从java调用groovy

需要将groovy-2.4.3.jar加入到classpath中

一：在java中用GroovyClassLoader执行groovy代码

CalculateMax.groovy

class CalculateMax{
    def Integer getMax(List values){
        values.max();
    }
}

UseGroovyClassLoader.java

package groovy_java_1;

import java.io.File;
import java.util.ArrayList;

import groovy.lang.GroovyClassLoader;
import groovy.lang.GroovyObject;

public class UseGroovyClassLoader {
    public static void main(String[] args){
        GroovyClassLoader loader = new GroovyClassLoader();
        try{
            Class<?> groovyClass = loader.parseClass(new File("src/groovy_java_1/CalculateMax.groovy"));
            GroovyObject groovyObject = (GroovyObject) groovyClass.newInstance(); 
            ArrayList<Integer> numbers = new ArrayList<Integer>();
            numbers.add(new Integer(1));
            numbers.add(new Integer(10));
            Object[] arguments = {numbers};
            Object value = groovyObject.invokeMethod("getMax", arguments);
            assert value.equals(new Integer(10));
            System.out.println(value);
        }catch(Exception e){
            e.printStackTrace();
        }
    }

}

二：在java中用GroovyShell执行groovy代码

UseGroovyShell.java

package groovy_java_0;

import java.math.BigDecimal;

import groovy.lang.Binding;
import groovy.lang.GroovyShell;

public class UseGroovyShell {
    public static void main(String[] args){
        Binding binding = new Binding();
        binding.setVariable("x", 2.4);
        binding.setVariable("y",8);
        GroovyShell shell = new GroovyShell(binding);
        Object value = shell.evaluate("x+y");
        assert value.equals(new BigDecimal(10.4));
    }

}

三：在java中用GroovyScriptEngine执行Groovy代码

Hello.groovy

def hellostatement = "hello ${name}"

UseGroovyScriptEngine.java

package groovy_java_2;

import groovy.lang.Binding;
import groovy.util.GroovyScriptEngine;

public class UseGroovyScriptEngine {
    public static void main(String[] args){
        try {
            String[] roots = new String[]{"src/groovy_java_2"};    //设置根目录
            GroovyScriptEngine gse = new GroovyScriptEngine(roots);    //初始化引擎
            
            Binding binding = new Binding();
            binding.setVariable("name", "Gweneth");
            
            Object output = gse.run("Hello.groovy", binding);
            System.out.println(output);
            assert output.equals("hello Gweneth");

        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
    }

}