动态验证码生成类

实现动态验证码的生成 。

package com.gpdi.common.utils;

/**
 * 生成验证码
 */
import com.gpdi.common.contact.SessionConstant;
import sun.misc.BASE64Encoder;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;


public class VerifyUtil {

    /**
     * 随机产生数字与字母组合的字符串
     */
    private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    /**
     * 图片宽
     */
    private int width = 95;
    /**
     * 图片高
     */
    private int height = 25;
    /**
     * 干扰线数量
     */
    private int lineSize = 30;
    /**
     * 随机产生字符数量
     */
    private int stringNum = 4;

    private Random random = new Random();

    /**
     * 获得字体
     */
    private Font getFont() {
        return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
    }

    /**
     * 获得颜色
     */
    private Color getRandColor(int fc, int bc) {
        if (fc > 255) {
            fc = 255;
        }
        if (bc > 255) {
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 18);
        return new Color(r, g, b);
    }

    /**
     * 生成随机图片
     */
    public String getRandcode(HttpServletRequest request, HttpServletResponse response, Boolean toBase64) {
        HttpSession session = request.getSession();
        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);

        // 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
        Graphics g = image.getGraphics();
        //图片大小
        g.fillRect(0, 0, width, height);

        //字体大小
        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
        //字体颜色
//        g.setColor(getRandColor(110, 133));
        g.setColor(new Color(14,99,155));
        // 绘制干扰线
        for (int i = 0; i <= lineSize; i++) {
            drowLine(g);
        }
        // 绘制随机字符
        String randomString = "";
        for (int i = 1; i <= stringNum; i++) {
            randomString = drowString(g, randomString, i);
        }
        //将生成的随机字符串保存到session中
        session.removeAttribute(SessionConstant.VERIFY_CODE_KEY);
        session.setAttribute(SessionConstant.VERIFY_CODE_KEY, randomString);
//        //设置失效时间1分钟
//        session.setMaxInactiveInterval(60);
        g.dispose();

        if(!toBase64){
            try {
                // 将内存中的图片通过流动形式输出到客户端
                ImageIO.write(image, "JPEG", response.getOutputStream());

                return "";
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        return bufferImageToByte(image);
    }


    /**
     * BufferedImage转base64
     * @param image
     * @return
     * @throws IOException
     */
    private String bufferImageToByte(BufferedImage image) {

        //io流
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        //写入流中
        try {
            ImageIO.write(image, "JPEG", baos);
        } catch (IOException e) {
            e.printStackTrace();
        }
        //转换成base64串
        byte[] bytes = baos.toByteArray();
        //转换成字节
        BASE64Encoder encoder = new BASE64Encoder();
        String pngBase64 = encoder.encodeBuffer(bytes).trim();
        pngBase64 = pngBase64.replaceAll("\n", "").replaceAll("\r", "");

        return "data:image/jpeg;base64,"+pngBase64;
    }

    /**
     * 绘制字符串
     */
    private String drowString(Graphics g, String randomString, int i) {
        g.setFont(getFont());
//        g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
//                .nextInt(121)));
        g.setColor(new Color(14, 99, 155));
        String rand = String.valueOf(getRandomString(random.nextInt(randString
                .length())));
        randomString += rand;
        g.translate(random.nextInt(3), random.nextInt(3));
        g.drawString(rand, 13 * i, 16);
        return randomString;
    }

    /**
     * 绘制干扰线
     */
    private void drowLine(Graphics g) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(13);
        int yl = random.nextInt(15);
        g.drawLine(x, y, x + xl, y + yl);
    }

    /**
     * 获取随机的字符
     */
    public String getRandomString(int num) {
        return String.valueOf(randString.charAt(num));
    }

    public static Boolean verifyCode(String codeParam, String sessionVerifyCode){
        return codeParam.toLowerCase().equals(sessionVerifyCode.toLowerCase());
    }

}