登陆界面验证码实现

login.jsp

<form method="post" action="user_login.action">
				<label class="control-label" for="inputUser"> <span
					class="icon-user"></span>
				</label>
					<input  type="text" id="inputUser"  name="sysuserinfo.userCode" placeholder="学号"
						required="required" pattern="[0-9]{10}" value="">
				<label class="control-label" for="inputPassword"> <span
					class="icon-password"></span>
				</label>

					<input type="password" id="inputPassword" name="sysuserinfo.password"
						required="required" placeholder="密码">
				<label class="control-label" for="inputCode"> <span
					class="icon-key"></span>
					<input type="text"  name="chknumber" required="required" placeholder="验证码" maxlength="5" > 
						<img id="imgCode"
						title="看不清楚请点击这里" src="<%=basePath%>randomCode.action" onclick="reloadcode(this,'<%=basePath%>')" alt="验证码"
						/>
</form>

RandomAction.java

public class RandomCodeAction extends ActionSupport implements SessionAware,
		ServletResponseAware {

	private Map<String, Object> session;
	private HttpServletResponse response;
	private static final long serialVersionUID = 1L;

	/**
	 * 生成验证码
	 */
	@Override
	public String execute() throws Exception {
		log.error("LOGIN-INFO:RandomCodeAction-execute()");
		response.setHeader("Cache-Control", "no-cache");
		int width = 60; // 图片宽度
		int height = 20; // 图片高度
		BufferedImage image = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_RGB);
		Graphics graphics = image.createGraphics();
		graphics.setColor(this.getColor()); // 背景颜色
		graphics.fillRect(0, 0, width, height);
		graphics.setFont(new Font("Arial", Font.BOLD, 18));
		graphics.setColor(this.getColor()); // 字的颜色
		String number = String
				.valueOf(System.currentTimeMillis() % 9000 + 1000);
		// 生成四位随机数
		System.out.println("系统验证码：" + number);
		if (number == null) {
			System.out.println("hahah");
		}
		session.put("randomCode", number); // 写入session中
		graphics.drawString(number, (int) (width * 0.1), (int) (height * 0.8));
		graphics.dispose();
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(response
				.getOutputStream());
		encoder.encode(image);
		response.getOutputStream().flush(); // 刷新到页面生成图片
		response.getOutputStream().close(); // 关闭writer
		return null;
	}

	private Color getColor() {
		int red = (int) (Math.random() * 1000 % 256);
		int green = (int) (Math.random() * 1000 % 256);
		int blue = (int) (Math.random() * 1000 % 256);
		return new Color(red, green, blue);
	}

	public void setSession(Map<String, Object> session) {
		this.session = session;
	}

	public void setServletResponse(HttpServletResponse response) {
		this.response = response;
	}

}

struts.xml

<package name="comAction" namespace="/" extends="struts-default">
		
		<action name="randomCodeAction" class="cn.edu.nwsuaf.comAction.RandomCodeAction">
		</action>
</package>

效果：