scala.reflect.internal.FatalError: 包 scala 没有成员 Int [英] scala.reflect.internal.FatalError: package scala does not have a member Int

问题描述

我目前正在开发一个使用 Scala 和 Play Framework 2 的项目.我想在运行时编译一些 Scala 代码并从解释器中获取结果.我在网上找了一些例子，最后得出了如下代码:

I am currently working on a project using Scala and Play Framework 2. I want to compile some Scala code during runtime and get the result from the interpreter. I found some examples on the internet and finally came up with the following code:

package controllers

import play.api.mvc.{Action, Controller}
import javax.script.ScriptEngineManager

class Interpreter extends Controller {

    val interpreter = new ScriptEngineManager().getEngineByName("scala")
    val settings = interpreter.asInstanceOf[scala.tools.nsc.interpreter.IMain].settings
    settings.embeddedDefaults[Interpreter]
    settings.usejavacp.value = true

    def index = Action {
        Ok(views.html.interpreter())
    }

    def interpret(input: String) = Action { 
        implicit request => interpreter.eval("1 to 10 foreach println")
        Ok("Got: " + input)
    }
}

object Interpreter

我的问题是，在尝试运行此代码时，我总是从 scala.reflect.internal.FatalError: "package scala does not have a member Int" 收到错误消息.经过一番研究，我发现了这篇文章中描述的类似问题:

My problem is that I always get an error from scala.reflect.internal.FatalError: "package scala does not have a member Int", when trying to run this code. After some research I found similar problems described in this posts:

Scala 和 Play 2.0 插件更新 0.38.437 已发布

Scala 编译器错误:包 api 没有没有成员 materializeWeakTypeTag

我当前的 Scala 版本是 2.11.4，所以我尝试在我的build.sbt"文件中切换到不同的scala-compiler"和scala-library"版本，但是使用没有成功.就像在上面的帖子中提到的那样，它可能是 Scala 中的一个错误.我想知道是否有人对所描述的问题有解决方案或任何解决方法.

My current Scala version is 2.11.4, so I tried to switch to a different "scala-compiler" and "scala-library" versions in my "build.sbt" file, but with no success. Like it was mentioned in the posts above it is probably a bug in Scala. I wondered if somebody has a solution or perhaps any workaround for the described problem.

预先感谢您的任何帮助或建议.

Thanks in advance for any help or advice.

推荐答案

问题出在使用 Scala 和 Play Framework 2 的项目中的类路径中.可以通过将类路径从 SBT 填充到应用程序来解决:

The issue is in classpath in projects using Scala and Play Framework 2. It can be resolved by populating classpath from SBT to the application:

添加到 build.sbt 文件:

Add to build.sbt file:

val sbtcp = taskKey[Unit]("sbt-classpath")

sbtcp := {
  val files: Seq[File] = (fullClasspath in Compile).value.files
  val sbtClasspath : String = files.map(x => x.getAbsolutePath).mkString(":")
  println("Set SBT classpath to 'sbt-classpath' environment variable")
  System.setProperty("sbt-classpath", sbtClasspath)
}

compile  <<= (compile in Compile).dependsOn(sbtcp)

代码:

package controllers

import play.api.mvc.{Action, Controller}
import javax.script.ScriptEngineManager

class Interpreter extends Controller {

    val interpreter = new ScriptEngineManager().getEngineByName("scala")
    val settings = interpreter.asInstanceOf[scala.tools.nsc.interpreter.IMain].settings
    //settings.embeddedDefaults[Interpreter] // not need
    //settings.usejavacp.value = true // not need
    val sbtClasspath = System.getProperty("sbt-classpath")
    settings.classpath.value = s".:${sbtClasspath}" // <-- this line fix the problem

    def index = Action {
        Ok(views.html.interpreter())
    }

    def interpret(input: String) = Action { 
        implicit request => interpreter.eval("1 to 10 foreach println")
        Ok("Got: " + input)
    }
}

object Interpreter

在生产中应该使用另一个场景来获得正确的类路径.

In production should be used another scenario to get a correct classpath.

可能使用命令行中的-cp"或-classpath"键.

Probably using a '-cp' or '-classpath' key from the command line.

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