Java随机图片验证码

 

package com.ak.util;

import javax.imageio.ImageIO;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Random;

/**
 * 验证码工具类
 *
 * @author Akeung
 * 2019/12/11 0011
 */
public class ImageVerifyCodeUtil {
    private static final Random random = new Random();
    private static final String[] fontNames = {"宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312", "Georgia"};


    public static String drawImage(ByteArrayOutputStream output) {
        String code;
        int width = 60;
        int height = 30;

        //创建图片缓冲区
        BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
        Graphics2D g = bi.createGraphics();

        //设置背景颜色
        g.setBackground(new Color(255, 255, 255));
        g.clearRect(0, 0, width, height);

        StringBuilder stringBuilder = new StringBuilder();
        //这里只画入四个字符
        for (int i = 0; i < 4; i++) {
            String s = randomChar() + "";      //随机生成字符，因为只有画字符串的方法，没有画字符的方法，所以需要将字符变成字符串再画
            stringBuilder.append(s);           //添加到StringBuilder里面
            float x = i * 1.0F * width / 4;   //定义字符的x坐标
            g.setFont(randomFont());           //设置字体，随机
            g.setColor(randomColor());         //设置颜色，随机
            g.drawString(s, x, height-8);
        }
        code = stringBuilder.toString();//获取验证码字符串

        //定义干扰线的数量（5条）
        Graphics2D graphics = (Graphics2D) bi.getGraphics();
        for (int i = 0; i < 5; i++) {
            int x1 = random.nextInt(width);
            int y1 = random.nextInt(height);
            int x2 = random.nextInt(width);
            int y2 = random.nextInt(height);
            graphics.setColor(randomColor());
            graphics.drawLine(x1, y1, x2, y2);
        }
        // 释放图形上下文
        g.dispose();
        try {
            ImageIO.write(bi, "png", output);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return code;
    }

    //随机字体
    private static Font randomFont() {
        int index = random.nextInt(fontNames.length);
        String fontName = fontNames[index];
        int style = random.nextInt(4);         //随机获取4种字体的样式
        int size = random.nextInt(20) % 6 + 15;    //随机获取字体的大小(15-20之间的值)
        return new Font(fontName, style, size);
    }

    //随机颜色
    private static Color randomColor() {
        int r = random.nextInt(225);
        int g = random.nextInt(225);
        int b = random.nextInt(225);
        return new Color(r, g, b);
    }

    //随机字符
    private static char randomChar() {
        //A-Z,a-z,0-9,可剔除一些难辨认的字母与数字
        String str = "0123456789ABCdefghiDEFGHIJopPQRVWXYZabcjklSTUmnqrstKLMNOvuwxyz";
        return str.charAt(random.nextInt(str.length()));
    }

    public static void main(String[] args) throws IOException {
        File file = new File("D://code.png");
        FileOutputStream fileOutputStream = new FileOutputStream(file);
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        String s = drawImage(byteArrayOutputStream);
        System.out.println(s);
        byteArrayOutputStream.writeTo(fileOutputStream);
        byteArrayOutputStream.flush();
        byteArrayOutputStream.close();
    }
}