Shiro 限制并发人数登录与剔除

一、创建一个实现 AccessControlFilter 的过滤器类

package com.beovo.dsd.common.shiro.filter;

import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.util.ObjectUtil;
import com.beovo.dsd.common.shiro.ShiroFilterUtils;
import com.beovo.dsd.common.shiro.ShiroUser;
import org.apache.shiro.cache.Cache;
import org.apache.shiro.cache.CacheManager;
import org.apache.shiro.session.Session;
import org.apache.shiro.session.mgt.DefaultSessionKey;
import org.apache.shiro.session.mgt.SessionManager;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.web.filter.AccessControlFilter;
import org.apache.shiro.web.util.WebUtils;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.Serializable;
import java.util.Deque;
import java.util.LinkedList;

/**
 * 限制并发人数登录与剔除
 * @author Jimc.
 * @since 2018/11/28.
 */
public class KickoutSessionControlFilter extends AccessControlFilter {

    private static final String KICKOUT_CACHE_NAME = "kickoutCache";
    private static final String KICKOUT = "kickout";

    /**
     * 踢出后到的地址
     */
    private String kickoutUrl;
    /**
     * 踢出之前登录的/之后登录的用户,默认踢出之前登录的用户
     */
    private boolean kickoutAfter = false;
    /**
     * 同一个帐号最大会话数,默认1
     */
    private int maxSession = 1;

    private SessionManager sessionManager;
    private Cache<String, Deque<Serializable>> cache;

    public void setKickoutUrl(String kickoutUrl) {
        this.kickoutUrl = kickoutUrl;
    }

    public void setKickoutAfter(boolean kickoutAfter) {
        this.kickoutAfter = kickoutAfter;
    }

    public void setMaxSession(int maxSession) {
        this.maxSession = maxSession;
    }

    public void setSessionManager(SessionManager sessionManager) {
        this.sessionManager = sessionManager;
    }

    public void setCacheManager(CacheManager cacheManager) {
        this.cache = cacheManager.getCache(KICKOUT_CACHE_NAME);
    }

    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) throws Exception {
        return false;
    }

    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        Subject subject = getSubject(request, response);
        if(!subject.isAuthenticated() && !subject.isRemembered()) {
            //如果没有登录，直接进行之后的流程
            return true;
        }

        Session session = subject.getSession();
        ShiroUser user = (ShiroUser)subject.getPrincipal();
        String username = user.getAccount();
        Serializable sessionId = session.getId();

        // 同步控制
        Deque<Serializable> deque = cache.get(username);
        if(CollUtil.isEmpty(deque)) {
            deque = new LinkedList<Serializable>();
            cache.put(username, deque);
        }

        //如果队列里没有此sessionId，且用户没有被踢出；放入队列
        if(!deque.contains(sessionId) && ObjectUtil.isNull(session.getAttribute(KICKOUT))) {
            deque.push(sessionId);
        }

        //如果队列里的sessionId数超出最大会话数，开始踢人
        while(deque.size() > maxSession) {
            Serializable kickoutSessionId = null;
            if(kickoutAfter) { //如果踢出后者
                kickoutSessionId = deque.removeFirst();
            } else { //否则踢出前者
                kickoutSessionId = deque.removeLast();
            }
            try {
                Session kickoutSession = sessionManager.getSession(new DefaultSessionKey(kickoutSessionId));
                if(ObjectUtil.isNotNull(kickoutSession)) {
                    // 设置会话的kickout属性表示踢出了
                    kickoutSession.setAttribute(KICKOUT, true);
                }
            } catch (Exception e) {//ignore exception
            }
        }

        // 如果被踢出了，直接退出，重定向到踢出后的地址
        if (ObjectUtil.isNotNull(session.getAttribute(KICKOUT))) {
            // 会话被踢出了
            try {
                subject.logout();
            } catch (Exception e) { //ignore
            }
            saveRequest(request);

            HttpServletRequest httpRequest = WebUtils.toHttp(request);
            if (ShiroFilterUtils.isAjax(httpRequest)) {
                HttpServletResponse res = WebUtils.toHttp(response);
                // 采用res.sendError(401);在Easyui中会处理掉error，$.ajaxSetup中监听不到
                res.setHeader("oauthstatus", "401");
                return false;
            } else {
                WebUtils.issueRedirect(request, response, kickoutUrl);
                return false;
            }
        }

        return true;
    }
}

二、将过滤器加入到shiro的配置中

<!-- 并发登处理 -->
    <bean id="kickoutSessionControlFilter" class="com.beovo.dsd.common.shiro.filter.KickoutSessionControlFilter">
        <property name="cacheManager" ref="shiroSpringCacheManager"/>
        <property name="sessionManager" ref="sessionManager"/>
        <!-- 是否踢出后来登录的，默认是false；即后者登录的用户踢出前者登录的用户 -->
        <property name="kickoutAfter" value="false"/>
        <!-- 同一个用户最大的会话数，默认1；比如2的意思是同一个用户允许最多同时两个人登录 -->
        <property name="maxSession" value="1"/>
        <!-- 踢出后到的地址 -->
        <property name="kickoutUrl" value="/login"/>
    </bean>

<!-- Shiro Filter -->
    <bean id="shiroFilter" class="org.apache.shiro.spring.web.ShiroFilterFactoryBean">
        <!-- 安全管理器 -->
        <property name="securityManager" ref="securityManager"/>
        <!-- 默认的登陆访问url -->
        <property name="loginUrl" value="/login"/>
        <!-- 登陆成功后跳转的url -->
        <property name="successUrl" value="/index"/>
        <!-- 没有权限跳转的url -->
        <property name="unauthorizedUrl" value="/unauth"/>
        <property name="filterChainDefinitions">
            <value>
                <!--
                    anon  不需要认证
                    authc 需要认证
                    user  验证通过或RememberMe登录的都可以
                    kickout 需要验证并发登录
                -->
                /login = anon
                /captcha = anon
                /resources/** = anon
                /** = user,kickout
            </value>
        </property>
        <property name="filters">
            <map>
                <entry key="kickout" value-ref="kickoutSessionControlFilter"/>
            </map>
        </property>
    </bean>

注意：过滤器拦截所有请求那里需要加入 kickout：

/** = user,kickout