Java 脚本 API 无法按名称检索引擎

Question

我正在尝试使用 Java 脚本 API 查找已安装的脚本引擎，但出了点问题。

在这个演示程序中，我使用 ScriptEngineManager 来检索工厂并列出我拥有的所有引擎。之后我尝试通过名称获取它，但结果为空。

 public class App {
  public static void main(String[] args) {
    ScriptEngineManager manager = new ScriptEngineManager();
    List<ScriptEngineFactory> factories = manager.getEngineFactories();

    for (ScriptEngineFactory factory : factories) {
        System.out.println("\nName : " + factory.getEngineName());
        System.out.println("Version : " + factory.getEngineVersion());
        System.out.println("Language name : " + factory.getLanguageName());
        System.out.println("Language version : " + factory.getLanguageVersion());
        System.out.println("Extensions : " + factory.getExtensions());
        System.out.println("Mime types : " + factory.getMimeTypes());
        System.out.println("Names : " + factory.getNames());
        ScriptEngine engine = manager.getEngineByName(factory.getEngineName());
        if (engine == null) {
            System.out.println("Impossible to find the engine with name " + factory.getEngineName()+"\n");
        }

    }
   }
 }

结果是：

Version : 1.7 release 3 PRERELEASE

Language name : ECMAScript

Language version : 1.8

Extensions : [js]

Mime types : [application/javascript, application/ecmascript, text/javascript, text/ecmascript]

Names : [js, rhino, JavaScript, javascript, ECMAScript, ecmascript]

Impossible to find the engine with name Mozilla Rhino

Name : jython

Version : 2.7.0

Language name : python

Language version : 2.7

Extensions : [py]

Mime types : [text/python, application/python, text/x-python, application/x-python]

Names : [python, jython]

Impossible to find the engine with name jython

Answer 1

查看ScriptEngineFactory的getnames()方法的文档：

Returns an immutable list of short names for the ScriptEngine, which may be used to identify the ScriptEngine by the ScriptEngineManager.

也就是说，必须使用以下名称之一：

...
System.out.println("Names : " + factory.getNames());
ScriptEngine engine = manager.getEngineByName(factory.getNames().get(0));
...

Java 脚本 API 无法按名称检索引擎

Java scripting API fails to retrieve engine by name

java

scripting

jython

rhino