How to skip empty lines when copying files with Gradle?

问题

I would like to copy some files in Gradle and the resulting files should not contain any blank lines, i.e., the blank lines are not copied. I assume that can be done with filter(...) and maybe with the TokenFilter from ant. However, I am not sure how to the syntax would look like.

Thanks.

回答1:

Gradle uses Ant for filtering, because of its powerful implementation. For example, you can use the LineContainsRegExp Ant filter to filter out any line that is only empty or whitespaces.

The appropriate regexp can be [^ \n\t\r]+

You can use Ant directly from Gradle like this:

task copyTheAntWay {
  ant.copy(file:'input.txt', tofile:'output.txt', overwrite:true) {
    filterchain {
      filterreader(classname:'org.apache.tools.ant.filters.LineContainsRegExp') {
        param(type:'regexp', value:'[^ \n\t\r]+')
      }
    }
  }
}

or by using the Gradle CopySpec's filter method:

task copyGradlefied(type:Copy) {
  def regexp = new org.apache.tools.ant.types.RegularExpression()
  regexp.pattern = '[^ \n\t\r]+'

  from(projectDir) {
    include 'input.txt'
    filter(org.apache.tools.ant.filters.LineContainsRegExp, regexps:[regexp])
  }
  into "outputDir"
}

来源：https://stackoverflow.com/questions/14952955/how-to-skip-empty-lines-when-copying-files-with-gradle