In this example we shall show you how to access a Java Object from a script. We are using the ScriptEngine interface that provides methods for the basic scripting functionality. To access a Java Object from a script one should perform the following steps:
getEngineByExtension(String extension) API method to look up and create a ScriptEngine for the js extension.put(String key, Object value) API method of ScriptEngine to set a key/value pair in the state of the ScriptEngine that may either create a Java Language Binding to be used in the execution of scripts or be used in some other way, depending on whether the key is reserved. The value set here is a list of String car brands, with the key "brandArray".eval(String script) method to execute the script,as described in the code snippet below.
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 | package com.javacodegeeks.snippets.core;import javax.script.ScriptEngineManager;import javax.script.ScriptEngine;import javax.script.ScriptException; public class AccessJavaObjectFromScript { public static void main(String[] args) { // Create an array of car brands String[] brands = {"Audi", "Mercedes", "Renault", "Ford", "Seat"}; // Script that reads the values of the array that contains string of car brands. String script = "var index; " + "var brands = brandsArray; " + " " + "for (index in brands) { " + " println(brands[index]); " + "}" ; // Obtain a ScriptEngine instance. ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByExtension("js"); // Place the brands array into the engine using brandsArray key. engine.put("brandsArray", brands); try {engine.eval(script); } catch (ScriptException e) {e.printStackTrace(); } }} |
Output:
Audi
Mercedes
Renault
Ford
Seat
This was an example of how to access a Java Object from a script in Java.
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