kafka命令行生产者消费者测试

【README】

基于命令行开启生产者，消费者线程，测试kafka的消费转发功能； 

【1】生产者与消费者

生产者201

[[email protected] logs]# kafka-console-producer.sh --topic first --broker-list centos201:9092
>hello-world
>sichuan-changdu
>

消费者202

[[email protected] logs]# kafka-console-consumer.sh --topic first --zookeeper centos201:2181
Using the ConsoleConsumer with old consumer is deprecated and will be removed in a future major release. Consider using the new consumer by passing [bootstrap-server] instead of [zookeeper].
hello-world
sichuan-changdu

注意： 消费者202在生产者201 发送消息前就已经启动了； 所以能够收到所有生产者数据； 
此后203再启动消费者线程，如下：

[[email protected] logs]#  kafka-console-consumer.sh --topic first --zookeeper centos201:2181
Using the ConsoleConsumer with old consumer is deprecated and will be removed in a future major release. Consider using the new consumer by passing [bootstrap-server] instead of [zookeeper].

执行结果说明：显然201机器开启生产者线程，写入了数据到 kafka， hello-world等； 202机器开启了消费者线程，可以收到201机器写入的数据； 但201写完之后， 203 再开启了消费者线程，203收不到之前201写入的数据；
但当我们在开启消费者线程时，加上参数 --from-beginning 时可以消费或收到201之前写的数据；只不过消息无序了；

[[email protected] logs]#  kafka-console-consumer.sh --topic first --zookeeper centos201:2181 --from-beginning
Using the ConsoleConsumer with old consumer is deprecated and will be removed in a future major release. Consider using the new consumer by passing [bootstrap-server] instead of [zookeeper].
sichuan-changdu
hello-world
sichuan-deyang

补充：因为 提示命令过期，所以使用 bootstrap-server 来启动消费者 

[email protected] logs]# kafka-console-consumer.sh --topic first --bootstrap-server centos201:9092
sichuan-nanchong

-- 从头开始消费
[[email protected] logs]# kafka-console-consumer.sh --topic first --bootstrap-server centos201:9092 --from-beginning
sichuan-deyang
sichuan-nanchong
sichuan-changdu
hello-world
sichuan-mianyang