESS;    }}

package com.xiaoluo.action;import javax.servlet.http.HttpSession;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class LoginValidateAction extends ActionSupport{    private String checkCode;        public String getCheckCode()    {        return checkCode;    }    public void setCheckCode(String checkCode)    {        this.checkCode = checkCode;    }    @Override    public String execute() throws Exception    {        return SUCCESS;    }        @Override    public void validate()    {        HttpSession session = ServletActionContext.getRequest().getSession();                String checkCode2 = (String)session.getAttribute("checkCode");                if(!checkCode.equals(checkCode2))        {            this.addActionError("输入的验证码不正确，请重新输入！");        }    }}

　　　　　　<action name="createImageAction" class="com.xiaoluo.action.CreateImageAction">                <result name="success" type="stream">                    <param name="contentType">image/jpeg</param>                    <param name="inputName">inputStream</param>                </result>　　　　　　  </action>                        <action name="loginValidateAction" class="com.xiaoluo.action.LoginValidateAction">                <result name="success">/success.jsp</result>                <result name="input">/login.jsp</result>            </action>

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><html>  <head>    <base href="http://www.mamicode.com/">        <title>My JSP ‘login.jsp‘ starting page</title>        <meta http-equiv="pragma" content="no-cache">    <meta http-equiv="cache-control" content="no-cache">    <meta http-equiv="expires" content="0">        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">    <meta http-equiv="description" content="This is my page">    <!--    <link rel="stylesheet" type="text/css" href="http://www.mamicode.com/styles.css">    -->      </head>    <body>    <h3><font color="blue">带有验证码的登陆界面</font></h3>        <s:form action="loginValidateAction.action" theme="simple">            用户名:<s:textfield name="username"></s:textfield><br>        密码    :<s:password name="password"></s:password><br>        验证码:<s:textfield name="checkCode"></s:textfield>
　　　　　
　　　　　<!--若要点击图片刷新，重新得到一个验证码，要在后面加上个随机数，这样保证每次提交过去的都是不一样的path，防止因为缓存而使图片不刷新-->        <img src="http://www.mamicode.com/createImageAction.action" onclick="this.src=http://www.mamicode.com/‘createImageAction.action?‘+ Math.random()" title="点击图片刷新验证码"/><br>        <s:actionerror cssStyle="color:red"/>                <s:submit value="http://www.mamicode.com/提交"></s:submit>        </s:form>  </body></html>