使用JDK自带缓存（Cache）实现Cookie自动登陆

自定义一个缓存类AdminCache

package jw.admin.common;

import jw.base.entity.Admin;
import sun.security.util.Cache;

public class AdminCache {

    //第一个参数表示cache对象中允许添加的键值对数量，第二个参数表示缓存的时间，单位是秒
    private static Cache cache = Cache.newHardMemoryCache(0,3600 * 24 * 7);

    public static Admin get(String key){
        return (Admin)cache.get(key);
    }
    public static void set(String key,Admin admin){
        AdminCache.cache.put(key,admin);
    }

}

登陆成功发送Cookie到客户端并保存到缓存中

//如果选择记住登录状态，把用户签名保存到cookie中，把签名和签名的对象保存到缓存中
if (remember == true){
    Cookie cookie = new Cookie("adminSign",admin.sign());
    cookie.setMaxAge(60 * 60 * 24 * 7);
    cookie.setPath("/");
    response.addCookie(cookie);
    AdminCache.set(admin.sign(),admin);
}

在spring-servlet中配置拦截器路径

<mvc:interceptors>
        <!-- 使用bean定义一个Interceptor，直接定义在mvc:interceptors根下面的Interceptor将拦截所有的请求 -->
        <bean class="jw.admin.interceptor.AuthInterceptor"/>
        <bean class="jw.admin.interceptor.AuthCookieInterceptor"/>
</mvc:interceptors>

拦截器内容

package jw.admin.interceptor;

import jw.admin.common.AdminCache;
import jw.base.entity.Admin;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class AuthCookieInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HttpSession session = request.getSession();

        //判断session中的用户信息是否存在，不存在从cookie中获取然后装如session
        if(session.getAttribute("admin") == null){
            Cookie[] cookies = request.getCookies();
            if(cookies != null && cookies.length > 0){
                for(int i = 0; i < cookies.length; i++){
                    if(cookies[i].getName().equals("adminSign")){
                        String sign = cookies[i].getValue();
                        Admin admin = AdminCache.get(sign); //根据签名获取用户的完整信息装如session
                        session.setAttribute("admin",admin);
                        break;
                    }
                }
            }
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}