java8 新特性 v8 nashorn 引擎（五）

野性酷女 2022-08-07 07:47 17阅读 0赞

**简单的javascript 作为文本输出**

ScriptEngineManager manager = new ScriptEngineManager();  
        ScriptEngine engine = manager.getEngineByName("nashorn");  
  
        String js;  
  
        js = "var map = Array.prototype.map \\n";  
        js += "var names = \[\\"john\\", \\"jerry\\", \\"bob\\"\]\\n";  
        js += "var a = map.call(names, function(name) \{ return name.length() \})\\n";  
        js += "print(a)";  
  
        try \{  
            engine.eval(js);  
        \} catch (ScriptException e) \{  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        \}  
        ScriptEngine jse = new ScriptEngineManager().getEngineByName("nashorn");  
        try \{  
            jse.eval("print('Hello DoubleCloud! - inline');");  
        \} catch (ScriptException e) \{  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        \}

**执行javascript 文件**

ScriptEngineManager scriptEngineManager = new ScriptEngineManager();  
        ScriptEngine jse = scriptEngineManager.getEngineByName("nashorn");  
        System.out.println("current dir: " + new File(".").getAbsoluteFile());  
        try \{  
            jse.eval(new FileReader("./src/com/test/zcw/java/script.js"));  
        \} catch (FileNotFoundException e) \{  
            e.printStackTrace();  
        \} catch (ScriptException e) \{  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        \}

js文件语句：eval("print('Hello DoubleCloud! - inline');")

**调用javascript 函数**

ScriptEngineManager scriptEngineManager = new ScriptEngineManager();  
          ScriptEngine jse = scriptEngineManager.getEngineByName("nashorn");  
          
          jse.eval(new FileReader("./src/com/test/zcw/java/script.js"));  
          
          Invocable runner = (Invocable) jse;  
          
          Object result = runner.invokeFunction("hi", "DoubleCloud! - via javascript function");  
          System.out.println(result);  
          System.out.println(result.getClass());

函数内容：

var hi = function(name)  
\{  
  return 'Hi ' + name;  
\}

**javascript调用java**

var hw = Java.type('com.test.zcw.java8.JSNashorn');  
  
var result = hw.sayHi("DoubleCloud - calling Java method in JS.");  
print(result);

java

static public String sayHi(String name) \{  
        return "Hi " + name;  
    \}