org.mongodb.driver.cluster：连接到服务器127.0.0.1:28017时监视器线程中的异常
com.mongodb.MongoSocketReadException：提前到达流的末尾
WritableServerSelector。集群状态的客户端视图是{type = UNKNOWN，servers = [{address = 127.0.0.1：28017，type = UNKNOWN，state = CONNECTING，exception = {com.mongodb.MongoSocketReadException：提前到达流的末尾}}]