正则表达式

最全的常用正则表达式大全——包括校验数字、字符、一些特殊的需求等等

java正则表达式和linux表达式是有一些不一样的

  def test11(): Unit ={
    val date = "2017-08-09"
    val warn = "WARN"
    val strs = Array("2017-08-09 10:24:11,040 RN org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: Checkpoint done. New Image Size: 117430",
      "2017-08-09 11:24:11,570 WARN org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: Checkpoint done. New Image Size: 117230",
      "2017-08-09 11:24:11,570 WA org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: Checkpoint done. New Image Size: 117230",
      "2017-08-09 11:24:11,570 WARN org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: Checkpoint done. New Image Size: 117230")
    strs.filter(_.matches(".*2017-08-09.*WARN.*")).foreach(println(_))
  }

比如,匹配一个日期和单词, scala需要这样写

_.matches(".*2017-08-09.*WARN.*")
shell中需要这样写

cat /home/hadoop/apps/hadoop-2.6.5/logs/hadoop-hadoop-secondarynamenode-mini1.log | grep '2017-08-09.*WARN'

在Java中默认是以要匹配的单词开头的,而linux 不是所以java中需要加上.*