Java建立圖形驗證碼工具類

public class RandomValidateCodeUtil {

	public static final String RANDOMCODEKEY = "RANDOMVALIDATECODEKEY";// 放到session中的key
	private String randString = "0123456789";// 随機産生隻有數字的字元串 private String
	// private String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随機産生隻有字母的字元串
	// private String randString =
	// "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随機産生數字與字母組合的字元串
	private int width = 95;// 圖檔寬
	private int height = 25;// 圖檔高
	private int lineSize = 40;// 幹擾線數量
	private int stringNum = 4;// 随機産生字元數量

	private static final Logger logger = LoggerFactory.getLogger(RandomValidateCodeUtil.class);

	private Random random = new Random();

	/**
	 * 獲得字型
	 */
	private Font getFont() {
		return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
	}

	/**
	 * 獲得顔色
	 */
	private Color getRandColor(int fc, int bc) {
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc - 16);
		int g = fc + random.nextInt(bc - fc - 14);
		int b = fc + random.nextInt(bc - fc - 18);
		return new Color(r, g, b);
	}

	/**
	 * 生成随機圖檔
	 */
	public void getRandcode(HttpServletRequest request, HttpServletResponse response) {
		HttpSession session = request.getSession();
		// BufferedImage類是具有緩沖區的Image類,Image類是用于描述圖像資訊的類
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
		Graphics g = image.getGraphics();// 産生Image對象的Graphics對象,改對象可以在圖像上進行各種繪制操作
		g.fillRect(0, 0, width, height);// 圖檔大小
		g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));// 字型大小
		g.setColor(getRandColor(110, 133));// 字型顔色
		// 繪制幹擾線
		for (int i = 0; i <= lineSize; i++) {
			drowLine(g);
		}
		// 繪制随機字元
		String randomString = "";
		for (int i = 1; i <= stringNum; i++) {
			randomString = drowString(g, randomString, i);
		}
		logger.info(randomString);
		// 将生成的随機字元串儲存到session中
		session.removeAttribute(RANDOMCODEKEY);
		session.setAttribute(RANDOMCODEKEY, randomString);
		g.dispose();
		try {
			// 将記憶體中的圖檔通過流動形式輸出到用戶端
			ImageIO.write(image, "JPEG", response.getOutputStream());
		} catch (Exception e) {
			logger.error("将記憶體中的圖檔通過流動形式輸出到用戶端失敗>>>>   ", e);
		}

	}

	/**
	 * 繪制字元串
	 */
	private String drowString(Graphics g, String randomString, int i) {
		g.setFont(getFont());
		g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));
		String rand = String.valueOf(getRandomString(random.nextInt(randString.length())));
		randomString += rand;
		g.translate(random.nextInt(3), random.nextInt(3));
		g.drawString(rand, 13 * i, 16);
		return randomString;
	}

	/**
	 * 繪制幹擾線
	 */
	private void drowLine(Graphics g) {
		int x = random.nextInt(width);
		int y = random.nextInt(height);
		int xl = random.nextInt(13);
		int yl = random.nextInt(15);
		g.drawLine(x, y, x + xl, y + yl);
	}

	/**
	 * 擷取随機的字元
	 */
	public String getRandomString(int num) {
		return String.valueOf(randString.charAt(num));
	}

	public static Boolean checkVerify(String verifiCode, HttpSession httpSession) {
		if (StringUtils.isEmpty(verifiCode)) {
			return false;
		}
		String random = (String) httpSession.getAttribute("RANDOMVALIDATECODEKEY");
		if (StringUtils.isEmpty(random)) {
			return false;
		}
		if (!random.equals(verifiCode)) {
			return false;
		}
		return true;
	}
}