com.eryansky.common.web.servlet.ValidateCodeServlet.java Source code

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Here is the source code for com.eryansky.common.web.servlet.ValidateCodeServlet.java

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/**
 *  Copyright (c) 2012-2014 http://www.eryansky.com
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 */
package com.eryansky.common.web.servlet;

import com.eryansky.common.utils.SysConstants;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.math.NumberUtils;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

/**
 *  ????.
 * 
 * @author &Eryan eryanwcp@gmail.com
 * @date 2013-3-4 ?9:00:06
 */
@SuppressWarnings("serial")
public class ValidateCodeServlet extends HttpServlet {

    private int w = 70;
    private int h = 26;

    public ValidateCodeServlet() {
        super();
    }

    public void destroy() {
        super.destroy();
    }

    /**
     * ?.
     */
    public static boolean validate(HttpServletRequest request, String validateCode) {
        String code = (String) request.getSession().getAttribute(SysConstants.SESSION_VALIDATE_CODE);
        return validateCode.toUpperCase().equalsIgnoreCase(code);
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String validateCode = request.getParameter(SysConstants.SESSION_VALIDATE_CODE); // AJAX??true
        if (StringUtils.isNotBlank(validateCode)) {
            response.getOutputStream().print(validate(request, validateCode) ? "true" : "false");
        } else {
            this.doPost(request, response);
        }
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        createImage(request, response);
    }

    private void createImage(HttpServletRequest request, HttpServletResponse response) throws IOException {

        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");

        /*
         * ??
         */
        String width = request.getParameter("width");
        String height = request.getParameter("height");
        if (StringUtils.isNumeric(width) && StringUtils.isNumeric(height)) {
            w = NumberUtils.toInt(width);
            h = NumberUtils.toInt(height);
        }

        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();

        /*
         * ?
         */
        createBackground(g);

        /*
         * ?
         */
        String s = createCharacter(g);
        request.getSession().setAttribute(SysConstants.SESSION_VALIDATE_CODE, s);

        g.dispose();
        OutputStream out = response.getOutputStream();
        ImageIO.write(image, "JPEG", out);
        out.close();

    }

    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 void createBackground(Graphics g) {
        // 
        g.setColor(getRandColor(220, 250));
        g.fillRect(0, 0, w, h);
        // ?
        for (int i = 0; i < 10; i++) {
            g.setColor(getRandColor(40, 150));
            Random random = new Random();
            int x = random.nextInt(w);
            int y = random.nextInt(h);
            int x1 = random.nextInt(w);
            int y1 = random.nextInt(h);
            g.drawLine(x, y, x1, y1);
        }
    }

    private String createCharacter(Graphics g) {
        char[] codeSeq = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S',
                'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
        String[] fontTypes = { "\u5b8b\u4f53", "\u65b0\u5b8b\u4f53", "\u9ed1\u4f53", "\u6977\u4f53",
                "\u96b6\u4e66" };
        Random random = new Random();
        StringBuilder s = new StringBuilder();
        for (int i = 0; i < 4; i++) {
            String r = String.valueOf(codeSeq[random.nextInt(codeSeq.length)]);//random.nextInt(10));
            g.setColor(new Color(50 + random.nextInt(100), 50 + random.nextInt(100), 50 + random.nextInt(100)));
            g.setFont(new Font(fontTypes[random.nextInt(fontTypes.length)], Font.BOLD, 26));
            g.drawString(r, 15 * i + 5, 19 + random.nextInt(8));
            //         g.drawString(r, i*w/4, h-5);
            s.append(r);
        }
        return s.toString();
    }

}