GraalVM -在类路径上没有语言和多标记实现。
GraalVM -在类路径上没有语言和多标记实现。
提问于 2019-06-22 02:36:19
我试图在项目中使用GraalVM来添加简单的脚本功能。我使用Maven进行依赖关系管理来加载Graal的基本依赖项。这是我的pom.xml：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>cx.matthew</groupId>
<artifactId>graaltest</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<graalvm.version>19.0.2</graalvm.version>
<compiler.dir>${project.build.directory}/compiler</compiler.dir>
<maven.compiler.source>1.6</maven.compiler.source>
<maven.compiler.target>1.6</maven.compiler.target>
</properties>
<repositories>
<repository>
<snapshots>
<enabled>false</enabled>
</snapshots>
<id>central</id>
<name>Maven Repository Switchboard</name>
<url>http://repo1.maven.org/maven2</url>
</repository>
<repository>
<id>papermc</id>
<url>https://papermc.io/repo/repository/maven-public/</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>org.graalvm.sdk</groupId>
<artifactId>graal-sdk</artifactId>
<version>${graalvm.version}</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.graalvm.js</groupId>
<artifactId>js</artifactId>
<version>${graalvm.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.graalvm.js</groupId>
<artifactId>js-scriptengine</artifactId>
<version>${graalvm.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.graalvm.tools</groupId>
<artifactId>profiler</artifactId>
<version>${graalvm.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.graalvm.tools</groupId>
<artifactId>chromeinspector</artifactId>
<version>${graalvm.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.graalvm.truffle</groupId>
<artifactId>truffle-api</artifactId>
<version>19.0.0</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>com.destroystokyo.paper</groupId>
<artifactId>paper-api</artifactId>
<version>1.14.2-R0.1-SNAPSHOT</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.2.1</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>下面是我调用Graal的代码：
package cx.matthew.graaltest;
import org.bukkit.plugin.java.JavaPlugin;
import org.graalvm.polyglot.Context;
public class GraalTestPlugin extends JavaPlugin {
@Override
public void onEnable() {
Context context = Context.create();
context.eval("js", "console.log(\"hi!!!\");");
}
}虽然据我所知，这应该是可行的，但在运行它时，它会输出以下错误：
[19:25:16 ERROR]: Error occurred while enabling GraalTest v1.0-SNAPSHOT (Is it up to date?)
java.lang.IllegalStateException: No language and polyglot implementation was found on the classpath. Make sure the truffle-api.jar is on the classpath.
at org.graalvm.polyglot.Engine$PolyglotInvalid.noPolyglotImplementationFound(Engine.java:800) ~[?:?]
at org.graalvm.polyglot.Engine$PolyglotInvalid.buildEngine(Engine.java:732) ~[?:?]
at org.graalvm.polyglot.Engine$Builder.build(Engine.java:505) ~[?:?]
at org.graalvm.polyglot.Context$Builder.build(Context.java:1304) ~[?:?]
at org.graalvm.polyglot.Context.create(Context.java:697) ~[?:?]
at cx.matthew.graaltest.GraalTestPlugin.onEnable(GraalTestPlugin.java:10) ~[?:?]
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:263) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:338) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:419) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.enablePlugin(CraftServer.java:464) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.enablePlugins(CraftServer.java:378) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.reload(CraftServer.java:854) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.Bukkit.reload(Bukkit.java:610) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:54) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:159) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.dispatchCommand(CraftServer.java:736) ~[patched_1.14.2.jar:git-Paper-97]
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.dispatchServerCommand(CraftServer.java:698) ~[patched_1.14.2.jar:git-Paper-97]
at net.minecraft.server.v1_14_R1.DedicatedServer.handleCommandQueue(DedicatedServer.java:457) ~[patched_1.14.2.jar:git-Paper-97]
at net.minecraft.server.v1_14_R1.DedicatedServer.b(DedicatedServer.java:419) ~[patched_1.14.2.jar:git-Paper-97]
at net.minecraft.server.v1_14_R1.MinecraftServer.a(MinecraftServer.java:1061) ~[patched_1.14.2.jar:git-Paper-97]
at net.minecraft.server.v1_14_R1.MinecraftServer.run(MinecraftServer.java:905) ~[patched_1.14.2.jar:git-Paper-97]
at java.lang.Thread.run(Thread.java:834) [?:?]当然，正如错误描述的那样，建议的解决方案是将块菌api.jar包含在类路径中，但是，由于这是在插件环境中运行的，因此让这个插件的最终用户手动设置类路径并不理想。松露-api Maven依赖项中的阴影似乎不起作用，这通常是解决此类问题的方法。
已经提出了一些现有的解决办法。我遇到的第一个例子是在这个答案中，但是正如您在我的pom.xml中看到的那样，所有这些依赖项都已经包括在内。
我看到的另一个解决方案(以及问题)是在这个GitHub问题中概述的，但是虽然我可以确认修改后的META/块菌/语言文件在我的最后一个jar中，但它似乎不起作用。这是jar中输出的文件：
language1.characterMimeType.0=application/tregex
language1.className=com.oracle.truffle.regex.RegexLanguage
language1.id=regex
language1.implementationName=
language1.interactive=false
language1.internal=true
language1.name=REGEX
language1.version=0.1
language2.characterMimeType.0=application/javascript
language2.characterMimeType.1=application/javascript+module
language2.characterMimeType.2=text/javascript
language2.className=com.oracle.truffle.js.lang.JavaScriptLanguage
language2.defaultMimeType=application/javascript
language2.dependentLanguage.0=regex
language2.fileTypeDetector0=com.oracle.truffle.js.lang.JSFileTypeDetector
language2.id=js
language2.implementationName=GraalVM JavaScript
language2.interactive=true
language2.internal=false
language2.name=JavaScript
language2.version=inherit所以，我现在有点不知所措。有没有人对如何解决这个问题有任何想法？
回答 1
Stack Overflow用户
回答已采纳
发布于 2019-06-23 00:03:34
到目前为止，我找到的最佳解决方法是将上下文ClassLoader替换为正确的上下文，然后将其交换回来：
ClassLoader oldCl = Thread.currentThread().getContextClassLoader();
Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
// Insert Graal code here
Thread.currentThread().setContextClassLoader(oldCl);您甚至可以将其设置为回调，这样就不必重复使用相同的代码了：
private void runInPluginContext(ContextCallback callback) {
ClassLoader oldCl = Thread.currentThread().getContextClassLoader();
Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
callback.call();
Thread.currentThread().setContextClassLoader(oldCl);
}
interface ContextCallback {
void call();
}并使用以下方法运行：
runInPluginContext(() -> {
// Insert Graal code here
});显然，这并不理想，因为每次调用Graal代码时都需要更改上下文。如果有人有更好的解决方案，我很乐意看到！
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/56712178
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