Java驗證碼圖檔生成源代碼

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

public class Captchautil {

    public static String random() {
        // 使用字元串來接收随機字元
        StringBuffer stringBuffer = new StringBuffer ();
        // 所有的小寫字元
        String arrWord = "abcdefghigklmnopqrstuvwxyz";
        // 使用String.toUpperCase 轉換成大寫字元
        String allCase = arrWord.toUpperCase () + arrWord + "1234567890";
        // 挑選所有的随機字元串轉化為字元數組
        byte[] bytes = allCase.getBytes ();
        // 建立随機抽取
        Random random = new Random ();
        // 擷取4個随機字元并存方法到list集合中
        for (int i = 0; i < 4; i++) {
            int index = random.nextInt (bytes.length + 1);
            // 将對應的ASCII碼值轉換字元存儲
            stringBuffer.append ((char)bytes[index]);

        }
        return stringBuffer.toString ();
    }

    public static void outputImage(String code, OutputStream ops) {
        // 建立Random用來畫幹擾線
        Random random = new Random ();
        // 建立圖檔對象
        BufferedImage image = new BufferedImage (100, 40, BufferedImage.TYPE_3BYTE_BGR);
        // 設定畫布
        Graphics graphics = image.getGraphics ();
        // 設定白色背景
        graphics.setColor (Color.white);
        graphics.fillRect (0, 0, 100, 40);
        byte[] bytes = code.getBytes ();
        // 寫字擷取随機顔色
            graphics.setColor (new Color (random.nextInt (255) + 1,
                    random.nextInt (255) + 1,
                    random.nextInt (255) + 1));
            graphics.setFont (new Font ("微軟雅黑", Font.PLAIN, 20));
            // 設定驗證碼位置
            graphics.drawBytes (bytes, 0, 4, 20, 20);
        // 随機線條
        for (int i = 0; i < 10; i++) {
            graphics.setColor (new Color (random.nextInt (255) + 1,
                    random.nextInt (255) + 1,
                    random.nextInt (255) + 1));
            graphics.drawLine (random.nextInt (100),
                    random.nextInt (40),
                    random.nextInt (100),
                    random.nextInt (40));
        }

        try {
            boolean write = ImageIO.write (image, "png", ops);
            System.out.println (write);
        } catch (IOException e) {
            e.printStackTrace ();
        }


    }

    public static void main(String[] args){
        String code = random ();
        System.out.println (code);
        try {
            // 填寫圖檔的餓導出位置
            OutputStream sot = new FileOutputStream ("I:\\file\\a.png", false);
            outputImage (code, sot);
        } catch (FileNotFoundException e) {
            e.printStackTrace ();
        }


    }
}