Call external javascript functions from java code

Question

By using Java Scripting API, I am able to execute JavaScript within Java. However, can someone please explain what I would need to add to this code in order to be able to call on functions that are in C:/Scripts/Jsfunctions.js

import javax.script.*;  public class InvokeScriptFunction { public static void main(String[] args) throws Exception {     ScriptEngineManager manager = new ScriptEngineManager();     ScriptEngine engine = manager.getEngineByName("JavaScript");      // JavaScript code in a String     String script1 = "function hello(name) {print ('Hello, ' + name);}";     String script2 = "function getValue(a,b) { if (a===\"Number\") return 1;                       else return b;}";     // evaluate script     engine.eval(script1);     engine.eval(script2);      Invocable inv = (Invocable) engine;      inv.invokeFunction("hello", "Scripting!!");  //This one works.        } } 

Answer 1

Use ScriptEngine.eval(java.io.Reader) to read the script

ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("JavaScript"); // read script file engine.eval(Files.newBufferedReader(Paths.get("C:/Scripts/Jsfunctions.js"), StandardCharsets.UTF_8));  Invocable inv = (Invocable) engine; // call function from script file inv.invokeFunction("yourFunction", "param");