Question

我有以下hello.scala文件：

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

使用scalac进行编译后，我会回来hello.class和hello$.class。

如何使用java命令执行它？我应该把???放在哪里？

$ java ??? hello

Answer 1

使用scala命令运行它。即scala hello

Answer 2

您正在寻找

java -cp /wherever/my/scala/lives/lib/scala-library.jar hello

或者你可以

scala hello

Answer 3

我认为可能是时候向用户介绍另一种可以轻松开发Scala应用程序的工具 - 编译源代码，构建具有所有依赖关系的单jar工件等。我不认为单个object hello应用程序是OP在Scala中开发的最后一个词，也是最终需要的工具。

话虽如此，我强烈建议使用项目构建工具并且sbt可能非常合适。

从the sbt project's web site下载sbt启动程序，并在sbt对象所在的目录中运行hello。

要运行hello对象，请执行sbt并让它执行其他命令 - 其中run是运行hello对象应用程序的命令。

jacek:~/sandbox/so/hello-object
$ sbt
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Updating {file:/Users/jacek/.sbt/0.13/plugins/}global-plugins...
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[info] Done updating.
[info] Set current project to hello-object (in build file:/Users/jacek/sandbox/so/hello-object/)
[hello-object]> run
[info] Updating {file:/Users/jacek/sandbox/so/hello-object/}hello-object...
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[info] Done updating.
[info] Compiling 1 Scala source to /Users/jacek/sandbox/so/hello-object/target/scala-2.10/classes...
[info] Running hello
Hello World!
[success] Total time: 12 s, completed Mar 16, 2014 2:32:39 PM

如果您需要知道run hello对象的命令行到底是什么，请执行last或last run以明确并打印部件出你的。

[hello-object]> last
[debug]
[debug] Initial source changes:
[debug]     removed:Set()
[debug]     added: Set()
[debug]     modified: Set()
[debug] Removed products: Set()
[debug] External API changes: API Changes: Set()
[debug] Modified binary dependencies: Set()
[debug] Initial directly invalidated sources: Set()
[debug]
[debug] Sources indirectly invalidated by:
[debug]     product: Set()
[debug]     binary dep: Set()
[debug]     external source: Set()
[debug] All initially invalidated sources: Set()
[debug] Copy resource mappings:
[debug]
[info] Running hello
[debug] Waiting for threads to exit or System.exit to be called.
[debug]   Classpath:
[debug]     /Users/jacek/sandbox/so/hello-object/target/scala-2.10/classes
[debug]     /Users/jacek/.sbt/boot/scala-2.10.3/lib/scala-library.jar
[debug] Waiting for thread run-main-3 to terminate.
[debug]     Thread run-main-3 exited.
[debug] Interrupting remaining threads (should be all daemons).
[debug] Sandboxed run complete..
[debug] Exited with code 0
[success] Total time: 0 s, completed Mar 16, 2014 2:41:57 PM
[debug] > shell

Classpath之后的Running hello部分是您需要的 - 运行hello对象的类路径。

jacek:~/sandbox/so/hello-object
$ java -cp /Users/jacek/sandbox/so/hello-object/target/scala-2.10/classes:/Users/jacek/.sbt/boot/scala-2.10.3/lib/scala-library.jar hello
Hello World!

一旦您对Scala开发的结果感到满意并且应用程序已准备好进行生产部署，请执行package为其他项目创建一个jar文件（甚至是Java项目）。< / p>

[hello-object]> package
[info] Packaging /Users/jacek/sandbox/so/hello-object/target/scala-2.10/hello-object_2.10-0.1-SNAPSHOT.jar ...
[info] Done packaging.
[success] Total time: 1 s, completed Mar 16, 2014 2:34:34 PM

您可能希望将其发布到Ivy2（默认）或带有publishLocal的Maven存储库，以便其他Scala / Java / JRuby / Groovy项目可以使用它。

[hello-object]> publishLocal
[info] Packaging /Users/jacek/sandbox/so/hello-object/target/scala-2.10/hello-object_2.10-0.1-SNAPSHOT-sources.jar ...
[info] Done packaging.
[info] Wrote /Users/jacek/sandbox/so/hello-object/target/scala-2.10/hello-object_2.10-0.1-SNAPSHOT.pom
[info] :: delivering :: default#hello-object_2.10;0.1-SNAPSHOT :: 0.1-SNAPSHOT :: integration :: Sun Mar 16 14:35:57 CET 2014
[info]  delivering ivy file to /Users/jacek/sandbox/so/hello-object/target/scala-2.10/ivy-0.1-SNAPSHOT.xml
[info] Main Scala API documentation to /Users/jacek/sandbox/so/hello-object/target/scala-2.10/api...
model contains 2 documentable templates
[info] Main Scala API documentation successful.
[info] Packaging /Users/jacek/sandbox/so/hello-object/target/scala-2.10/hello-object_2.10-0.1-SNAPSHOT-javadoc.jar ...
[info] Done packaging.
[info]  published hello-object_2.10 to /Users/jacek/.ivy2/local/default/hello-object_2.10/0.1-SNAPSHOT/poms/hello-object_2.10.pom
[info]  published hello-object_2.10 to /Users/jacek/.ivy2/local/default/hello-object_2.10/0.1-SNAPSHOT/jars/hello-object_2.10.jar
[info]  published hello-object_2.10 to /Users/jacek/.ivy2/local/default/hello-object_2.10/0.1-SNAPSHOT/srcs/hello-object_2.10-sources.jar
[info]  published hello-object_2.10 to /Users/jacek/.ivy2/local/default/hello-object_2.10/0.1-SNAPSHOT/docs/hello-object_2.10-javadoc.jar
[info]  published ivy to /Users/jacek/.ivy2/local/default/hello-object_2.10/0.1-SNAPSHOT/ivys/ivy.xml
[success] Total time: 4 s, completed Mar 16, 2014 2:36:01 PM

最后但并非最不重要的是 - 让一个包含所有依赖项的jar使用sbt-assembly插件。

Answer 4

另一种方法是，调用例如hello.sh的文件，将其设置为可执行文件，

chmod +x hello.sh

注意文件的标题，

#!/bin/sh
exec scala -savecompiled "$0" "$@"
!#

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

使用

简单地运行它

./hello.sh

开关-savecompiled在第一次执行时创建一个JAR文件，执行后启动会更快，因为不需要（重新）编译脚本代码。

如何在命令行中运行Scala编译代码？

4 个答案: