验证码自动更新

每分钟对登录界面的验证码进行自动刷新。
js代码：

//输入验证码文本框：
<div style="text-align: center;" class="verificationCode-panel">
		<input  id="codeText" class="form-focus"  placeholder=" 请输入验证码"/>
		<img  class="verificationCode" src="/verificationCode/getVerificationCode?_="+(new Date()).getTime() />
</div>

//绑定点击事件：点击进行刷新
$('.verificationCode').click(function () {
        $(this).attr('src','/verificationCode/getVerificationCode?_='+(new Date()).getTime());
    });
 
//每分钟自动更新相当于每分钟点击一次   
function timeFunction(){
		$('.verificationCode').click();
	}
	
//页面加载时会进行刷新
window.onload =function () {
        $('.verificationCode').click();

		setInterval(timeFunction, 60000);//每分钟自动更新一次验证码

    }

java代码：

//生成验证码：
	@RequestMapping("/verificationCode/getVerificationCode")
	public void getVerificationCode(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 设置不缓存图片
		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "No-cache");
		response.setDateHeader("Expires", 0);
		// 指定生成的响应图片,一定不能缺少这句话,否则错误.
		response.setContentType("image/jpeg");
		int width = 86, height = 22; // 指定生成验证码的宽度和高度
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 创建BufferedImage对象,其作用相当于一图片
		Graphics g = image.getGraphics(); // 创建Graphics对象,其作用相当于画笔
		Graphics2D g2d = (Graphics2D) g; // 创建Grapchics2D对象
		Random random = new Random();
		Font mfont = new Font("微软雅黑", Font.CENTER_BASELINE, 17); // 定义字体样式
		g.setColor(getRandColor(200, 250));
		g.fillRect(0, 0, width, height); // 绘制背景
		g.setFont(mfont); // 设置字体
		g.setColor(getRandColor(180, 200));

		// 绘制100条颜色和位置全部为随机产生的线条,该线条为2f
		for (int i = 0; i < 100; i++) {
			int x = random.nextInt(width - 1);
			int y = random.nextInt(height - 1);
			int x1 = random.nextInt(6) + 1;
			int y1 = random.nextInt(12) + 1;
			BasicStroke bs = new BasicStroke(1f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL); // 定制线条样式
			Line2D line = new Line2D.Double(x, y, x + x1, y + y1);
			g2d.setStroke(bs);
			g2d.draw(line); // 绘制直线
		}
		// 输出由英文，数字，和中文随机组成的验证文字，具体的组合方式根据生成随机数确定。
		String sRand = "";
		String ctmp = "";
		int itmp = 0;
		// 制定输出的验证码为四位
		for (int i = 0; i < 4; i++) {
			switch (random.nextInt(3)) {
			case 10: // 生成A-Z的字母
				itmp = random.nextInt(26) + 65;
				ctmp = String.valueOf((char) itmp);
				break;
			default:
				itmp = random.nextInt(10) + 48;
				ctmp = String.valueOf((char) itmp);
				break;
			}
			sRand += ctmp;
			Color color = new Color(20 + random.nextInt(110), 20 + random.nextInt(110), random.nextInt(110));
			g.setColor(color);
			// 将生成的随机数进行随机缩放并旋转制定角度 PS.建议不要对文字进行缩放与旋转,因为这样图片可能不正常显示
			/* 将文字旋转制定角度 */
			Graphics2D g2d_word = (Graphics2D) g;
			AffineTransform trans = new AffineTransform();
			trans.rotate((45) * 3.14 / 180, 15 * i + 8, 7);
			/* 缩放文字 */
			float scaleSize = random.nextFloat() + 0.8f;
			if (scaleSize > 1f)
				scaleSize = 1f;
			trans.scale(scaleSize, scaleSize);
			g2d_word.setTransform(trans);
			g.drawString(ctmp, 15 * i + 12, 14);
		}
		HttpSession session = request.getSession();
		session.removeAttribute("verificationCode");
		session.setAttribute("verificationCode", sRand);
		g.dispose(); // 释放g所占用的系统资源
		ImageIO.write(image, "JPEG", response.getOutputStream()); // 输出图片
	}