scala，import test._ ; import test.{ClassA,ClassB}

在scala中，*不是通配符，下斜杠“_”才是通配符。因此当使用某个package所有的类时，直接使用：import test._；使用某几个时，直接使用：import test.{ClassA,ClassB}

• Do you want to use the whole package? Use import me.test._.
• Do you want to cherry-pick only some parts of the package? Use import me.test.{ ClassOne, classTwo }.

参考：https://softwareengineering.stackexchange.com/questions/194686/why-does-scala-use-the-operator-for-package-import-instead-of-as-in-java