未登录

登录实现

将Session Id和用户信息存储到Redis中，并添加一个Cookie。

@WebServlet("/login")
public class Login extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req,resp);
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

            HttpSession session = req.getSession();
            String sessionId = session.getId();

            //设置cookie的名称
            Cookie cookie = new Cookie("sso-cookies",sessionId);
            //子域名可以共享一级域名的cookie
            cookie.setDomain("localhost");
            //设置cookie的访问仅通过http方式，在一定程度上防止脚本攻击
            cookie.setHttpOnly(true);
            //如果不设置该值，则cookie不会保存到硬盘中，只存在于内存中，只在当前页面有效。
            //单位为s,如果设置为-1，则代表永久
            cookie.setMaxAge(60*30);
            //子级目录可以共享根目录下的cookie
            cookie.setPath("/");
            resp.addCookie(cookie);

            //序列化用户信息
            JSONObject user = new JSONObject();
            user.put("name","张三");
            user.put("pwd",123);

            //将sessionId与用户信息保存到Redis中
            Jedis jedis = new Jedis();
            jedis.setex(sessionId,60*30,user.toJSONString());
            
            req.getRequestDispatcher("loginSuccess.jsp").forward(req, resp);
    }
}

登录成功后两个tomcat均有一个相同的cookie

查看redis中session过期时间

查看redis中存储的用户信息

登录情况下获取用户信息

@WebServlet("/getUser")
public class getUser extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取cookies
        Cookie[] cookies = req.getCookies();
        Map<String,Cookie> cookieMap = new HashMap<String,Cookie>();
        if (cookies != null){
            for (Cookie cookie: cookies) {
                cookieMap.put(cookie.getName(),cookie);
            }
        }
        
        Cookie cookie = cookieMap.get("sso-cookies");
       if(StringUtils.isNotBlank(cookie )){
	        String  value= cookie.getValue();
	        Jedis jedis = new Jedis();
	        if (StringUtils.isNotBlank(value) && StringUtils.isNotBlank(jedis.get(value))){
	            JSONObject jsonObject = JSONObject.parseObject(jedis.get(value));
	            jsonObject.put("Tomcat1","Tomcat1");
	            resp.getWriter().println(jsonObject.toString());
        }
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }
}

此时不论从哪个服务器中都能取出用户信息

重置Session过期时间

由于会话session是有过期时间,在一定时间内若不进行任何操作,session便过期,此时再将进行操作将要求重新登录.所有需要对session过期时间进行重置处理

@WebServlet("/rest.do")
public class ResetSession extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        resp.getWriter().println("重置session过期时间!");
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }
}

自定义过滤器处理相应业务

public class SessionExtendFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //将ServletRequest转换为HttpServletRequest
        HttpServletRequest request = (HttpServletRequest)servletRequest;
        Cookie[] cookies = request.getCookies();
        Map<String,Cookie> cookieMap = new HashMap<String,Cookie>();
        if (cookies != null){
            for (Cookie cookie: cookies) {
                cookieMap.put(cookie.getName(),cookie);
            }
        }
        String value=null;
        if (cookieMap.containsKey("sso-cookies")){
            Cookie cookie = cookieMap.get("sso-cookies");
            value= cookie.getValue();
        }
        //如果token不为空的话，符合条件，则获取user信息，user不为空，则将redis缓存中的session时间重置为指定时时长
        if(StringUtils.isNotBlank(value)){
            String userstr = RedisUtil.get(value);
            Object user = JSONObject.parse(userstr);
            if( user!= null){
                //如果user不为空，则重置session的时间，即调用expire命令
                RedisUtil.expire(value, 60*30);
            }
        }
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {

    }
}

web.xml配置过滤器

<web-app>
  <filter>
    <filter-name>sessionExtendFilter</filter-name>
    <filter-class>cn.ybzy.demo.SessionExtendFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>sessionExtendFilter</filter-name>
    <url-pattern>*.do</url-pattern>
  </filter-mapping>
</web-app>

执行过滤器方法及验证

退出销毁session

@WebServlet("/loginout")
public class LoginOut extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        Cookie[] cookies = req.getCookies();
        Map<String,Cookie> cookieMap = new HashMap<String,Cookie>();
        if (cookies != null){
            for (Cookie cookie: cookies) {
                cookieMap.put(cookie.getName(),cookie);
            }
        }

        Cookie cookie = cookieMap.get("sso-cookies");

       if(StringUtils.isNotBlank(cookie )){
        //删除redis中存储session
        Jedis jedis = new Jedis();
        jedis.del(cookie.getValue());

        //删除cookie
        cookie.setDomain("localhost");
        cookie.setPath("/");
        //设置成0，代表删除此cookie
        cookie.setMaxAge(0);
        resp.addCookie(cookie);
        req.getRequestDispatcher("index.jsp").forward(req, resp);
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }
}