java - Groovy，嵌入Java，回调Java

Question

我知道我必须做一些脑残愚蠢的事情才能使它不起作用，但我处于一种情况，我想将行为动态加载到正在运行的服务器中。我选择 groovy 作为我的工具来做到这一点。该行为将需要引用服务器类路径上的类，例如我的模型对象以及第三方库，例如 Freemarker。

我把这个愚蠢的 POC 放在一起来展示可行性。我无法获取 groovy 脚本来解析 Java 类“ThingyDoodle”和“Fooable”，尽管我将 GroovyClassPath 的父类路径设置为当前类路径。

public class GroovyTest
{
    public static void main ( String [ ] argv ) throws Throwable
    {
            // Setting parent classloader!
            // also tried plain old "GroovyTest.class.getClassLoader()" as well
        GroovyClassLoader gcl = new GroovyClassLoader ( Thread.currentThread().getContextClassLoader() ) ;
        String src =
              "class Arf implements Fooable {
                 public String foo ( ) {
                   return new ThingyDoodle().doStuff('Arf');}}" ;
        Class clazz = gcl.parseClass(src, "AppleSauce.groovy");
        Object aScript = clazz.newInstance();
        Fooable myObject = (Fooable) aScript;
        System.out.println ( myObject.foo() ) ;
    }

    public static interface Fooable { public String foo ( ) ; }

    public static class ThingyDoodle
    {
        public String doStuff ( String input )
        {
            return "Hi Worlds" ;
        }
    }
}

我到底做错了什么？

Exception in thread "main" org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
AppleSauce.groovy: 1: unable to resolve class Fooable
 @ line 1, column 1.
   class Arf implements Fooable { public String foo ( ) { return new ThingyDoodle().doStuff('Arf');}}
   ^

AppleSauce.groovy: 1: unable to resolve class ThingyDoodle
 @ line 1, column 63.
   ublic String foo ( ) { return new Thingy
                                     ^

Answer 1

您的代码中的问题是无法找到 Fooable 接口(interface)和 ThingyDoodle 类，因为它们都是内部类，需要使用包含的类名进行限定，即 GroovyTest。我在嵌入式脚本中限定了两个名称(并修复了脚本周围的引号)并且它按预期运行。

import groovy.lang.GroovyClassLoader;

public class GroovyTest
{

    public static void main ( String [ ] argv ) throws Throwable
    {
            // Setting parent classloader!
            // also tried plain old "GroovyTest.class.getClassLoader()" as well
        GroovyClassLoader gcl = new GroovyClassLoader ( Thread.currentThread().getContextClassLoader() ) ;
        String src =
              "class Arf implements GroovyTest.Fooable { " + 
                 "public String foo ( ) { " + 
                   "return new GroovyTest.ThingyDoodle().doStuff('Arf');}}" ;
        Class clazz = gcl.parseClass(src, "AppleSauce.groovy");
        Object aScript = clazz.newInstance();
        Fooable myObject = (Fooable) aScript;
        System.out.println ( myObject.foo() ) ;
    }       
     public static interface Fooable { public String foo ( ) ; }

    public static class ThingyDoodle
    {
        public String doStuff ( String input )
        {
            return "Hi Worlds" ;
        }
    }


}