java 脚本引擎执行javascript脚本

java脚本引擎是从JDK6.0之后添加的新功能，语法使用Rhino。

public class ScriptTest {
    public static void main(String args[]) throws ScriptException, NoSuchMethodException, IOException {
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("javascript");

        //声明一个msg 变量
        engine.put("msg","this is msg!");

        String jsCode = "var a = 10; var b =20;println(a+b);";
        //执行javascript代码
        engine.eval(jsCode);
        //修改变量
        engine.eval("msg = 'this is msg2!';println(msg);");
        //使用java获取变量
        System.err.println(engine.get("msg"));
        //执行js方法
        String jsFunc="function add(a,b){return a+b}";
        engine.eval(jsFunc);
        Invocable invocable = (Invocable) engine;
        Object res = invocable.invokeFunction("add",new Object[]{5,7});
        System.err.println(res);

        //在脚本中使用java
        String importJava = "importPackage(java.util);var list = Arrays.asList([\"嘻嘻\",\"哈哈\",\"咕咕\"]);";
        engine.eval(importJava);
        List list = (List) engine.get("list");
        System.err.println(list);

        //执行js文件
        URL url = ScriptTest.class.getClassLoader().getResource("test.js");
        FileReader reader = new FileReader(url.getPath());
        engine.eval(reader);
        reader.close();

    }

test.js(src下)

var a = 10;
var b = 30;
function mul() {
    return a*b;
}

println(mul());