验证码生成

Posted 2020-12-01 notmore

记录一个可用的获取验证码的方式

package top.xzhand.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import top.xzhand.constant.ConstantConfig;
import top.xzhand.service.TokenService;

import javax.annotation.Resource;
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.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

/**
 * 验证码
 */
@RestController
public class CheckCodeController extends HttpServlet {
    // 设置图形验证码中字符串的字体和大小  
    private Font myFont = new Font("Arial Black", Font.PLAIN, 16);

//    @Resource
//    private TokenService tokenService;

    // 生成随机颜色  
    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);
    }

    @RequestMapping("/checkcode")
    public void checkCode(HttpServletRequest request, HttpServletResponse response, String key) throws ServletException, IOException {

        // 阻止生成的页面内容被缓存，保证每次重新生成随机验证码
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");
        // 指定图形验证码图片的大小
        int width = 80, height = 30;
        // 生成一张新图片
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 在图片中绘制内容
        Graphics g = image.getGraphics();
        Random random = new Random();
        g.setColor(getRandColor(200, 250));
        g.fillRect(1, 1, width - 1, height - 1);
        g.setColor(new Color(102, 102, 102));
        g.drawRect(0, 0, width - 1, height - 1);
        g.setFont(myFont);
        // 随机生成线条，让图片看起来更加杂乱
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width - 1);// 起点的x坐标
            int y = random.nextInt(height - 1);// 起点的y坐标
            int x1 = random.nextInt(6) + 1;// x轴偏移量
            int y1 = random.nextInt(12) + 1;// y轴偏移量
            g.drawLine(x, y, x + x1, y + y1);
        }
        // 随机生成线条，让图片看起来更加杂乱
        for (int i = 0; i < 70; i++) {
            int x = random.nextInt(width - 1);
            int y = random.nextInt(height - 1);
            int x1 = random.nextInt(12) + 1;
            int y1 = random.nextInt(6) + 1;
            g.drawLine(x, y, x - x1, y - y1);
        }

//        // 该变量用来保存系统生成的随机字符串
        String sRand = "";
        for (int i = 0; i < 4; i++) {
            // 取得一个随机字符
            String tmp = getRandomChar();
            sRand += tmp;
            // 将系统生成的随机字符添加到图形验证码图片上
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            g.setFont(new Font("TimesRoman", Font.BOLD, 20));
            g.drawString(tmp, 18 * i + 10, 25 - random.nextInt(10));
        }

//        // 取得用户Session
//        HttpSession session = request.getSession(true);
//        // 将系统生成的图形验证码添加
//        session.setAttribute("rand", sRand);

//        RequestUtils.setCookie(request, response, Keys.VERIFY_CODE, sRand,-1);

//        String token = ConstantConfig.CHECKCODE + key;
//        tokenService.setUser(String.valueOf(token), sRand, 60);

        g.dispose();
        // 输出图形验证码图片
        ImageIO.write(image, "JPEG", response.getOutputStream());
    }

    // 随机生成一个字符  
    private String getRandomChar() {
        int rand = 3;// (int) Math.round(Math.random() * 2);// 将0～2的小数四舍五入生成整数
        long itmp = 0;
        char ctmp = ‘u‘;
        // 根据rand的值来决定是生成一个大写字母、小写字母和数字  
        switch (rand) {
            // 生成大写字母的情形
            case 1:
                itmp = Math.round(Math.random() * 25 + 65);
                ctmp = (char) itmp;
                return String.valueOf(ctmp);
            // 生成小写字母  
            case 2:
                itmp = Math.round(Math.random() * 25 + 97);
                ctmp = (char) itmp;
                return String.valueOf(ctmp);
            // 生成数字  
            default:
                itmp = Math.round(Math.random() * 9);
                return String.valueOf(itmp);
        }
    }
}