Groovy，嵌入Java，调用Java

我知道我必须做一些愚蠢至极的事情才能让它不起作用，但我现在的处境是，我想动态地将行为加载到正在运行的服务器中。我选择groovy作为我的工具来实现这一点。该行为将需要引用服务器类路径上的类，比如我的模型对象以及第三方库，比如Freemarker

我拼凑了这个愚蠢的POC来证明它的可行性。我无法让groovy脚本解析Java类“ThingyDoodle”和“Fooable”，尽管我将GroovyClassPath的父类路径设置为当前路径

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
                                     ^

---

不知道你是怎么编译的。。。我尝试了这个（作为构建工具使用），它很有效

/build.gradle

apply plugin:'application'

repositories {
    mavenCentral()
}

dependencies {
    compile group: 'org.codehaus.groovy', name: 'groovy', version: '1.8.6'
}

mainClassName = 'org.timyates.GroovyTest'

./src/main/java/org/timyates/Fooable.java

package org.timyates ;

public interface Fooable {
  public String foo() ;
}

./src/main/java/org/timyates/ThingyDoodle.java

package org.timyates ;

public class ThingyDoodle {
  public String doStuff( String input ) {
    return String.format( "Hi %s", input ) ;
  }
}

./src/main/java/org/timyates/GroovyTest.java

package org.timyates ;

import groovy.lang.GroovyClassLoader ;

public class GroovyTest {
  public static void main( String[] args ) throws Exception {
    GroovyClassLoader gcl = new GroovyClassLoader( GroovyTest.class.getClassLoader() ) ;
    String src = "import org.timyates.*\n" +
                 "class Arf implements Fooable {\n" +
                 "  public String foo() {\n" +
                 "    new ThingyDoodle().doStuff( 'tim' )\n" +
                 "  }\n" +
                 "}" ;
    Class clazz = gcl.parseClass( src, "AppleSauce.groovy" ) ;
    Fooable myObject = (Fooable)clazz.newInstance() ;
    System.out.println( myObject.foo() ) ;
  }
}

然后，当我在命令行中输入

gradlerun

时，我会得到以下输出：

$ gradle run
:compileJava
:processResources UP-TO-DATE
:classes
:run
Hi tim

BUILD SUCCESSFUL

---

代码中的问题是找不到Fooable接口和ThingyDoodle类，因为它们都是内部类，需要使用包含的类名限定，即GroovyTest。我在嵌入的脚本中限定了这两个名称（并修复了脚本周围的引号），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" ;
        }
    }


}

---

非常感谢你！这就是我需要的，别担心。我擅长发现别人的缺点，但对自己的缺点视而不见我在运行时在J2EE服务器中内联编译它。如果我使用gradle，它将无法达到此练习的目的。无论如何谢谢你！很公平，很高兴它被分类了：-）把这类信息放在问题中可能会节省下一次的时间；-）祝你好运！