将验证码代码应用于struts2框架

验证码功能经常应用到网站中，放到此处便于查阅。
核心代码如下，如需全部代码请查看附件。

1、java生成验证码代码如下：（此代码也可放到servlet中）

public class ImageUtil {
	private static String[] chars = { "1", "2", "3", "4", "5", "6", "7", "8", "9" };
	private static final int WIDTH = 200;
	private static final int HEIGHT = 100;
	private static final int NUM = 4;
	private static final int LINE = 10;

	/**
	 * 生成随机图
	 * 
	 * @return string 随机字符 image随机图片
	 */
	public static Map getImage() {
		Map map = new HashMap();
		String s = "";
		// 创建�?个BufferedImage
		BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
				BufferedImage.TYPE_INT_RGB);
		Graphics graphics = image.getGraphics();
		Random ran = new Random();
		// 画背景色
		graphics.setColor(new Color(ran.nextInt(100), ran.nextInt(100), ran
				.nextInt(100)));
		graphics.fillRect(0, 0, WIDTH, HEIGHT);
		// 画随机字�?
		for (int i = 0; i < NUM; i++) {
			graphics.setColor(new Color(ran.nextInt(20)+200, ran.nextInt(20)+200, ran
					.nextInt(200)+20));
			graphics.setFont(new Font(null, Font.BOLD, ran.nextInt(10) + 80));
			String ranstr = chars[ran.nextInt(chars.length)];
			graphics.drawString(ranstr, WIDTH / NUM * (i), HEIGHT / 4 * 3);
			s += ranstr;
		}
		// 画干扰线
		for (int j = 0; j < LINE; j++) {
			graphics.setColor(new Color(ran.nextInt(255), ran.nextInt(255), ran
					.nextInt(255)));
			graphics.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT), ran
					.nextInt(WIDTH), ran.nextInt(HEIGHT));
		}
		map.put("code", s);
		map.put("image", image);
		return map;
	}

	/**
	 * 将随机图片转换成inputStream
	 */
	public static InputStream getInputStream(BufferedImage image)
			throws IOException {
		// 将BufferedImage转换成符合JPEG格式字节数组
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		JPEGImageEncoder encode = JPEGCodec.createJPEGEncoder(bos);
		encode.encode(image);
		// 将图片的字节数组信息，封装成InputStream
		byte[] byteArr = bos.toByteArray();
		return new ByteArrayInputStream(byteArr);
	}

}

2、action引用验证码

public class ImageCodeAction {
	
	private InputStream imageStream;
	
	public String execute() {
		
		Map map = ImageUtil.getImage();
		//存放在session中便于用户输入后进行验证 此处略去
		//getSession().put(Constants.SESSION_CODE, map.get("code"));
		try {
			imageStream = ImageUtil.getInputStream((BufferedImage) map
					.get("image"));
		} catch (IOException e) {
			e.printStackTrace();
		}
		return "success";
	}

	public InputStream getImageStream() {
		return imageStream;
	}

	public void setImageStream(InputStream imageStream) {
		this.imageStream = imageStream;
	}

}