验证码相关工具类

VerifyCodeUtil 对验证码进行处理

package com.imooc.myo2o.util;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * 对验证码进行处理
 * @author Zhm
 * @date 2020/3/27 16:05
 **/
public class VerifyCodeUtil {
    public static String drawRandomText(int width, int height, BufferedImage verifyImg) {
        Graphics2D graphics = (Graphics2D) verifyImg.getGraphics();
        graphics.setColor(Color.WHITE);//设置画笔颜色-验证码背景色
        graphics.fillRect(0, 0, width, height);//填充背景
        graphics.setFont(new Font("微软雅黑", Font.BOLD, 40));

        //数字和字母的组合
        String baseNumLetter = "123456789abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";
        StringBuffer sBuffer = new StringBuffer();
        int x = 10;  //旋转原点的 x 坐标
        String ch = "";
        Random random = new Random();

        for (int i = 0; i < 4; i++) {
            graphics.setColor(getRandomColor());

            //设置字体旋转角度
            int degree = random.nextInt() % 30;  //角度小于30度
            int dot = random.nextInt(baseNumLetter.length());
            ch = baseNumLetter.charAt(dot) + "";
            sBuffer.append(ch);

            //正向旋转
            graphics.rotate(degree * Math.PI / 180, x, 45);
            graphics.drawString(ch, x, 45);

            //反向旋转
            graphics.rotate(-degree * Math.PI / 180, x, 45);

            x += 48;
        }

        //画干扰线
        for (int i = 0; i < 6; i++) {

            // 设置随机颜色
            graphics.setColor(getRandomColor());

            // 随机画线
            graphics.drawLine(random.nextInt(width), random.nextInt(height),
                    random.nextInt(width), random.nextInt(height));
        }
        //添加噪点

        for (int i = 0; i < 30; i++) {

            int x1 = random.nextInt(width);

            int y1 = random.nextInt(height);

            graphics.setColor(getRandomColor());

            graphics.fillRect(x1, y1, 2, 2);
        }
        return sBuffer.toString();
    }

    /**
     * 随机取色
     */
    private static Color getRandomColor() {

        Random ran = new Random();

        Color color = new Color(ran.nextInt(256),

                ran.nextInt(256), ran.nextInt(256));

        return color;

    }
}

在Controller层中的类调用生成图片方法时需要编写以下方法：

/**
     * 获取验证码图片
     * @param response
     * @param request
     */
    @RequestMapping(value = "/getVerifyCode", method = RequestMethod.GET)
    public void getVerificationCode(HttpServletResponse response, HttpServletRequest request) {
        try {
        	//设置图片的尺寸
            int width = 200;
            int height = 69;
            BufferedImage verifyImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

            //生成对应宽高的初始图片
            String randomText = VerifyCodeUtil.drawRandomText(width, height, verifyImg);

            //单独的一个类方法，出于代码复用考虑，进行了封装。
            //功能是生成验证码字符并加上噪点，干扰线，返回值为验证码字符
            request.getSession().setAttribute("verifyCode", randomText);
            response.setContentType("image/png");//必须设置响应内容类型为图片，否则前台不识别
            OutputStream os = response.getOutputStream(); //获取文件输出流
            ImageIO.write(verifyImg, "png", os);//输出图片流
            os.flush();
            os.close();//关闭流
        } catch (IOException e) {
            e.printStackTrace();
        }
        
    }

CodeUtil 判断用户输入的验证码是否正确

package com.imooc.myo2o.util;

import javax.servlet.http.HttpServletRequest;

/**
 * 判断用户输入的验证码是否正确
 * @author Zhm
 * @date 2020/3/27 16:46
 **/
public class CodeUtil {
    public static boolean checkVerifyCode(HttpServletRequest request){
        String verifyCodeExpected = (String) request.getSession().getAttribute("verifyCode");
        System.out.println(verifyCodeExpected);
        String verifyCodeActual = HttpServletRequestUtil.getString(request,"verifyCodeActual");
        System.out.println(verifyCodeActual);  //null
        if(verifyCodeActual == null || !verifyCodeActual.equalsIgnoreCase(verifyCodeExpected)){
            return false;
        }
        return true;
    }
}