scala.tools.reflect.ToolBoxError:反射编译失败:由于java.lang.VerifyError而无法初始化编译器

问题描述

我想传递一个包含案例类的scala文件，以便我的应用程序在运行时编译该案例类并开始使用它.

I want to pass a scala file containing a case class so my application compiles this case class during run time and start using it.

我这样做的主要原因是因为我希望避免每次case类更改时都重新构建代码.因此最好将其作为参数传递(以防万一，使用这种case类的操作是通用的，因此在转换中不需要任何重做)

The main reason why I am doing this is because I want to avoid rebuilding my code every time the case class changes. So would be better to pass it as a parameter (in case you are wondered, the operations with this case class are generic so it is not required any rework in the transformations)

我正在使用这些 post1 ，和 post3 作为参考.到目前为止，我的应用程序如下所示:

I was using these post1, post2 and post3 as references. So far my application looks like this:

import scala.io.Source
import scala.reflect.runtime.universe
import scala.tools.reflect._

object TestCompile {
  def main(args: Array[String]): Unit = {

    val path = "C:\\myWorkspace\\entity\\TestClass.scala"
    val tb = universe.runtimeMirror(getClass.getClassLoader).mkToolBox()
    val src = Source.fromFile(path).mkString.stripMargin
    val clazz = tb.compile(tb.parse(src))().asInstanceOf[Class[_]]

  }
}

文件 TestClass.scala 如下:

case class TestClass(
         val value : String,
         val timeStamp : Long,
         val rowKey : String,
         val columnFamily : String
)

但是我要例外了

val clazz = tb.compile(tb.parse(src))().asInstanceOf[Class[_]]

例外:

以下是我正在使用的依赖项，但是我尝试将其他版本始终得到相同的错误:

Below is the dependency I am using, however I tried with other versions always getting the same error:

<dependency>
  <groupId>org.scala-lang</groupId>
  <artifactId>scala-reflect</artifactId>
  <version>2.11.6</version>
</dependency>

我在做什么错了?

推荐答案

我今天有一些时间对此进行测试.我认为主要问题是 TestClass.scala 中缺少最后一个预期行scala.reflect.classTag[TestClass].runtimeClass.

I got some time to test this today. The main problem I think is that the last expected line scala.reflect.classTag[TestClass].runtimeClass is missing in TestClass.scala.

要记住的另一件重要事情是，scala-compiler.jar也应该在您的类路径中.

One other important thing to remember is that scala-compiler.jar should also be in your class path.

一旦我解决了这个问题，我就遇到了Java/Scala对象转换的另一个问题.您有两个选择，将timeStamp字段设置为String或Java.lang.Long.由于String转换是微不足道的，因此下面给出了Java.lang.Long的示例.

Once I resolved that, I ran into another problem with Java/Scala object conversion. You have two options, make the timeStamp field, either a String or Java.lang.Long. Since the String conversion is trivial, I've given below example for Java.lang.Long.

进行上述更改后，我的 TestClass.scala 如下所示:

With the above changes, my TestClass.scala looks like below:

case class TestClass(
                      value : String,
                      timeStamp : java.lang.Long,
                      rowKey : String,
                      columnFamily : String
                    ) {}

scala.reflect.classTag[TestClass].runtimeClass

我将其复制到/tmp/目录进行测试.

I copied it to /tmp/ directory for testing.

我的 TestCompile.scala 如下所示:

import scala.io.Source
import scala.reflect.runtime.universe
import scala.tools.reflect._

object TestCompile {
  def main(args: Array[String]): Unit = {

    val path = "/tmp/TestClass.scala"
    val tb = universe.runtimeMirror(getClass.getClassLoader).mkToolBox()
    val src = Source.fromFile(path).mkString.stripMargin
    println(src)
    val clazz = tb.compile(tb.parse(src))().asInstanceOf[Class[_]]

    val ctor = clazz.getDeclaredConstructors()(0)
    val instance = ctor.newInstance("My value", new java.lang.Long(1234567890L), "Row1", "Column1")
    println(instance.toString)

  }
}

输出

TestClass(My value,1234567890,Row1,Column1)

这篇关于scala.tools.reflect.ToolBoxError:反射编译失败:由于java.lang.VerifyError而无法初始化编译器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！