在Scala中从JAR加载文件

import java.io.File
import java.io.FileOutputStream
import java.io.IOException
import java.io.OutputStreamWriter
import java.net.URL
import java.net.URLClassLoader
import java.util.jar.JarEntry
import java.util.jar.JarFile

object ScalaClassLoader {
  def main(args: Array[String]): Unit = {
    val jarFile = new File("example.jar")
    val classLoader = new URLClassLoader(new URL[] { jarFile.toURL })
    val className = "com.example.MyClass"
    val manifest = getClassManifest(classLoader)
    val classBytes = manifest.getMainAttributes.getValue("Class-Path")
    val classLoader = new URLClassLoader(new URL[]{jarFile.toURL}, classLoader)
    val myClass = classLoader.loadClass(className)
    val instance = myClass.newInstance
    instance.asInstanceOf[MyClass].myMethod()
  }

  def getClassManifest(classLoader: ClassLoader): Manifest = {
    val manifestFile = new File("MANIFEST.MF")
    if (manifestFile.exists) {
      val manifestStream = new FileInputStream(manifestFile)
      val manifest = new Manifest
      manifest.read(manifestStream)
      manifestStream.close()
      manifest
    } else {
      throw new IOException("Manifest file not found")
    }
  }
}

class MyClass {
  def myMethod(): Unit = {
    println("Hello from MyClass")
  }
}