Running JS__JS in Java programs

Jdk

1.6 version of the added ScriptEngine can run the JS code directly

1. Write JS code directly

Import Javax.script.ScriptEngine;

Import Javax.script.ScriptEngineManager;

Import javax.script.ScriptException; /**  * Directly call the JS code * *  

public class Scriptenginetest {

public static void Main (string[] args) {

  Scriptenginemanager manager = new Scriptenginemanager ();

  ScriptEngine engine = Manager.getenginebyname ("javascript");

     try{    

          engine.eval ("var a=3; var b=4;print (a+b); ");

         Engine.eval ("alert (\" JS alert\); ");    Unable to invoke the JS function//Error defined in the browser, throws an alert reference to an exception that does not exist

}catch (scriptexception e) {

 e.printstacktrace ();
 }
 } 
}

2. Call function

Import Java.io.FileReader; 
Import javax.script.Invocable;

 Import Javax.script.ScriptEngine;

 Import Javax.script.ScriptEngineManager;  
 /**  * java invoke and execute JS file, pass parameter, and activity return value  *   * @author Manjushri/public 

class Scriptenginetest { Public  

static void Main (string[] args) throws Exception {   
Scriptenginemanager manager = new Scriptenginemanager ();   
ScriptEngine engine = Manager.getenginebyname ("javascript");   

String jsfilename = "Expression.js";   Read JS file   

filereader reader = new FileReader (jsfilename);   Executes the specified script   
engine.eval (reader);   

if (engine instanceof invocable) {    
invocable invoke = (invocable) engine;    Call the merge method and pass in two parameters    

//c = Merge (2, 3);    

Double c = (double) invoke.invokefunction ("merge", 2, 3);    

System.out.println ("c =" + C);   
}   

Reader.close ();  

  }

JS file

Expression.js

function merge (A, b) {

c = A * b;

return C;

}