Scala 类文件与 Java 类文件

发布于 2024-09-12 05:27:32 字数 2472 浏览 8 评论 0原文

假设我有这个 Hello.scala。

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

我可以运行“scalac”来获取 HelloWorld.class 和 HelloWorld$.class。 我可以使用 'scala -classpath 运行。你好'。但我无法运行“java -cp”。你好'。

  • 这是为什么呢? scala 不能与 Java 互操作吗?
  • 有没有办法用Java运行scala的类?
  • 为什么 scalac 会生成两个类文件?
  • scala 有类似“lein uber”的东西吗?我的意思是,scala 是否有一些工具可以生成一个 jar 文件用于分发目的?

IntelliJ + scala 插件

我可以获得一个 jar,其中包含使用 IntelliJ + scala 插件运行 scala 文件的所有内容,我认为这是比 proguard 更好的选择。

proguard 设置

感谢 Moritz,我可以制作一个用 java 运行的 jar 文件。 这是整体结构。

|-- classes
|   |-- HelloWorld$.class
|   |-- HelloWorld.class
|   `-- META-INF
|       `-- MANIFEST.MF
`-- your.pro

your.pro 有以下内容。

-injar classes
-injar /Users/smcho/bin/scala/lib/scala-library.jar(!META-INF/MANIFEST.MF)
-outjar main.jar
-libraryjar /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Classes/classes.jar

-dontwarn
-dontnote
-ignorewarnings

-optimizationpasses 2
-optimizations !code/allocation/variable

-keep,allowoptimization,allowshrinking class * { *; }
-keepattributes SourceFile,LineNumberTable

-keepclasseswithmembers public class HelloWorld { public static void main(java.lang.String[]); }

MANIFEST.MF 有以下设置。不要忘记包含 [CR] 或空行。

Main-Class: HelloWorld

我下载了 proguard 4.5.1 将其放在 ~/bin/proguard4.5.1 中。 运行 proguard,我可以制作 jar (main.jar),并且它工作正常。

prosseek:classes smcho$ java -Xmx512m -jar /Users/smcho/bin/proguard4.5.1/lib/proguard.jar @your.pro

ProGuard, version 4.5.1
Reading program directory [/Users/smcho/Desktop/scala/proguard/classes/classes]
Reading program jar [/Users/smcho/bin/scala/lib/scala-library.jar] (filtered)
Reading library jar [/System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Classes/classes.jar]
Preparing output jar [/Users/smcho/Desktop/scala/proguard/classes/main.jar]
  Copying resources from program directory [/Users/smcho/Desktop/scala/proguard/classes/classes]
  Copying resources from program jar [/Users/smcho/bin/scala/lib/scala-library.jar] (filtered)
prosseek:classes smcho$ java -jar main.jar hello

java -cp main.jar HelloWorld

我上传示例 zip 文件 这里。并且,标量源代码此处

Let's say I have this Hello.scala.

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

I could run 'scalac' to get HelloWorld.class and HelloWorld$.class.
I can run using 'scala -classpath . Hello'. But I can't run 'java -cp . Hello'.

  • Why is this? Isn't scala interoperable with Java?
  • Is there any way to run scala's class with Java?
  • Why the scalac produces two class files?
  • Does scala have something like 'lein uber'? I mean, does scala have some tools that generates one jar file for distribution purposes?

IntelliJ + scala plugin

I could get a jar that contains everything to run scala file file with IntelliJ + scala plugin, I think this is the better option than proguard.

proguard setup

Thanks to Moritz, I could make one jar file that be run with java.
This is the overall structure.

|-- classes
|   |-- HelloWorld$.class
|   |-- HelloWorld.class
|   `-- META-INF
|       `-- MANIFEST.MF
`-- your.pro

your.pro has the following contents.

-injar classes
-injar /Users/smcho/bin/scala/lib/scala-library.jar(!META-INF/MANIFEST.MF)
-outjar main.jar
-libraryjar /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Classes/classes.jar

-dontwarn
-dontnote
-ignorewarnings

-optimizationpasses 2
-optimizations !code/allocation/variable

-keep,allowoptimization,allowshrinking class * { *; }
-keepattributes SourceFile,LineNumberTable

-keepclasseswithmembers public class HelloWorld { public static void main(java.lang.String[]); }

MANIFEST.MF has following setup. Don't forget to include [CR] or blank line.

