[ROCKETMQ-81] import rocketmq plugin for spark streaming

[hustfxj]

This plugin is for spark streaming based on pull mode. And you can see READ.ME for more details. And we will add more tests for this plugin after that.

[vongosling]

@dongeforever @shroman @stevenschew thoughts?

[ranqiqiang]

感谢 。 这个东西 能正式使用了吗？ 期待

[shroman]

@vongosling There are two PRs for ROCKETMQ-81. I guess @hustfxj or @vesense will have to compile them in one, and they recheck it together :)

Guys, please make sure you assign JIRA issues to yourselves before you start working on tasks, and update them. For instance, @hustfxj if you are working on the issue, please change the status, so @vesense knows you are working on it and doesn't waste his time. Two pull requests are submitted but the issue has still "Open" status :D

In fact, I think it's pretty common to pick the issue and work on it if there is no progress on it for a long time.

[zhouxinyu]

Agree with @shroman .
But this two PRs are different implementations, based on PUSH and PULL models respectively, may be both can coexist.

[shroman]

@zhouxinyu yes, luckily they are :)
IMO, if the difference is just PUSH and PULL models, it's reasonable to merge them and improve. Any other ideas?

[vesense]

I plan to merge these two PRs into one. @hustfxj What do you think about it?

[hustfxj]

@vesense It's great! thank you

[zhouxinyu]

@vesense How much the merge progress has been made now?

[vesense]

@zhouxinyu Almost complete. I will submit it in this week. Some delay due to my computer wasn't working in the past few days. 😄

[zhouxinyu]

@vesense Thanks for your efforts~ 😄

[vesense]

I have completed the merging. The PR after merged is here: #4. Now I think we can merge it initially.
The following is the change:

• merge PR [ROCKETMQ-81] import rocketmq plugin for spark streaming #5 to [ROCKETMQ-81] Add the RocketMq plugin for the Apache Spark #4
• fix the jdk version to 1.8
• fix package path
• merge common configs to java/org.apache.rocketmq.spark.RocketMQConfig
• merge common utils to scala/org.apache.rocketmq.spark.RocketMqUtils
• add RocketMQServerMock to improve testing
• improve document

Thanks.