scala 为什么我不能执行scala文件？

Why I can't execute scala file?

提问by user1653363

I am a newbie to Scala, it's the first time I'm running Scala, when I installed Scala, I created a file named Hello.scala, the content is:

我是 Scala 的新手，这是我第一次运行 Scala，当我安装 Scala 时，我创建了一个名为 的文件Hello.scala，内容是：

println("HelloWorld!")

when I typed scala, there was no problem, the scala REPL was shown, but when I typed scala Hello.scala, it prompted:

当我输入时scala，没有问题，显示了scala REPL，但是当我输入时scala Hello.scala，它提示：

<console>:1: error: ';' expected but '.' is found.

I dont know what problem is, I hope someone can help me.

我不知道是什么问题，我希望有人可以帮助我。

回答by Mingyu

• Adding -ncflag saved my day.

  scala -nc Hello.scala

• What is -nc?

  -nc no compilation daemon: do not use the fsc offline compiler

  Source: http://alvinalexander.com/java/jwarehouse/scala-2.11/compiler/scala/tools/nsc/GenericRunnerCommand.scala.shtml

• What is fsc offline compiler?

  fsc – Fast offline compiler for the Scala 2 language

  Source: http://www.scala-lang.org/old/sites/default/files/linuxsoft_archives/docu/files/tools/fsc.html

• 添加-nc标志拯救了我的一天。

  scala -nc Hello.scala

• 什么是-nc？

  -nc no compilation daemon: do not use the fsc offline compiler

  来源：http: //alvinalexander.com/java/jwarehouse/scala-2.11/compiler/scala/tools/nsc/GenericRunnerCommand.scala.shtml

• 什么是fsc offline compiler？

  fsc – Fast offline compiler for the Scala 2 language

  来源：http: //www.scala-lang.org/old/sites/default/files/linuxsoft_archives/docu/files/tools/fsc.html

回答by om-nom-nom

To execute external script (load all definitions from it) in REPL use :load <filepath>command instead of scala <filepath>.

要在 REPL 中执行外部脚本（从中加载所有定义），请使用:load <filepath>命令而不是scala <filepath>.

? echo 'println("HelloWorld")' > Hello.scala
? scala
Welcome to Scala version 2.9.2 (OpenJDK Client VM, Java 1.6.0_24).
Type in expressions to have them evaluated.
Type :help for more information.

// is this what you tried to do?
scala> scala Hello.scala
<console>:1: error: ';' expected but '.' found.
   scala Hello.scala

// do this instead
scala> :load Hello.scala
Loading Hello.scala...
HelloWorld

scala>

回答by dhg

Your file Hello.scalais a script. You should be able to run it from the command prompt with scala Hello.scala.

您的文件Hello.scala是一个脚本。您应该能够从命令提示符运行它scala Hello.scala。

$ scala Hello.scala 
HelloWorld!

The REPL, on the other hand, is not for running scripts. It is used for running scala code directly:

另一方面，REPL 不用于运行脚本。它用于直接运行 Scala 代码：

scala> println("HelloWorld!")
"HelloWorld!"

回答by kiran Guntur

If you are executing it in scala REPL .You should be using as below

如果你在 scala REPL 中执行它。你应该使用如下

:load [scala file path]

output would be as below

输出如下

defined "objectname"

定义的“对象名”

Then invoke the main method as the next command

然后调用main方法作为下一个命令

objectname.main(Array())

Refer the below url for more detailed info

有关更多详细信息，请参阅以下网址

https://www.scala-lang.org/documentation/getting-started.html

https://www.scala-lang.org/documentation/getting-started.html

回答by vishwas vadavi

Write the printlnstatement inside the main function:

println在main函数里面写语句：

object HelloWorld {   
 def main(args: Array[String]) {   
   println("Hello World!")   
 }   
}

Then execute: scala -nc HelloWorld.scala

然后执行： scala -nc HelloWorld.scala

回答by wliao

Just a summary of what I know. I used to be confused by how to run a scala file properly.

只是我所知道的总结。我曾经对如何正确运行 Scala 文件感到困惑。

In sum, we got 3 ways to achieve this:

总之，我们有 3 种方法来实现这一点：

1. For script files. For script, it means it's just as the same as you type lines of statements in the REPL, or use :pastemode to paste multiple lines. Something like:

   println("foo")

2. Compile an object containing main method with scalac. You can extendsApp trait to easily implement.

   def main(args: Array[String]) : Unit

1. 对于脚本文件。对于脚本来说，就和你在 REPL 中键入语句行一样，或者使用:pastemode 粘贴多行。就像是：

   out.println("foo")

2. 编译一个包含 main 方法的对象scalac。您可以通过extendsApp trait 轻松实现。

   def main(args: Array[String]) : 单位

You may say "You liar, there are just two ways". But for the second one, I think there's too ways to get it running.

你可能会说“你这个骗子，只有两种方法”。但是对于第二个，我认为有太多方法可以让它运行。

1. scala -howtorun:object ObjectName -cp "./": The -cpis just for insurance.
2. java -cp "/path/to/your/scala-jars" ObjectName: So the difference is just the classpath need to be included.

1. scala -howtorun:object ObjectName -cp "./":-cp只是为了保险。
2. java -cp "/path/to/your/scala-jars" ObjectName: 所以区别只是需要包含类路径。

回答by nazar_art

If you're on some flavor of Unix, you can run a Scala script as a shell script by prepending a pound bangdirective at the top of the file.

如果您使用的是某种 Unix，您可以通过在文件顶部添加一个pound bang指令来将 Scala 脚本作为 shell 脚本运行。

For example, type the following into a file named helloarg:

例如，在名为 的文件中键入以下内容helloarg：

#!/bin/sh
exec scala "
$ chmod +x helloarg
" "$@"
!#
// Say hello to the first argument
println("Hello, "+ args(0) +"!")

The initial #!/bin/shmust be the very first line in the file.
Once you set its execute permission:

首字母#!/bin/sh必须是文件中的第一行。
一旦你设置了它的执行权限：

$ ./helloarg globe

You can run the Scala script as a shell script by simply saying:

您可以将 Scala 脚本作为 shell 脚本运行，只需说：

::#!
@echo off
call scala % 0 % *
goto :eof
::!#

If you're on Windows, you can achieve the same effect by naming the file helloarg.batand placing this at the top of your script:

如果您使用的是 Windows，您可以通过命名文件helloarg.bat并将其放在脚本顶部来实现相同的效果：

#!/usr/bin/env scala -nc
println("hello");

回答by Deepak

When you are trying to run scala follow below steps:

当您尝试运行 scala 时，请按照以下步骤操作：

1. Dont open scala REPL
2. use scala <filename.scala><Input if any>from cmd prompt

1. 不要打开scala REPL
2. 使用scala <filename.scala><Input if any>从命令提示符

below is the example:

下面是示例：

scala /home/prakash/Desktop/babyname.scala < /home/prakash/Desktop/ND

scala /home/prakash/Desktop/babyname.scala < /home/prakash/Desktop/ND

Note:above command must be typed in unix cmd prompt not in scala repl.

注意：以上命令必须在 unix cmd 提示符下输入，而不是在 scala repl 中。

回答by jichi

This works in mac for development.

这适用于 mac 进行开发。

##代码##