big data decode club

记录下常用的Hadoop相关的命令，忘记了容易找 HDFS命令 某个文件的blocks信息 1hadoop fsck /user/xx -files -blocks -locations 释放租约 1hdfs debug recoverLease -path /xxxx.lzo 改变一个文件或者目录的副本因子 1hadoop fs -setrep -R 3 /user/xx 查看app的logyarn logs -applicationId application_1452250357031_0175 set datanode 日志级别hadoop daemonlog -setlevel namenodeip:50070 datanode DEBUG或者 在hadoop-env.sh中添加export HADOOP_ROOT_LOGGER=DEBUG,RFA 查看sequence文件 hadoop dfs -text sequenceFile 查看压缩文件lzo文件(先按照lzop命令) hadoop fs -cat /user/2017-03-06/pa ...

在这里我暂时这样理解，就是把复杂对象的构建过程和结果进行分离 也就是解耦 Builder模式概念The builder pattern is an object creation software design pattern. Unlike the abstract factory pattern and the factory method pattern whose intention is to enable polymorphism, the intention of the builder pattern is to find a solution to the telescoping constructor anti-pattern[citation needed]. The telescoping constructor anti-pattern occurs when the increase of object constructor parameter combination leads to an exponential list of const ...

在这里我暂时这样理解，就是把复杂对象的构建过程和结果进行分离 也就是解耦 Builder模式概念The builder pattern is an object creation software design pattern. Unlike the abstract factory pattern and the factory method pattern whose intention is to enable polymorphism, the intention of the builder pattern is to find a solution to the telescoping constructor anti-pattern[citation needed]. The telescoping constructor anti-pattern occurs when the increase of object constructor parameter combination leads to an exponential list of const ...