java验证码（强烈推荐，只看咱的就够了）

版权声明：转载请指明出处 https://blog.csdn.net/weixin_42321963/article/details/82251714

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Random;

public class Test {
    public static void main(String[] args) {
        Font font = new Font("微软雅黑", Font.BOLD, 25);
        getverfica(100, 100, 10, 50, font);
    }

    public static void getPositon() {

    }

    //
    public static void getverfica(int width, int height, int positionX, int positionY, Font font) {
        BufferedImage img = new BufferedImage(width, height, 1);
        Graphics g = img.getGraphics();
        g.setFont(font);
        int x = positionX;
        int y = positionY;
        //设置颜色，画边框,可以设置成其他色，但太难看，所以设置成白色
        Color color = getColor(true);
        g.setColor(Color.white);
        g.drawRect(0, 0, width, height);
        //设置颜色填充内部，可以设置成其他色，但太难看，所以设置成黑色
        color = getColor(true);
        g.setColor(Color.BLACK);
        g.fillRect(1, 1, width - 2, height - 2);
        //四个不同字体的颜色
        char[] chars = getString(4);
        Random ran = new Random();
        for (int i = 0; i < chars.length; i++) {
            color = getColor(true);
            g.setColor(color);
            g.drawString(chars[i] + "", positionX, positionY);
            positionX = positionX + 15 + ran.nextInt(10);
            positionY = y + ran.nextInt(10);
        }
        //设置干扰字
        chars = getString(50);
        for (int i = 0; i < chars.length; i++) {
            font = new Font("微软雅黑", Font.BOLD, ran.nextInt(15));
            g.setFont(font);
            color = getColor(false);
            g.setColor(color);
            g.drawString(chars[i] + "", positionX, positionY);
            positionX = ran.nextInt(width);
            positionY = ran.nextInt(height);
        }
        //设置干扰线
        int lineCount=140;
        for (int i = 0; i < lineCount; i++) {
            color = getColor(false);
            g.setColor(color);
            g.drawLine(ran.nextInt(width), ran.nextInt(width), ran.nextInt(width), ran.nextInt(width));
        }
        //写入文件
        try {
            ImageIO.write(img, "jpg", new File("d:/test/a.jpg"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //用来取得随机颜色，如果b=true,则透明度为1，否则为随机
    public static Color getColor(boolean b) {
        Random ran = new Random();
        int[] col = new int[3];
        for (int i = 0; i < 3; i++) {
            col[i] = ran.nextInt(255);
        }
        Color color;
        if (b) {
            color = new Color(col[0], col[1], col[2], 254);
        } else {

            //color = new Color(col[0], col[1], col[2], ran.nextInt(255));
            color = new Color(col[0], col[1], col[2], ran.nextInt(120));
            /*String d = String.format("%.2f", Math.random());
            str = "rgba(" + col[0] + "," + col[1] + "," + col[2] + "," + d + ")";*/
        }
        return color;
    }

    //得到随机的n个字符
    public static char[] getString(int n) {
        String str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ123456789";
        char chars[] = new char[n];
        Random ran = new Random();
        for (int i = 0; i < n; i++) {
            chars[i] = str.charAt(ran.nextInt(str.length()));
        }
        for (char a : chars) {
            System.out.println(a);
        }
        return chars;
    }
}

结果如下：