net.noday.core.utils.Captcha.java Source code

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Here is the source code for net.noday.core.utils.Captcha.java

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/*
 * Copyright 2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.noday.core.utils;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.imageio.stream.ImageInputStream;

import org.apache.shiro.session.Session;

import org.apache.commons.lang.RandomStringUtils;
import org.apache.commons.lang3.StringUtils;

/**
 * cat Captcha
 *
 * @author <a href="http://www.noday.net">Noday</a>
 * @version , 2012-11-24
 * @since 
 */
public class Captcha {

    private static final Random random = new Random();
    public static final String CAPTCHAKEY = "_key_of_captch";

    public static boolean validate(Session s, String captcha) {
        String text = (String) s.getAttribute(CAPTCHAKEY);
        return StringUtils.equalsIgnoreCase(text, captcha);
    }

    public static ByteArrayInputStream captchInputStream(Session s, int width, int height) throws IOException {
        String text = randText();
        s.setAttribute(CAPTCHAKEY, text);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        ImageIO.write(gen(text, width, height), "png", out);
        return new ByteArrayInputStream(out.toByteArray());
    }

    public static ImageInputStream captcha(Session s, int width, int height) throws IOException {
        String text = randText();
        s.setAttribute(CAPTCHAKEY, text);
        BufferedImage bi = gen(text, width, height);
        return ImageIO.createImageInputStream(bi);
    }

    public static BufferedImage gen(String text, int width, int height) throws IOException {
        BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        Graphics2D g = (Graphics2D) bi.getGraphics();
        g.setColor(Color.GRAY);
        g.fillRect(0, 0, width, height);
        for (int i = 0; i < 10; i++) {
            g.setColor(randColor(150, 250));
            g.drawOval(random.nextInt(110), random.nextInt(24), 5 + random.nextInt(10), 5 + random.nextInt(10));
            Font f = new Font("Arial", Font.ITALIC, 20);
            g.setFont(f);
            g.setColor(randColor(10, 240));
            g.drawString(text, 4, 24);
        }
        return bi;
    }

    private static Color randColor(int fc, int bc) {
        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 String randText() {
        String text = RandomStringUtils.randomAlphanumeric(4).toUpperCase().replace('0', 'A').replace('O', 'E')
                .replace('1', 'V').replace('I', 'R');
        return text;
    }

}