如何在scala.js中使用scala.sys.process

Question

我已将scala.sys.process._导入到我的scala.js项目中。 仅此一点不会导致任何问题，但如果我添加一个简单的命令，如println("ls".!!)我会遇到很多错误，比如

[error] Referring to non-existent class java.lang.ProcessBuilder
[error]   called from scala.sys.process.ProcessCreation.apply(scala.collection.Seq,scala.Option,scala.collection.Seq)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.Process$.apply(scala.collection.Seq,scala.Option,scala.collection.Seq)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.ProcessCreation.apply(java.lang.String,scala.Option,scala.collection.Seq)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.Process$.apply(java.lang.String,scala.Option,scala.collection.Seq)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.ProcessCreation.apply(java.lang.String)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.Process$.apply(java.lang.String)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.ProcessImplicits.stringToProcess(java.lang.String)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.package$.stringToProcess(java.lang.String)scala.sys.process.ProcessBuilder
[error]   called from draw.Main$.main(org.scalajs.dom.raw.HTMLCanvasElement)scala.Unit
[error]   called from draw.Main$.$$js$exported$meth$main(org.scalajs.dom.raw.HTMLCanvasElement)java.lang.Object
[error]   called from draw.Main$.main
[error]   exported to JavaScript with @JSExport
[error] involving instantiated classes:
[error]   scala.sys.process.Process$
[error]   scala.sys.process.package$
[error]   draw.Main$
[error] Referring to non-existent class java.io.File
[error]   called from scala.sys.process.ProcessCreation.apply(scala.collection.Seq,scala.Option,scala.collection.Seq)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.Process$.apply(scala.collection.Seq,scala.Option,scala.collection.Seq)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.ProcessCreation.apply(java.lang.String,scala.Option,scala.collection.Seq)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.Process$.apply(java.lang.String,scala.Option,scala.collection.Seq)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.ProcessCreation.apply(java.lang.String)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.Process$.apply(java.lang.String)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.ProcessImplicits.stringToProcess(java.lang.String)scala.sys.process.ProcessBuilder
[error]   called from scala.sys.process.package$.stringToProcess(java.lang.String)scala.sys.process.ProcessBuilder
[error]   called from draw.Main$.main(org.scalajs.dom.raw.HTMLCanvasElement)scala.Unit
[error]   called from draw.Main$.$$js$exported$meth$main(org.scalajs.dom.raw.HTMLCanvasElement)java.lang.Object
[error]   called from draw.Main$.main
[error]   exported to JavaScript with @JSExport
[error] involving instantiated classes:
[error]   scala.sys.process.Process$
[error]   scala.sys.process.package$
[error]   draw.Main$
[error] Referring to non-existent method java.lang.ProcessBuilder.environment()java.util.Map

导入额外的类（如java.lang.ProcessBuilder和java.io.File）对这些错误的内容没有影响。 我在这里缺少一些非常简单的东西吗？

谢谢！

Answer 1

您不能简单地将任意Scala库导入Scala.js - 虽然语言相同，但环境却截然不同。 许多标准的Scala库在SJS世界中根本就不存在，而且很多都不能 ，因为它运行的JavaScript环境的局限性。它在语法上是合法的，所以它会编译，但它不能运行之前没有Scala.js版本的库。

总的来说，您应该假设SJS世界中不存在这样的库，除非您发现有人专门移植了它。 （老实说，我不知道是否有人为Node.js移植了scala.sys.process ;它在浏览器环境中没有多大意义......）