错误信息如下：

Exception in thread "main" org.apache.rocketmq.remoting.exception.RemotingTooMuchRequestException: sendDefaultImpl call timeout
	at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.sendDefaultImpl(DefaultMQProducerImpl.java:640)
	at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.send(DefaultMQProducerImpl.java:1310)
	at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.send(DefaultMQProducerImpl.java:1256)
	at org.apache.rocketmq.client.producer.DefaultMQProducer.send(DefaultMQProducer.java:339)
	at com.dream21th.rocketmq.producer.ProducerSync.main(ProducerSync.java:29)

debug调试代码，发现rocketmq联的ip地址是172.31.152.219

由于是使用的阿里云部署的rocketmq，我们登录服务器，发现内网的ip和上面的一致。所以通过外网是访问不了的。

通过下面指令编写一个broker.properties文件，并制定ip

[root@iZm5e8xpme70yxqoa4zoydZ conf]# pwd
/home/app/rocketmq/conf
[root@iZm5e8xpme70yxqoa4zoydZ conf]# echo brokerIP1=118.190.62.94 >> broker.properties

    重新启动broker，再次运行代码正常

[root@iZm5e8xpme70yxqoa4zoydZ conf]# mqbroker -n 118.190.62.94:9876 -c broker.properties &