如何在scala.js中使用scala.sys.process

发布时间：2020-12-16 10:06:02 所属栏目：安全来源：网络整理

导读：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

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

解决方法

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……)

（编辑：李大同）

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