验证码实现

怼烎@ 2024-03-16 20:07 49阅读 0赞

## 具体实现 ##

import lombok.extern.slf4j.Slf4j;  
import java.util.Base64;  
import javax.imageio.ImageIO;  
import java.awt.\*;  
import java.awt.image.BufferedImage;  
import java.io.ByteArrayOutputStream;  
import java.io.IOException;  
import java.util.Random;  
import java.util.concurrent.ThreadLocalRandom;

/**
     * 验证码工具类
     *
     */
    @Slf4j
    public class LoginVerification {
    
        public static final String ATU_NAME = "validateRand";
        private static final  ThreadLocal<String> SRAND_THREAD_LOCAL = new ThreadLocal(){
            @Override
            protected Object initialValue() {
                return "";
            }
        };
        private static final ThreadLocalRandom THREAD_LOCAL_RANDOM = ThreadLocalRandom.current();
    
        public static void unloadThreadLocal(){
            SRAND_THREAD_LOCAL.remove();
        }
    
    
        //设置随机的背景颜色
        static Color getRandColor(int fc,int bc) {
            Random random = THREAD_LOCAL_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);
        }
        //具体获取base64串方法
        public static String getPicBase64(){
            BufferedImage pic = LoginVerification.getPic();
            //io流
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            //写入流中
            try {
                ImageIO.write(pic, "JPEG", baos);
            } catch (IOException e) {
                log.error("出现异常:{}",e);
            }
            //转换成字节
            byte[] bytes = baos.toByteArray();
            Base64.Encoder encoder = Base64.getEncoder();
            //转换成base64串
            String png_base64 = encoder.encodeToString(bytes).trim();
            log.info("生成的base64串 替换前:{}",png_base64);
            //删除 \r\n
            png_base64 = png_base64.replaceAll("\n", "").replaceAll("\r", "");
            log.info("生成的base64串 替换后:{}",png_base64);
            return png_base64;
        }
    
        public static BufferedImage getPic() {
            int width=200, height=40;
            BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics g= image.getGraphics();
            Random random = THREAD_LOCAL_RANDOM;
            //设置验证码的文本
            String sRand="";
    
            //设置字体的大小
            Font mFont = new Font("Times New Roman", Font.PLAIN,28);
    
            g.setColor(getRandColor(200,250));
            g.fillRect(0, 0, width, height);
            g.setColor(new Color(102,102,102));
            g.drawRect(0, 0, width-1, height-1);
            g.setFont(mFont);
    
            //设置颜色
            g.setColor(getRandColor(160,200));
            for (int i=0;i<155;i++)
            {
                int x = random.nextInt(width - 1);
                int y = random.nextInt(height - 1);
                int xl = random.nextInt(6) + 1;
                int yl = random.nextInt(12) + 1;
                g.drawLine(x,y,x + xl,y + yl);
            }
            for (int i = 0;i < 70;i++)
            {
                int x = random.nextInt(width - 1);
                int y = random.nextInt(height - 1);
                int xl = random.nextInt(12) + 1;
                int yl = random.nextInt(6) + 1;
                g.drawLine(x,y,x - xl,y - yl);
            }
            //设置验证码的类型
            sRand = three(g);
            log.info("验证码:{}",sRand);
            SRAND_THREAD_LOCAL.set(sRand);
            g.dispose();
    
            return image;
        }
    
    
        /**
         * 获取验证码
         * @return
         */
        public static String getRand(){
            return SRAND_THREAD_LOCAL.get();
        }
        public static String getRandAndClear(){
            String rand = SRAND_THREAD_LOCAL.get();
            unloadThreadLocal();
            return rand;
        }
    
        /**
         * 英文字符加数字的验证码
         */
    
        private static String one(Graphics g){
            Random random = THREAD_LOCAL_RANDOM;
            String sRand = "";
            String[] letter = { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J",
                    "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V",
                    "W", "X", "Y", "Z" };
            for (int i = 0; i < 4; i++) {
                String tempRand = "";
                if (random.nextBoolean()) {
                    tempRand = String.valueOf(random.nextInt(10));
                } else {
                    tempRand = letter[random.nextInt(25)];
                    /* if (random.nextBoolean()) {// 随机将该字母变成小写
                         tempRand = tempRand.toLowerCase();
                     }  */
                }
                sRand += tempRand;
                g.setColor(new Color(20 + random.nextInt(10), 20 + random
                        .nextInt(110), 20 + random.nextInt(110)));
                g.drawString(tempRand,20 * i + 20, 30);
            }
            return sRand;
        }
    
        //英文
        private static String two(Graphics g){
            Random random = THREAD_LOCAL_RANDOM;
            String sRand = "";
            for (int i=0;i<5;i++)
            {
                int itmp = random.nextInt(26) + 65;
                char ctmp = (char)itmp;
                sRand += String.valueOf(ctmp);
                g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
                g.drawString(String.valueOf(ctmp),20*i+10,30);
            }
            return sRand;
        }
        //4个数
        private static String three(Graphics g){
    
            Random random = THREAD_LOCAL_RANDOM;
            String sRand = "";
            for (int i = 0; i < 4; i++) {
                String rand = String.valueOf(random.nextInt(10));
                sRand += rand;
                // 将认证码显示到图象中
                g.setColor(new Color(20 + random.nextInt(110), 20 + random
                        .nextInt(110), 20 + random.nextInt(110)));
                // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
                g.drawString(rand,20*i+10,30);
            }
            return sRand;
        }
        //中文 肆+？=24
        private static String four(Graphics g) {
            Random random = THREAD_LOCAL_RANDOM;
    
            String[] cn = {"壹", "贰", "叁", "肆", "伍", "陆", "柒", "捌", "玖", "拾"};
            int x = random.nextInt(10) + 1;
            int y = random.nextInt(30);
            String sRand = String.valueOf(y);
            g.setFont(new Font("楷体", Font.PLAIN, 25));// 设定字体
            g.setColor(new Color(20 + random.nextInt(10), 20 + random.nextInt(110),
                    20 + random.nextInt(110)));
            g.drawString(cn[x - 1], 1 * 1 + 6, 30);
            g.drawString("+", 33, 30);
            g.drawString("？", 50, 30);
            g.drawString("=", 62, 30);
            g.drawString(String.valueOf(x + y), 75, 30);
            return sRand;
        }
    }