如何使用graaljs？是否有放置.jar文件的地方？

Question

我使用Java 8，并且使用默认的JavaScript引擎（Nashorn）。

我想看看它与“高度宣传”的GRAAL JS相比如何。看到：

• https://github.com/graalvm/graaljs
• https://www.graalvm.org/

特别是因为我听说他们想弃用nashorn：

• http://openjdk.java.net/jeps/335

有人知道如何（轻松）访问graaljs吗？我希望找到一个pom.xml或一个下载jar文件但不走运的地方

Answer 1

目前，在GraalVM之外没有可用的预先构建的Graal.js jar。要在其他JDK上运行它，可以从GraalVM中提取jar或按以下方式html" target="_blank">构建它：

$ git clone [e-mail]:graalvm/graaljs.git
$ git clone [e-mail]:graalvm/mx.git
$ export PATH=$PWD/mx:$PATH
$ export JAVA_HOME=/usr/java/jdk1.8.0_161
$ cd graaljs/graal-js
$ mx build

请注意，它可以用JDK 8很好地构建。它也可以在JDK 8上运行：

$ mx js
> typeof([] + 1)
string
>

外壳程序有效，Ctrl+ D退出。-v前一个命令行中的选项显示了如何启动它：

$ mx -v js
...
env JAVA_HOME=/usr/java/jdk1.8.0_161 ... \
/usr/java/jdk1.8.0_161/bin/java -d64 -cp /tmp/graal-js/graal/sdk/mxbuild/dists/graal-sdk.jar:/tmp/graal-js/graal/truffle/mxbuild/dists/truffle-api.jar:/tmp/graal-js/graal/tools/mxbuild/dists/truffle-profiler.jar:/tmp/graal-js/graal/tools/mxbuild/dists/chromeinspector.jar:/tmp/graal-js/graal/sdk/mxbuild/dists/launcher-common.jar:/tmp/graal-js/graaljs/graal-js/mxbuild/dists/graaljs-launcher.jar:/tmp/graal-js/graal/regex/mxbuild/dists/tregex.jar:/home/gmdubosc/.mx/cache/ASM_DEBUG_ALL_702b8525fcf81454235e5e2fa2a35f15ffc0ec7e.jar:/home/gmdubosc/.mx/cache/ICU4J_6f06e820cf4c8968bbbaae66ae0b33f6a256b57f.jar:/tmp/graal-js/graaljs/graal-js/mxbuild/dists/graaljs.jar -Dtruffle.js.BindProgramResult=false -Xms2g -Xmx2g -Xss16m com.oracle.truffle.js.shell.JSLauncher

因此，它将这些罐子放在类路径中：

• /tmp/graal-js/graal/sdk/mxbuild/dists/graal-sdk.jar
• /tmp/graal-js/graal/truffle/mxbuild/dists/truffle-api.jar
• /tmp/graal-js/graal/tools/mxbuild/dists/truffle-profiler.jar
• /tmp/graal-js/graal/tools/mxbuild/dists/chromeinspector.jar
• /tmp/graal-js/graal/sdk/mxbuild/dists/launcher-common.jar
• /tmp/graal-js/graaljs/graal-js/mxbuild/dists/graaljs-launcher.jar
• /tmp/graal-js/graal/regex/mxbuild/dists/tregex.jar
• /home/gmdubosc/.mx/cache/ASM_DEBUG_ALL_702b8525fcf81454235e5e2fa2a35f15ffc0ec7e.jar
• /home/gmdubosc/.mx/cache/ICU4J_6f06e820cf4c8968bbbaae66ae0b33f6a256b57f.jar
• /tmp/graal-js/graaljs/graal-js/mxbuild/dists/graaljs.jar

查看构建工件，我们还可以看到mxbuild/dists/graaljs-scriptengine.jar哪个负责向脚本引擎API注册Graal.js。

使用一个小的测试文件：

import javax.script.*;
import java.util.Arrays;
public class Test {
  public static void main(String... args) throws ScriptException {
    ScriptEngineManager manager = new ScriptEngineManager();
    for (ScriptEngineFactory factory : manager.getEngineFactories()) {
      System.out.printf("%s %s: %s %s%n", factory.getLanguageName(), factory.getLanguageVersion(), factory.getEngineName(), factory.getNames());
    }
    ScriptEngine engine = manager.getEngineByName("Graal.js");
    if (engine != null) {
      Object result = engine.eval("typeof([] + 1)");
      System.out.println(result);
    }
  }
}

在库存JDK 8上进行编译和运行可以得到：

$ javac Test.java
$ java -cp . Test
ECMAScript ECMA - 262 Edition 5.1: Oracle Nashorn [nashorn, Nashorn, js, JS, JavaScript, javascript, ECMAScript, ecmascript]

现在在类路径上使用Graal.js：

$ java -cp /tmp/graal-js/graal/sdk/mxbuild/dists/graal-sdk.jar:/tmp/graal-js/graal/truffle/mxbuild/dists/truffle-api.jar:/tmp/graal-js/graal/regex/mxbuild/dists/tregex.jar:/home/gmdubosc/.mx/cache/ASM_DEBUG_ALL_702b8525fcf81454235e5e2fa2a35f15ffc0ec7e.jar:/home/gmdubosc/.mx/cache/ICU4J_6f06e820cf4c8968bbbaae66ae0b33f6a256b57f.jar:/tmp/graal-js/graaljs/graal-js/mxbuild/dists/graaljs.jar:/tmp/graal-js/graaljs/graal-js/mxbuild/dists/graaljs-scriptengine.jar:. Test
ECMAScript ECMA - 262 Edition 6: Graal.js [Graal.js, graal.js, Graal-js, graal-js, Graal.JS, Graal-JS, GraalJS, GraalJSPolyglot, js, JS, JavaScript, javascript, ECMAScript, ecmascript]
ECMAScript ECMA - 262 Edition 5.1: Oracle Nashorn [nashorn, Nashorn, null, null, null, null, null, null]
string

（请注意，此命令行忽略truffle-profiler，chromeinspector，launcher-common和graaljs- launcher其中通过脚本引擎使用Graal.js时不是必需的。）

由于标准JDK 8不支持JVMCI和/或Graal编译器，因此将没有用于JS的JIT编译，因此不要对性能抱有太大期望。为了获得性能，您需要特殊的JDK
8或JDK 9+以及Graal-Truffle绑定。