删除已过期的Apple Worldwide Developer Relations Certification Authority证书
http://www.jianshu.com/p/9dc2aad90539

Launchpad ->其他 -> 钥匙串访问
http://www.jianshu.com/p/af1e98321574

先建一个普通的maven项目, 然后在项目上右键,configure, Add Scala Nature.

参考http://stackoverflow.com/questions/12533885/could-not-calculate-build-plan-plugin-org-apache-maven-pluginsmaven-resources
Could not calculate build plan: Plugin org.apache.maven.plugins:maven-resources-plugin:2.5 or one of its dependencies could not be resolved

I had the exact same problem and since I read somewhere that the error was caused by a cached file, I fixed it by deleting all the files under de .m2 repository folder. The next time I built the project I had to download all the dependencies again but it was worth it - 0 errors!!

经测试, 在多个程序同时向同一个kafka topic中写入数据, 不会出现数据冲突或者丢失的情况.

测试数据:

向kafka中写数据

program instance 1 : 10000条数据
program instance 2 : 10000条数据
program instance 3 : 10000条数据

同时启动上述3个程序, 程序每次写完一条数据,sleep 50ms.

从kafka中读取数据

共读取到30000条数据

结论

在多个程序同时向同一个kafka topic中写入数据, 不会出现数据冲突或者丢失的情况.

只会有一个consumer能够读取到数据, 其它的consumer是无法消费到数据的. 谁要是知道怎么做,恳请告知!

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filelist=`ls /home/work/file/`
for file in $filelist
do 
 echo $file
done

一定要切记filelist=后边的那个引号不是单引号，而是tab键上边的那个键，或者说是1左边的那个键。否则的话不起作用。

转自http://blog.163.com/clevertanglei900@126/blog/static/111352259201162553652150

http://es.xiaoleilu.com/052_Mapping_Analysis/35_Inverted_index.html

使用以下方式查看elasticsearch中type的mapping

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GET /my_index/_mapping/my_type

详情请参考https://www.elastic.co/guide/en/elasticsearch/guide/current/mapping-intro.html#_viewing_the_mapping