getEngineByName（" nashorn"）返回null [英] getEngineByName("nashorn") returns null

问题描述

无法获得Nashorn引擎

Cant get Nashorn engine

ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
engine.eval("print('Hello World!');");

engine 返回 null

我使用的是eclipse，jdk1.8.0_11

I am using eclipse, jdk1.8.0_11

java -version

java版1.8.0_20-ea

java version "1.8.0_20-ea"

Java（TM）SE运行时环境（版本1.8.0_20-ea-b23）

Java(TM) SE Runtime Environment (build 1.8.0_20-ea-b23)

推荐答案

当我传递null时它正在工作param into ScriptEngineManager构造函数：

Its working when I pass null param into ScriptEngineManager constructor:

ScriptEngine engine = new ScriptEngineManager(null).getEngineByName("nashorn");
engine.eval("print('Hello World!');");

来自java docs

from java docs

ScriptEngineManager（ClassLoader） loader）

ScriptEngineManager(ClassLoader loader)

如果loader为null，则会加载与平台捆绑在一起且在通常的扩展目录（已安装的扩展名）中的脚本引擎工厂。

If loader is null, the script engine factories that are bundled with the platform and that are in the usual extension directories (installed extensions) are loaded.

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