站点经常使用的记住我，或是一周内自己主动登录，这些功能一般都是是用cookie进行登录的！以下对此功能进行分析：

package cookielogin;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class CookieLogin implements Filter {

	private static final String USERNAME = "username";

	private static final String PASSWORD = "password";

	@Override

	public void destroy() {

		// TODO Auto-generated method stub

	}

	@Override

	public void doFilter(ServletRequest request, ServletResponse response,

			FilterChain chain) throws IOException, ServletException {

		HttpServletRequest req = (HttpServletRequest) request;

		HttpServletResponse resp = (HttpServletResponse) response;

		Cookie username = this.getCookie(req, USERNAME);

		Cookie password = this.getCookie(req, PASSWORD);

		if (null != username && null != password) {

			System.out.println("用户登录");

			// userService.login(username.getValue,password.getValue());

			System.out.println("username:" + username.getValue() + ",password:"

					+ password.getValue());

		} else {

			//保存cookie

			resp.setCharacterEncoding("UTF-8");

			Cookie nameCookie = new Cookie(USERNAME, "username");

			Cookie passCookie = new Cookie(PASSWORD, "password");

			resp.addCookie(nameCookie);

			resp.addCookie(passCookie);

		}

		chain.doFilter(req, resp);

	}

	public Cookie getCookie(HttpServletRequest request, String cookieName) {

		Cookie[] cookies = request.getCookies();

		if (null == cookies) {

			return null;

		}

		for (Cookie c : cookies) {

			if (c.getName().equals(cookieName)) {

				return c;

			}

		}

		return null;

	}

	@Override

	public void init(FilterConfig arg0) throws ServletException {

	}

}

測试时须要在web.xm增加拦截器！