imagecreator.java

图片验证码

package tool;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;

public class ImageCreator {

	// 字符数组
	private char mapTable[] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i',
			'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
			'w', 'z', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8',
			'9' };

	/**
	 * 得到图片对象的字符串 和图片对象
	 * 
	 * @param width
	 *            宽度
	 * @param height
	 *            高度
	 * @param out
	 *            输出流对象 字节流的所有类的超类 子类对象即可
	 * @return 字符串
	 */
	public String getImage(int width, int height, OutputStream os) {
	
		if (width <= 0) {
			width = 80; // 默认宽度
		}
		if (height <= 0) {
			height = 30; // 默认高度
		}

		// java.awt.image.BufferedImage; 图像数据缓冲区
		BufferedImage image = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_RGB);

		// 获取图形上下文
		Graphics graphics = image.getGraphics();

		// 设定背景色
		graphics.setColor(new Color(0xFFCCDC));
		graphics.fillRect(0, 0, width, height);

		// 画边框
		graphics.setColor(Color.black);
		graphics.drawRect(0, 0, width-1 , height-1);

		// 取随机产生的认证码
		String strImageString = "";

		// 5代码5为验证码
		for (int i = 0; i < 5; i++) {
			strImageString += mapTable[(int) (mapTable.length * Math.random())];
		}
		// 将认证码显示到图像中
		graphics.setColor(Color.black);
		graphics.setFont(new Font("Arial", Font.PLAIN, 18));
		String string = strImageString.substring(0, 1);
		graphics.drawString(string, 8, 27);

		string = strImageString.substring(1, 2);
		graphics.drawString(string, 20, 15);

		string = strImageString.substring(2, 3);
		graphics.drawString(string, 35, 18);

		string = strImageString.substring(3, 4);
		graphics.drawString(string, 47, 20);

		string = strImageString.substring(4, 5);
		graphics.drawString(string, 58, 22);

		// 随机产生100干扰点
		for (int i = 0; i < 100; i++) {
			int x = new Random().nextInt(width);
			int y = new Random().nextInt(height);
			graphics.drawOval(x, y, 1, 1);
		}

		// 释放图形上下文
		graphics.dispose();

		try {
			ImageIO.write(image, "JPEG", os);
			
		} catch (Exception e) {
			return "";
		}
		
		return strImageString;
	}
}