NASHORN-JS engine

Nashorn is the operating environment for efficient and dynamic execution of JS code in Java.

New Scriptenginemanager (). Getenginebyname ("Nashorn");        Engine.eval (//  execute JS from source        new File ("Resources/scripts.js");        Engine.eval (new//  Execute JS from file

Call JS

First, save the JS code that needs to be called as Scripts.js:

function Add (A, b) {    return a + b;} var function (name) {    print ("JS:" + name);     return "Greeting from JS";} var function (obj) {    print ("JS Class:" + Object.prototype.toString.call (obj));}

Called in Java:

ScriptEngine engine =NewScriptenginemanager (). Getenginebyname ("Nashorn"); Engine.eval ("Print (' Hello ');");//Execute JS from sourceFile f =NewFile ("Resources/scripts.js"); Engine.eval (NewFileReader (f));//Execute JS from file        invocable invocable = (invocable) engine; Object sum=invocable.invokefunction("Add", 1, 2);        SYSTEM.OUT.PRINTLN (sum); Invocable.invokefunction ("F2",NewDate ()); Invocable.invokefunction ("F2", Localdatetime.now ());

Because the code in JS is the original ecological call in the JVM, the type is not lost.

Calling Java

The Java method must be public . Otherwise, it cannot be found at the time of the call :

     Public Static string Greeting (string name) {        System.out.println ("from Java" + name);         return "From Java";    }      Public Static void getcls (Object obj) {        System.out.println (Obj.getclass ());    }

ScriptEngine engine = new Scriptenginemanager (). Getenginebyname ("Nashorn");
File F = new file ("Resources/scripts.js");
Engine.eval (new FileReader (f)); Execute JS from File

JS Code:

var cls = Java.type ("Nashorn". Nashorntest ");p rint (cls.greeting (' Zhijie '));

The original JS type can be converted into the appropriate Java wrapper class. A native JS object is represented as an internal adaptation class.

　　

CLS.GETCLS (123);//class Java.lang.IntegerCls.getcls (49.99);//class Java.lang.DoubleCls.getcls (true);//class Java.lang.BooleanCls.getcls ("Hi There")//class Java.lang.StringCls.getcls (NewNumber (23));//class Jdk.nashorn.internal.objects.NativeNumberCls.getcls (NewDate ());//class Jdk.nashorn.internal.objects.NativeDateCls.getcls (NewRegExp ());//class Jdk.nashorn.internal.objects.NativeRegExpcls.getcls ({foo:' Bar '});//class Jdk.nashorn.internal.scripts.JO4

Scriptobjectmirror

Jdk.nashorn.api.scripting.ScriptObjectMirror is the mapping of JS objects in Java. This class implements the map interface.

 public  static  void   F ( scriptobjectmirror  Mirror) {System.out.println (mirr Or.  GetClassName  ()  + ":" + arrays.tostring (mirror.     Getownkeys  ( true   public  static  void   Callmethodofjsobject (scriptobjectmirror person) {System.out.println ( span> "Full Name was:" + person.  Callmember     ("Getfullname" 

CLS.F ({A: ' A ', B: ' B '}); function Person (FirstName, lastName) {    this. firstName = firstName;      this. lastName = lastName;      This function () {        returnthis. lastName;    }} var New Person ("Zhijie", "Liu"); Cls.callmethodofjsobject (Person1);

Nashorn expanded the ECMAScript 5:

• Typed Arrays

• Collections and for each

• Lambda Expressions and Streams

• Extending classes

• Parameter overloading

• Java Beans

• Function literals

• Binding Properties

• Trimming strings

• Whereis

• Import Scopes

• Convert arrays

• Calling Super

• Loading scripts

Can read further http://winterbe.com/posts/2014/04/05/java8-nashorn-tutorial/

NASHORN-JS engine