Using JavaScript in Java

Using JavaScript scripts in Java applications gives us more flexibility and extensibility. By interacting with JavaScript, we can execute JavaScript functions, pass parameters and receive return values, and call methods provided by Java objects. This article will explain how to use JavaScript in Java, combined with actual code examples.

Executing JavaScript functions in Java

To execute JavaScript function in Java, we can use the script engine provided by Java to achieve it. Java 8 introduces the javax.script package, which contains related classes and interfaces for interacting with scripts. Here is an example code:

import javax.script.*;

public class JavaScriptExecutor {
    public static void main(String[] args) throws ScriptException {
        // Create Script Engine
        ScriptEngineManager engineManager = new ScriptEngineManager();
        ScriptEngine engine = engineManager.getEngineByName("javascript");

        // Define JavaScript functions
        String script = "function add(a, b) { return a + b; }";

        // Execute JavaScript functions
        engine.eval(script);

        // Calling JavaScript functions and passing parameters
        Invocable invocable = (Invocable) engine;
        double result = (double) invocable.invokeFunction("add", 3, 4);
        System.out.println("Result: " + result);
    }
}