자바 의 랜 덤 인증 코드 생 성 클래스

package cn.edu.hbcit.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;
//         
public class RandomNumUtil {
	private ByteArrayInputStream image;//  ユ  �
	private String str;//        �

	private RandomNumUtil() {
		init();//        х   
	}

	/*
	 *      andomNumUtil    �
	 */
	public static RandomNumUtil Instance() {
		return new RandomNumUtil();
	}

	/*
	 *               �
	 */
	public ByteArrayInputStream getImage() {
		return this.image;
	}

	/*
	 *        у ㄥ       ()
	 */
	public String getString() {
		return this.str;
	}

	private void init() {
		//  ︺   �            
		int width = 63, height = 20;
		BufferedImage image = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_RGB);
		//        ц   ﹣    �
		Graphics g = image.getGraphics();
		//  ㈢         
		Random random = new Random();
		//             
		g.setColor(getRandColor(200, 250));
		g.fillRect(0, 0, width, height);
		//      �   
		g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
		//     �   �55  �                                              �
		g.setColor(getRandColor(160, 200));
		for (int i = 0; i < 155; i++) {
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int xl = random.nextInt(12);
			int yl = random.nextInt(12);
			g.drawLine(x, y, x + xl, y + yl);
		}
		//     ㈤     ㈢         6 ｅ   � �
		String sRand = "";
		for (int i = 0; i < 4; i++) {
			String rand = String.valueOf(random.nextInt(10));
			sRand += rand;
			//                     � �
			g.setColor(new Color(20 + random.nextInt(110), 20 + random
					.nextInt(110), 20 + random.nextInt(110)));
			//     ら  ユ                                �              ч           �
			g.drawString(rand, 13 * i + 6, 16);
		}
		//  у       
		this.str = sRand;

		//  ユ       
		g.dispose();
		ByteArrayInputStream input = null;
		ByteArrayOutputStream output = new ByteArrayOutputStream();
		try {
			ImageOutputStream imageOut = ImageIO
					.createImageOutputStream(output);
			ImageIO.write(image, "JPEG", imageOut);
			imageOut.close();
			input = new ByteArrayInputStream(output.toByteArray());
		} catch (Exception e) {
			System.out.println("                         ょ " + e.toString());
		}

		this.image = input;/*  у    у  */
	}

	/*
	 *        ㄦ              �
	 */
	private Color getRandColor(int fc, int bc) {
		Random random = new Random();
		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);
	}
}