Java详解ScriptEngine接口动态执行JS脚本

    /**
     * ScriptEngine.eval()
     */
    public void jsEngineEvalTest() {
        ScriptEngineManager sem = new ScriptEngineManager();
        //查找并为给定的扩展创建ScriptEngine。也可用getEngineByName，查找并为给定名称创建ScriptEngine 
        ScriptEngine jsEngine = sem.getEngineByExtension("js");
        try {
            jsEngine.eval("var array = [1, 2, 3, 4, 5];for (var i = 0; i < array.length; i++) {print('index:' + i + ',value:' + array[i]);}");
        } catch (ScriptException e) {
            e.printStackTrace();
        }
    }

    /**
     * ScriptEngine.put() and ScriptEngine.get()
     */
    public void jsEnginePutTest(){
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("javascript");
        //向engine中存值
        engine.put("str", "jsEnginePutTest");
        try {
            engine.eval("var output ='' ;for (i = 0; i <= str.length; i++) {  output = str.charAt(i) + output }");
        } catch (ScriptException e) {
            e.printStackTrace();
        }
        //从engine中取值
        String name = (String) engine.get("output");
        System.out.println("被翻转后的字符串:"+name);
    }

    /**
     * CompiledScript
     */
    public void compiledScriptTest(){
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("javascript");
        //进行强制转换
        Compilable compilable = (Compilable) engine;
        String script = "print('CompiledScriptTest')";
        try {
        	//脚本解析结果存到JSFunction中,下次使用时用jsFunction.eval()即可
            CompiledScript jsFunction = compilable.compile(script);
            jsFunction.eval();
        } catch (ScriptException e) {
            e.printStackTrace();
        }
    }

    /**
     * Bindings
     */
    public void jsEngineBindingsTest(){
        ScriptEngine engine = new ScriptEngineManager().getEngineByName("javascript");
        Compilable compilable = (Compilable) engine;
        Bindings bindings = engine.createBindings();
        String script = "function add(num1,num2){return num1+num2} add(a, b)";
        CompiledScript JSFunction = null;
        try {
            JSFunction = compilable.compile(script);
            //向bingdings中传入键值对
            bindings.put("a", 1);
            bindings.put("b", 2);
            //调用eval时将bindings也传入
            Object result = JSFunction.eval(bindings);
            System.out.println(result);
        } catch (ScriptException e) {
            e.printStackTrace();
        }
    }