struts2生成随机验证码图片

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！");
        }
    }
}
<%@ 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="<%=basePath%>">
    
    <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="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="createImageAction.action" onclick="this.src='createImageAction.action?'+ Math.random()" title="点击图片刷新验证码"/><br>
        <s:actionerror cssStyle="color:red"/>
        
        <s:submit value="提交"></s:submit>
    
    </s:form>

  </body>
</html>