Jfinal验证码功能

//验证码工具类

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;

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;
            }
        }
}

//Controller类（调用该方法来产生一个新的验证码）

public class CaptchaController extends Controller {
    /**
    * @Title: index
    * @Description: TODO(产生一个验证码)
    * void
    */
    public void index(){
        render(new MyCaptchaRender(60,22,4,true));
    }

//路由配置

public class FrontRoutes extends Routes
{
    public void config()
    {
            add("/captcha",CaptchaController.class);
    }

//页面代码

<body>

<img src="${path!}/captcha/index" id="checkCode" style="cursor: pointer;height: 70%;width: 80%;"  title="点击刷新验证码" />

</body>

<script type="text/javascript">

//点击更换验证码
$(function(){
    $("#checkCode").click(function(){
        $(this).attr("src","${path!}/captcha?d="+Math.random().toString());
    });
});
</script>

//效果图