Java后端生成验证码图片base64加密发送给前端

验证码生成的工具类VerifyCodeUtils

/**
 * @author kite
 * @date 21/3/24 21:47
 */
@Component
public class VerifyCodeUtils{


    //使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符
    public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
    private static Random random = new Random();


    /**
     * 使用系统默认字符源生成验证码
     *
     * @param verifySize 验证码长度
     * @return
     */
    public static String generateVerifyCode(int verifySize) {
        return generateVerifyCode(verifySize, VERIFY_CODES);
    }

    /**
     * 使用指定源生成验证码
     *
     * @param verifySize 验证码长度
     * @param sources    验证码字符源
     * @return
     */
    public static String generateVerifyCode(int verifySize, String sources) {
        if (sources == null || sources.length() == 0) {
            sources = VERIFY_CODES;
        }
        int codesLen = sources.length();
        Random rand = new Random(System.currentTimeMillis());
        StringBuilder verifyCode = new StringBuilder(verifySize);
        for (int i = 0; i < verifySize; i++) {
            verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));
        }
        return verifyCode.toString();
    }

    /**
     * 输出指定验证码图片流
     *
     * @param w
     * @param h
     * @param os
     * @param code
     * @throws IOException
     */
    public static void outputImage(int w, int h, OutputStream os, String code) throws IOException {
        int verifySize = code.length();
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Random rand = new Random();
        Graphics2D g2 = image.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        Color[] colors = new Color[5];
        Color[] colorSpaces = new Color[]{Color.WHITE, Color.CYAN,
                Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
                Color.PINK, Color.YELLOW};
        float[] fractions = new float[colors.length];
        for (int i = 0; i < colors.length; i++) {
            colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
            fractions[i] = rand.nextFloat();
        }
        Arrays.sort(fractions);

        g2.setColor(Color.GRAY);// 设置边框色
        g2.fillRect(0, 0, w, h);

        Color c = getRandColor(200, 250);
        g2.setColor(c);// 设置背景色
        g2.fillRect(0, 2, w, h - 4);

//        //绘制干扰线
//        Random random = new Random();
//        g2.setColor(getRandColor(160, 200));// 设置线条的颜色
//        for (int i = 0; i < 20; i++) {
//            int x = random.nextInt(w - 1);
//            int y = random.nextInt(h - 1);
//            int xl = random.nextInt(6) + 1;
//            int yl = random.nextInt(12) + 1;
//            g2.drawLine(x, y, x + xl + 40, y + yl + 20);
//        }
//
//        // 添加噪点
//        float yawpRate = 0.05f;// 噪声率
//        int area = (int) (yawpRate * w * h);
//        for (int i = 0; i < area; i++) {
//            int x = random.nextInt(w);
//            int y = random.nextInt(h);
//            int rgb = getRandomIntColor();
//            image.setRGB(x, y, rgb);
//        }

        shear(g2, w, h, c);// 使图片扭曲

        g2.setColor(getRandColor(100, 160));
        int fontSize = h - 4;
        Font font = new Font("Algerian", Font.ITALIC, fontSize);
        g2.setFont(font);
        char[] chars = code.toCharArray();
        for (int i = 0; i < verifySize; i++) {
            AffineTransform affine = new AffineTransform();
            affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize / 2, h / 2);
            g2.setTransform(affine);
            g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
        }

        g2.dispose();
        ImageIO.write(image, "jpg", os);
    }

    private static Color getRandColor(int fc, int bc) {
        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 static int getRandomIntColor() {
        int[] rgb = getRandomRgb();
        int color = 0;
        for (int c : rgb) {
            color = color << 8;
            color = color | c;
        }
        return color;
    }

    private static int[] getRandomRgb() {
        int[] rgb = new int[3];
        for (int i = 0; i < 3; i++) {
            rgb[i] = random.nextInt(255);
        }
        return rgb;
    }

    private static void shear(Graphics g, int w1, int h1, Color color) {
        shearX(g, w1, h1, color);
        shearY(g, w1, h1, color);
    }

    private static void shearX(Graphics g, int w1, int h1, Color color) {

        int period = random.nextInt(2);

        boolean borderGap = true;
        int frames = 1;
        int phase = random.nextInt(2);

        for (int i = 0; i < h1; i++) {
            double d = (double) (period >> 1)
                    * Math.sin((double) i / (double) period
                    + (6.2831853071795862D * (double) phase)
                    / (double) frames);
            g.copyArea(0, i, w1, 1, (int) d, 0);
            if (borderGap) {
                g.setColor(color);
                g.drawLine((int) d, i, 0, i);
                g.drawLine((int) d + w1, i, w1, i);
            }
        }

    }

    private static void shearY(Graphics g, int w1, int h1, Color color) {

        int period = random.nextInt(40) + 10; // 50;

        boolean borderGap = true;
        int frames = 20;
        int phase = 7;
        for (int i = 0; i < w1; i++) {
            double d = (double) (period >> 1)
                    * Math.sin((double) i / (double) period
                    + (6.2831853071795862D * (double) phase)
                    / (double) frames);
            g.copyArea(i, 0, 1, h1, 0, (int) d);
            if (borderGap) {
                g.setColor(color);
                g.drawLine(i, (int) d, i, 0);
                g.drawLine(i, (int) d + h1, i, h1);
            }

        }

    }

    /**
     * 获取随机验证码及其加密图片
     *
     * @param w
     * @param h
     * @param size
     * @return
     * @throws IOException
     */
    public static ImgResult VerifyCode(int w, int h, int size) throws IOException {
        BASE64Encoder encoder = new BASE64Encoder();
        ImgResult rs = new ImgResult();
        String code = generateVerifyCode(size).toLowerCase();
        rs.setCode(encoder.encode(code.getBytes()));
        ByteArrayOutputStream data = new ByteArrayOutputStream();
        outputImage(w, h, data, code);
        rs.setImg(encoder.encode(data.toByteArray()));
        return rs;
    }

}

验证码的使用

@Autowired
private VerifyCodeUtils verifyCodeUtils;

String result="";
ImgResult res = verifyCodeUtils.VerifyCode(80, 30, 4);
Map<String,String> data = new HashMap<>();
data.put("image",res.getImg());
data.put("code",res.getCode());
result = JSON.toJSONString(data);
return result;

前端接收验证码

<img src="data:image/gif;base64,image">

base64.encode(code);

简单方便美观的验证码图片

1.引入pom依赖

<!--        验证码工具类-->
        <!-- https://mvnrepository.com/artifact/cn.hutool/hutool-captcha -->
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-captcha</artifactId>
            <version>5.6.0</version>
        </dependency>

2.直接使用

    /**
     * 宽
     */
    private final Integer WIDTH = 120;
    /**
     * 高
     */
    private final Integer HEIGHT = 40;
    /**
     * 编码长度
     */
    private final Integer CODE_COUNT = 4;
    /**
     * 干扰线数
     */
    private final Integer LINE_COUNT = 20;
    
    
    @GetMapping("/checkCode")
    public ServiceResponse checkCode() throws IOException{
        BASE64Encoder encoder = new BASE64Encoder();
        LineCaptcha lineCaptcha = CaptchaUtil.createLineCaptcha(WIDTH, HEIGHT, CODE_COUNT, LINE_COUNT);
        Map<String,String> data = new HashMap<>();
        data.put("image",lineCaptcha.getImageBase64());
        data.put("code",encoder.encode(lineCaptcha.getCode().getBytes()));
        return new ServiceResponse().succeed(data);
    }