Gradleには設定ファイルがいっぱい ref: http://qiita.com/NewGyu/items/c145136c256f801e1402

build.gradle

apply from: "settings/confA.gradle"

task hoge << {
  println "value:${nanika}"
}

confA.gradle

ext {
  nanika="なにか?"
}

file0.txt

myproject/
├── build.gradle
├── gradle.properties
└── settings.gradle

file10.groovy

ext {
  hoge.fuga="extで設定したよ"
}

file11.groovy

ext {
  set("hoge.fuga","extで設定したよ")
}

file8.txt

$ ./gradlew hoge -Phoge.fuga=commandline

file9.txt

$ ./gradlew hoge -Dhoge.fuga=commandline

gradle.properties

hoge.fuga=hogehogefugafuga
piyo=piyopiyo

ディレクトリ構造

myProject
├── build.gradle
└── settings
    └── confA.gradle