拾光分享网 | 一个有趣的IT资源分享网

Jfinal学习心得之验证码的几种实现方法

第一种方法:

在xxxControl 控制器下面新建返回验证码的方法:

    public void captcha() {
    renderCaptcha();
}

在前台页面中这样调用:

<img title="点击刷新" class="captcha" src="/login/captcha" onclick="updateCaptcha();">

<script>
function updateCaptcha() {
   $(".captcha").attr("src", "/login/captcha?v=" + Math.random());
    $("#captchaInput").val("");
}
</script>

后台验证验证码是否正确:

boolean result = validateCaptcha("inputRandomCode");//inputRandomCode是用户提交过来的验证码

第二种方法,自己新建一个类来实现:

    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.StrKit;
import com.jfinal.render.Render;


/**
* @Author www.hiai.top
* @Email  goodsking@163.com
* 图形验证类
*/

public class MyCaptchaRender extends Render{
    @SuppressWarnings("unused")
    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 (StrKit.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 (StrKit.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, 23);
        }
        // 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 (StrKit.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;
        }
    }
 
}

后台这样验证验证码是否正确:

boolean validate = MyCaptchaRender.validate(this, inputRandomCode);//inputRandomCode是用户提交过来的验证码

前台的调用同上面的使用方法

第二种方法控制验证的大小,以及验证中间的字体显示的位置,在代码的第115行中,显示的是坐标:

// 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, 23);
欢迎您的转载:拾光分享网 | 一个有趣的IT资源分享网 » Jfinal学习心得之验证码的几种实现方法


评论 抢沙发

  • 昵称*
  • 邮箱 (必填)
  • 网址