cookie实现访问时间查看

package day01.cookies;
import java.io.IOException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * 记录用户上次访问的时间
 *
 * @author mzy
 *
 */
public class LastTimeServlet extends HttpServlet {
	private static final long serialVersionUID = 613621422104403409L;
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("utf-8");
		response.setContentType("text/html;charset=utf-8");
		Cookie[] cookies = request.getCookies();
		String lastTime = null;
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日hh时mm分ss秒");
		String nowTime = sdf.format(new Date());
		if(cookies != null) {
			for(Cookie cookie : cookies) {
				if("lastTime".equals(cookie.getName())) {
					response.getWriter().write("欢迎您再次访问本站，当前时间为："+nowTime+"<br/>");
					lastTime = cookie.getValue();
					response.getWriter().write("您上次访问的时间为："+URLDecoder.decode(lastTime, "utf-8"));
					// Cookie c = new Cookie("lastTime", URLEncoder.encode(nowTime, "utf-8"));
					// response.addCookie(c);
					cookie.setValue(URLEncoder.encode(nowTime, "utf-8"));
					response.addCookie(cookie);
					break;
				}
			}
		}
		// cookie虽然不为空，但是并没有我们需要的lastTime数据
		if(cookies == null || lastTime == null ) {
			response.getWriter().write("欢迎您首次访问本站，当前的时间为："+nowTime);
			// 并不需要lastTime数据，因为我们得到lastTime实际是从cookie中获取的
			// lastTime = nowTime;
			Cookie c =  new Cookie("lastTime", URLEncoder.encode(lastTime, "utf-8"));
			response.addCookie(c);
		}
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("text/html");
	}
}