package cn.bingou.filter;import java.io.IOException;
import java.net.URLDecoder;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.HttpSession;import cn.bingou.domain.User;
import cn.bingou.exception.MsgException;
import cn.bingou.factory.BaseFactory;
import cn.bingou.service.UserService;public class AutoLoginFilter implements Filter {private String encode=null;@Overridepublic void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {HttpServletRequest req=(HttpServletRequest) request;// 1.用户没有登陆HttpSession session=req.getSession(false);if(session==null || session.getAttribute("user")==null){Cookie[] cs=req.getCookies();Cookie findC=null;if(cs!=null){for(Cookie c:cs){if("autologin".equals(c.getName())){findC=c;break;}}}// 2.用户携带了自动登录的Cookieif(findC!=null){// 3.自动登陆Cookie中保存的用户名和密码正确String value=findC.getValue(); // username#passwordString username=URLDecoder.decode(value.split("#")[0], encode);String password=value.split("#")[1];UserService service=BaseFactory.getFactory().getInstance(UserService.class);try {User user=service.login(username, password);// 以上3点都符合，再进行自动登陆 -> 将用户的信息存入sessionif(user!=null){// 实现自动登陆 -> session中现在已经有用户的登陆状态// session.setAttribute("user",user); // 空指针req.getSession().setAttribute("user", user);}} catch (MsgException e) {e.printStackTrace();}}}// 放行请求
        chain.doFilter(request, response);}@Overridepublic void init(FilterConfig filterConfig) throws ServletException {this.encode=filterConfig.getServletContext().getInitParameter("encode");}@Overridepublic void destroy() {// TODO Auto-generated method stub
}
}

  <!-- 配置过滤器 --><filter><filter-name>AutoLoginFilter</filter-name><filter-class>cn.bingou.filter.AutoLoginFilter</filter-class></filter><!-- 配置过滤器拦截的url --><filter-mapping><filter-name>AutoLoginFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping>