Cache<String, String> tokenMap = CacheBuilder.newBuilder()
            //设置并发级别为8，并发级别是指可以同时写缓存的线程数
            .concurrencyLevel(8)
            //设置写缓存后8秒钟过期
            .expireAfterWrite(2, TimeUnit.HOURS)
            //设置缓存容器的初始容量为10
            .initialCapacity(100)
            //设置缓存最大容量为100，超过100之后就会按照LRU最近虽少使用算法来移除缓存项
            .maximumSize(1000)
            //设置缓存的移除通知
            .removalListener(new RemovalListener<Object, Object>() {
                @Override
                public void onRemoval(RemovalNotification<Object, Object> notification) {
                    System.out.println(notification.getKey() + " was removed, cause is " + notification.getCause());
                }
            })
            .build();