Main-Class: HelloWorld

I download the proguard 4.5.1 to put it in ~/bin/proguard4.5.1.
Running proguard, I could make the jar (main.jar), and it works fine.

prosseek:classes smcho$ java -Xmx512m -jar /Users/smcho/bin/proguard4.5.1/lib/proguard.jar @your.pro

ProGuard, version 4.5.1
Reading program directory [/Users/smcho/Desktop/scala/proguard/classes/classes]
Reading program jar [/Users/smcho/bin/scala/lib/scala-library.jar] (filtered)
Reading library jar [/System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Classes/classes.jar]
Preparing output jar [/Users/smcho/Desktop/scala/proguard/classes/main.jar]
  Copying resources from program directory [/Users/smcho/Desktop/scala/proguard/classes/classes]
  Copying resources from program jar [/Users/smcho/bin/scala/lib/scala-library.jar] (filtered)
prosseek:classes smcho$ java -jar main.jar hello

or

java -cp main.jar HelloWorld

I upload the example zip file here. And, scalar source code here.

如果你对这篇内容有疑问,欢迎到本站社区发帖提问 参与讨论,获取更多帮助,或者扫码二维码加入 Web 技术交流群。

扫码二维码加入Web技术交流群

发布评论

需要 登录 才能够评论, 你可以免费 注册 一个本站的账号。

评论(1

可爱暴击 2024-09-19 05:27:32

您需要将 Scala 添加到类路径,例如

-classpath scala-library.jar:.

或通过添加

-Xbootclasspath/a:scala-library.jar

到 VM 参数。

补充:

抱歉,没有看到最后一个问题。如果您想分发单个 JAR 文件,许多人使用 ProGuard 从 scala 库传送所需的类。将您的课程与您的课程一起放在一个罐子中。

第二次编辑:

假设您有 .class 文件和 META-INF 文件夹,其中包含 MANIFEST.MF ,位于名为 classes 的文件夹中,您可以使用以下 Proguard 配置(调整路径后,例如,在 Linux/Windows 上您需要 rt.jar,而不是 Mac OS 上的 classes.jar),例如保存为 your.pro

-injar classes
-injar /opt/local/share/scala-2.8/lib/scala-library.jar(!META-INF/MANIFEST.MF)
-outjar main.jar
-libraryjar /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Classes/classes.jar

-dontwarn
-dontnote
-ignorewarnings

-optimizationpasses 2
-optimizations !code/allocation/variable

-keep,allowoptimization,allowshrinking class * { *; }
-keepattributes SourceFile,LineNumberTable

-keepclasseswithmembers public class your.Main { public static void main(java.lang.String[]); }

现在您可以创建main.jar

java -Xmx512m -jar proguard.jar @your.pro

最终您必须将-Xmx设置得更高一些。如需了解更多信息,请访问 SBT Wiki

You need to add Scala to the classpath, e.g.

-classpath scala-library.jar:.

or by adding

-Xbootclasspath/a:scala-library.jar

to the VM arguments.

Addition:

Sorry, did not see that last question. If you want do distribute single JAR files many people use ProGuard to ship the classes needed from the scala-library.jar along with your classes in one jar.

Second Edit:

Assuming you have your .class-files and your META-INF folder containing the MANIFEST.MF in a folder called classes you can use the following Proguard configuration (after adjusting the paths, e.g. you need rt.jar on Linux/Windows instead of classes.jar on Mac OS) saved e.g. as your.pro:

-injar classes
-injar /opt/local/share/scala-2.8/lib/scala-library.jar(!META-INF/MANIFEST.MF)
-outjar main.jar
-libraryjar /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Classes/classes.jar

-dontwarn
-dontnote
-ignorewarnings

-optimizationpasses 2
-optimizations !code/allocation/variable

-keep,allowoptimization,allowshrinking class * { *; }
-keepattributes SourceFile,LineNumberTable

-keepclasseswithmembers public class your.Main { public static void main(java.lang.String[]); }

Now you can create main.jar with

java -Xmx512m -jar proguard.jar @your.pro

Eventually you have to set the -Xmx a bit higher. Some more info can be found on the SBT Wiki.

~没有更多了~
我们使用 Cookies 和其他技术来定制您的体验包括您的登录状态等。通过阅读我们的 隐私政策 了解更多相关信息。 单击 接受 或继续使用网站,即表示您同意使用 Cookies 和您的相关数据。
原文