imageIO图像流 验证码效果案例

package cn.images;

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

public class CapcahaDemo {
    public static void main(String[] args) throws Exception {
        //验证码的长宽
        int len = 4;
        int width = len * 26;
        int height =50;
        //验证码中的数字 字母
        String letter = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        var rand = new Random();
        StringBuilder sub = new StringBuilder();
        var cc = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
        var g= cc.createGraphics();
        setRenderingHint(g);
        //背景的随机把颜色
        g.setColor(new Color(rand.nextInt(26)+220,rand.nextInt(26)+220,rand.nextInt(26)+220));
        //背景 填充矩形 位置 宽高
        g.fillRect(0,0,width,height);
        //字体颜色
        var c = new Color(rand.nextInt(256),rand.nextInt(256),rand.nextInt(256));
        g.setColor(c);
        //生成四个随机验证码内容
        for(int i = 0;i<len;i++){
            //将其转换成字符串（返回指定索引处的char值。索引范围是从0到length() - 1 （返回一个大于0小于letter的长度的随机数））
            //就是从letter中随机取出一个
            String str  = String.valueOf(letter.charAt(rand.nextInt(letter.length())));
            sub.append(str);
            //验证码中内容的位置
            var x = i*25+5;
            var y = 35;
            //设置文字旋转角度
            double radianPercent = Math.PI*(rand.nextInt(35)/180D);
            if(rand.nextBoolean())
                radianPercent = -radianPercent;
            //文字正向旋转
            g.rotate(radianPercent,x,y);
            //验证码内容的字体样式  粗细正常   字体大小[20-40)
            g.setFont(new Font("微软雅黑",Font.PLAIN,rand.nextInt(20)+20));
            g.drawString(str,x,y);
            //文字反向旋转
            g.rotate(-radianPercent,x,y);

        }
        //干扰文件
        for(int i=0;i<len*10;i++) {
            var x = rand.nextInt(width);
            var y = rand.nextInt(height);
            String str = String.valueOf(letter.charAt(rand.nextInt(letter.length())));
            double radianPercent = Math.PI * (rand.nextInt(35) / 180D);
            //if (rand.nextBoolean())
            //    radianPercent = -radianPercent;
            //g.rotate(radianPercent, x, y);

            c = new Color(rand.nextInt(256), rand.nextInt(256), rand.nextInt(256),rand.nextInt(30)+60);
            g.setColor(c);

            g.setFont(new Font("微软雅黑", Font.PLAIN, rand.nextInt(10) + 10));
            g.drawString(str, x, y);
        }

        // 干扰正统曲线
        //字体颜色相同
        g.setColor(new Color(rand.nextInt(255),rand.nextInt(255),rand.nextInt(255)));

        int yy = rand.nextInt(35)+15;
        int hh = rand.nextInt(20)+10;
        int aa = rand.nextInt(60)+20;

        for(int x= 0; x<width;x++){
            int y = (int)(yy+ hh * Math.sin(x*Math.PI/aa));

            g.fillOval(x,y,5,5);
        }

        g.dispose();

        ImageIO.write(cc,"png",new File("cc.png"));

        Runtime.getRuntime().exec("cmd /k start cc.png");
    }
//设置线条平滑
    public static void setRenderingHint(Graphics2D g) {
        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);
        g.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_DEFAULT);
    }

    public static Font getRandFont(int end, int start) {
        Random rand = new Random();
        Font font = null;
        if(rand.nextBoolean()){
            font = new Font("微软雅黑",Font.PLAIN , rand.nextInt(end) + start);

        }else {
            try{
                Font f = Font.createFont(Font.TRUETYPE_FONT,new File("fonts/zh164hfyh.ttf"));
                font = f.deriveFont(Font.PLAIN,rand.nextInt(end)+ start);
            }catch (Exception e){
                e.printStackTrace();
            }
        }
        return font;
    }

}