java接口脚本咋写的,Java脚本教程：Java 脚本实现接口

在脚本中实现Java接口

Java Scripting API允许我们以脚本语言实现Java接口。

例子

假设我们想在Javascript中实现下面的Java接口。

public interface Calculator {

double add (double n1, double n2);

}

cal.js文件的内容，保存在c:/Java_dev/cal.js下

function add(n1, n2) {

n1 + n2;

}

从Java代码调用JavaScript中实现的Java接口。

import javax.script.Invocable;

import javax.script.ScriptEngine;

import javax.script.ScriptEngineManager;

import javax.script.ScriptException;

public class Main {

public static void main(String[] args) throws Exception {

ScriptEngineManager manager = new ScriptEngineManager();

ScriptEngine engine = manager.getEngineByName("JavaScript");

if (!(engine instanceof Invocable)) {

System.out.println("Interface implementation in script"

+ "is not supported.");

return;

}

Invocable inv = (Invocable) engine;

String scriptPath = "c:/Java_Dev/cal.js";

engine.eval("load("" + scriptPath + "")");

Calculator calc = inv.getInterface(Calculator.class);

if (calc == null) {

System.err.println("Calculator interface "

+ "implementation not found.");

return;

}

double x = 2.0;

double y = 1.0;

double addResult = calc.add(x, y);

System.out.println(addResult);

}

}