java执行JavaScript代码

学习资料http://jnotnull.iteye.com/blog/262384

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

import sun.org.mozilla.javascript.internal.NativeArray;
import sun.org.mozilla.javascript.internal.NativeObject;

public class TestScript {
	public static void main(String[] args) throws Exception {
		ScriptEngineManager factory = new ScriptEngineManager();
		ScriptEngine engine = factory.getEngineByName("JavaScript");
		// engine.eval("print('hello')");
		// testScriptVariables(engine);// 演示如何暴露Java对象为脚本语言的全局变量
		// testInvokeScriptMethod(engine);// 演示如何在Java中调用脚本语言的方法
		// testScriptInterface(engine);// 演示脚本语言如何实现Java的接口
		// testUsingJDKClasses(engine);// 演示脚本语言如何使用JDK平台下的类

		test(engine);
	}

	public static void testScriptVariables(ScriptEngine engine)
			throws ScriptException {
		Map<String, Object> map = new HashMap<String, Object>();

		engine.put("map", map);
		engine.eval("map.put('s',new Date);");
		System.out.println(map.get("s").getClass());
	}

	public static void testInvokeScriptMethod(ScriptEngine engine)
			throws Exception {
		String script = "function hello(name) { return 'Hello,' + name;}";
		engine.eval(script);
		Invocable inv = (Invocable) engine;
		String res = (String) inv.invokeFunction("hello", "Scripting");
		System.out.println("res:" + res);
	}

	public static void testScriptInterface(ScriptEngine engine)
			throws ScriptException {
		String script = "var obj = new Object();obj.run = function() { println('run method called');}";
		engine.eval(script);
		Object obj = engine.get("obj");
		Invocable inv = (Invocable) engine;
		Runnable r = inv.getInterface(obj, Runnable.class);
		Thread th = new Thread(r);
		th.start();
	}

	public static void testUsingJDKClasses(ScriptEngine engine)
			throws Exception {
		// Packages是脚本语言里的一个全局变量,专用于访问JDK的package
		// String js = "function doSwing(t){var f=new
		// Packages.javax.swing.JFrame(t);f.setSize(400,300);f.setVisible(true);}";
		String js = "function doSwing(t){var f=Packages.java.util.UUID.randomUUID();print(f)}";
		engine.eval(js);
		Invocable inv = (Invocable) engine;
		inv.invokeFunction("doSwing", "Scripting Swing");
	}

	/**
	 * 我能想到的应用场景，将前台传过来的json数组构造成java的List<Map<String,
	 * Object>>,然后就可以随心所欲的使用该list了 当然可以使用第三方jar采用json to
	 * bean的方式，而且这种方案更优雅，但是需要引入第三方库
	 * 
	 * @throws NoSuchMethodException
	 * @throws ScriptException
	 */

	public static void test(ScriptEngine engine) throws ScriptException,
			NoSuchMethodException {

		// String json =
		// "{'key1':'a','son':{'dd':'dd','a':8},'ran':Math.random()},{'key3':'xor'}";
		String json = "{'key1':'a','son':[{'dd':'dd'},{'dd1':'dd1'}],'ran':Math.random()},{'key3':'xor'}";
		NativeArray json2array = json2array(engine, "[" + json + "]");
		List<Map<String, Object>> list = array2list(engine, json2array);
		System.out.println(list);

	}

	public static NativeArray json2array(ScriptEngine engine, String json)
			throws ScriptException, NoSuchMethodException {

		String script = "function hello() { return " + json + ";}";
		engine.eval(script);
		Invocable inv = (Invocable) engine;
		Object obj = inv.invokeFunction("hello");

		// System.out.println(obj);
		return (NativeArray) obj;

	}

	public static List<Map<String, Object>> array2list(ScriptEngine engine,
			NativeArray nativeArray) throws ScriptException,
			NoSuchMethodException {
		List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
		engine.put("list", list);
		engine.put("arr", nativeArray);
		String script = " 	function dosomething(){										"
				+ " 																			"
				+ " 					for (n=0; n< arr.length; n++){							"
				+ " 						var map=new Packages.java.util.HashMap();			"
				+ "							for (i in arr[n]){									"
				+ "								map.put(i,arr[n][i]);							"
				+ "							}													" + "							list.add(map);										"
				+ "						}														" + "					} 															";
		engine.eval(script);

		Invocable inv = (Invocable) engine;
		inv.invokeFunction("dosomething");
		for (Map<String, Object> map : list) {
			Set<Entry<String, Object>> entrySet = map.entrySet();
			for (Entry<String, Object> entry : entrySet) {
				Object object = entry.getValue();
				if (object instanceof NativeArray) {

					map.put(entry.getKey(), array2list(engine,
							(NativeArray) object));
				} else if (object instanceof NativeObject) {
					map.put(entry.getKey(), obj2map(engine,
							(NativeObject) object));
				}
			}

		}

		return list;

	}

	public static Map<String, Object> obj2map(ScriptEngine engine,
			Object nativeObject) throws ScriptException, NoSuchMethodException {
		Map<String, Object> map = new HashMap<String, Object>();

		engine.put("map", map);
		engine.put("obj", nativeObject);
		String script = " 	function dosomething(){											"
				+ "							for (i in obj){											"
				+ "								map.put(i,obj[i]);									"
				+ "							}														" + "					} 																";
		engine.eval(script);

		Invocable inv = (Invocable) engine;
		inv.invokeFunction("dosomething");
		return map;

	}

}

评论

1 楼 chen4w 2011-07-04  

我在java程序中调用javaScript引擎时，jdk内置脚本引擎不能将js 的map自动识别为java的map，最后采用您文章中的obj2map思路予以解决，谢谢！