Jfinal框架登陆页面的图形验证码

本文转自，http://www.bubuko.com/infodetail-720511.html

验证码的工具类， 这个jfinal自带的也有，但是下面这个和Jfinal自带的有一点点小的改动，（我用Jfinal自带的，在action中判断输入的验证码和系统随机生成的做对比的时候，出了问题。自带的类好像要用到MD5加密手动输入的验证码后才能判断，（这个我也不太清楚，只是我的感觉 -，- ！，真希望能有位好心人为我这样的菜鸟解答一下。））。呜，这个类也是在网上找的文章产考改的。。

package com.springscapital.console.ext.render;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.security.MessageDigest;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.Cookie;

import com.jfinal.core.Controller;
import com.jfinal.kit.StringKit;
import com.jfinal.render.Render;
 /**
  *
  * @author Administrator
  *    图形验证类
  */
public class MyCaptchaRender extends Render
{
    private static final long serialVersionUID = -7599510915228560611L;
    private static final String[] strArr = {"3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "J", "K", "M", "N", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y"};
    private static String randomCodeKey = "JFINAL_JLHHWH_Key";
    private static boolean caseInsensitive = true;
    private int img_width = 85;
    private int img_height = 20;
    private int img_randNumber = 6;
    public MyCaptchaRender() {
    }
    public MyCaptchaRender(String randomKey) {
        if (StringKit.isBlank(randomKey))
            throw new IllegalArgumentException("randomKey can not be blank");
        randomCodeKey = randomKey;
    }
    public MyCaptchaRender(int width, int height, int count, boolean isCaseInsensitive) {
        if(width <=0 || height <=0 || count <=0)
        {
            throw new IllegalArgumentException("Image width or height or count must be > 0");
        }
        this.img_width = width;
        this.img_height = height;
        this.img_randNumber = count;
        caseInsensitive = isCaseInsensitive;
    }
    public MyCaptchaRender(String randomKey,int width, int height, int count, boolean isCaseInsensitive) {
        if (StringKit.isBlank(randomKey))
            throw new IllegalArgumentException("randomKey can not be blank");
        randomCodeKey = randomKey;
        if(width <=0 || height <=0 || count <=0)
        {
            throw new IllegalArgumentException("Image width or height or count must be > 0");
        }
        this.img_width = width;
        this.img_height = height;
        this.img_randNumber = count;
        caseInsensitive = isCaseInsensitive;
    }
    public void render() {
        BufferedImage image = new BufferedImage(img_width, img_height, BufferedImage.TYPE_INT_RGB);
        String vCode = drawGraphic(image);
        vCode = encrypt(vCode);
        Cookie cookie = new Cookie(randomCodeKey, vCode);
        cookie.setMaxAge(-1);
        cookie.setPath("/");
        response.addCookie(cookie);
        response.setHeader("Pragma","no-cache");
        response.setHeader("Cache-Control","no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");
        ServletOutputStream sos = null;
        try {
            sos = response.getOutputStream();
            ImageIO.write(image, "jpeg",sos);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        finally {
            if (sos != null)
                try {sos.close();} catch (IOException e) {e.printStackTrace();}
        }
    }
    private String drawGraphic(BufferedImage image){
        // 获取图形上下文
        Graphics g = image.createGraphics();
        // 生成随机类
        Random random = new Random();
        // 设定背景色
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, img_width, img_height);
        // 设定字体
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(img_width);
            int y = random.nextInt(img_height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }
        // 取随机产生的认证码(img_randNumber位数字)
        String sRand = "";
        for (int i = 0; i < img_randNumber; i++) {
            String rand = String.valueOf(strArr[random.nextInt(strArr.length)]);
            sRand += rand;
            // 将认证码显示到图象中
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
            g.drawString(rand, 13 * i + 6, 16);
        }
        // 图象生效
        g.dispose();
        return sRand;
    }

    /*
     * 给定范围获得随机颜色
     */
    private Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255)
            fc = 255;
        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }

    private static final String encrypt(String srcStr) {
        try {
            String result = "";
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] bytes = md.digest(srcStr.getBytes("utf-8"));
            for(byte b:bytes){
                String hex = Integer.toHexString(b&0xFF).toUpperCase();
                result += ((hex.length() ==1 ) ? "0" : "") + hex;
            }
            return result;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static boolean validate(Controller controller, String inputRandomCode) {
        if (StringKit.isBlank(inputRandomCode))
            return false;
        try {
            if(caseInsensitive)
                inputRandomCode = inputRandomCode.toUpperCase();
            inputRandomCode = encrypt(inputRandomCode);
            return inputRandomCode.equals(controller.getCookie(randomCodeKey));
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

}

　

　　　Action 中的代码 ：

package com.springscapital.console.site.controller;

import com.jfinal.core.Controller;
import com.springscapital.console.ext.render.MyCaptchaRender;

public class HomeController extends Controller{
    public void index() {
        render("/site/login.html");
    }
    //验证输入的和系统生成的验证码是否一样
    public void login() {
        String inputRandomCode = getPara("captcha");
        boolean validate = MyCaptchaRender.validate(this, inputRandomCode);
        System.out.println("CaptchaRender.validate=" + validate + ";inputRandomCode=" + inputRandomCode);
    }
    //生成图片
    public void captcha(){
        render(new MyCaptchaRender(60,22,4,true));
    }

}

接下来就是页面中的代码了， 这个我也好纠结，本来想加个看不清换一张的按钮然后用ajax异步刷新验证码的，可惜没实现，页面中被我注释掉的代码就是我用的ajax，但是没搞出来，又有点小郁闷了，希望哪位大神看到了能为小弟解惑。

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<!-- <script type="text/javascript" src="${ctx!}/static/js/jquery-1.8.3.js"></script>
<script type="text/javascript">
    $(function() {
        $(".sumbit").click(
            function() {
                $.ajax( {
                    url : "${ctx!}/site/captcha",//发送请求的地址
                    data : {
                        account : $("#captcha").val()//发送到服务器的数据
                    },
                    error : function() {
                        alert("error: 网络异常请稍后再尝试!!!");//请求失败时弹出的信息
                    }
                     success : function(data) {//返回的信息展示出来
                        $(".hint").html(data);//请求成功时，调用的函数
                    }
                });
            });
    });
</script> -->
</head>
<body>
        <div class="main" align="center">
             <form action="${ctx!}/site/login" method="post">
                <table>
                    <tr>
                        <td>用户名：</td>
                        <td><input type="text" name="username"/></td>
                    </tr>
                    <tr>
                        <td>密   码：</td>
                        <td><input type="password" name="pwd"/></td>
                    </tr>
                    <tr>
                        <td><img src="${ctx!}/site/captcha">&nbsp;</td>
                        <td>
                            <input type="text"id="captcha" name="captcha" value=""/>
                       <!-- <input class="sumbit" type="button" value="看不清换一张">
                            <input type=button value=刷新 onclick="location.reload()">  -->
                        </td>
                    </tr>
                    <tr>
                        <td>&nbsp;</td>
                        <td>
                        <INPUT TYPE="reset" name = "reset" value = "重 置">
                        &nbsp;&nbsp;&nbsp;
                        <input type="submit" value="登陆"/>
                        </td>
                    </tr>
                </table>
            </form>
        </div>
</body>
</html>