Java脚本引擎执行JavaScript代码

src下a.js

function test(){
    
    
    var arr = [1, 2, 3, 4, 7];

    for(i in arr){
    
    
        print(arr[i]);
    }
}

test();

import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import java.io.FileReader;
import java.net.URL;
import java.util.List;

/**
 * 测试脚本引擎执行JavaScript代码
 */
public class Demo01 {
    
    

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

        // 获得脚本引擎对象
        ScriptEngineManager sem = new ScriptEngineManager();
        ScriptEngine engine = sem.getEngineByName("javascript");

        // 定义变量, 存储到引擎上下文中
        engine.put("msg", "this is a string");
        String str = "var user = {name: 'xiaobo', age: 19};";
        str += "print(user.name);";

        // 执行脚本
        engine.eval(str);
        engine.eval("msg = 'Hello World'");

        System.out.println(engine.get("msg"));
        engine.eval("print(eval('9+3+4*5'))");

        // 定义函数
        engine.eval("function add(a, b){var sum = a + b; return sum;}");
        // 执行js代码
        // 1.
        Invocable jsInvoke = (Invocable)engine;
        Object result1 = jsInvoke.invokeFunction("add", new Object[]{
    
    13, 20});
        System.out.println(result1);
        // 2.
        engine.eval("for(var i=0;i<10;i++) print(add(1+i,3+i));");

        // 导入其他java包, 使用其他包中的java类
        String jsCode = "var list = java.util.Arrays.asList([\"java\",\"python\",\"c\"]);";
        engine.eval(jsCode);

        List list2 = (List<String>)engine.get("list");
        System.out.println(list2);
        // 执行js文件(src 下)
        URL url = Demo01.class.getClassLoader().getResource("a.js");
        FileReader fr = new FileReader(url.getPath());
        engine.eval(fr);
        fr.close();

    }
}