How to call js method in java

function add(a,b){
	return a + b + number;	
}

package com.cgnb.dataqualitymng;
 
import java.io.FileReader;
import java.util.Scanner;
 
import javax.script.Bindings;
import javax.script.Invocable;
import javax.script.ScriptContext;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
 
public class ExecuJs {
	public static void main(String[] args) throws Exception {
 
		// 获取JS执行引擎
		ScriptEngine se = new ScriptEngineManager().getEngineByName("javascript");
		// 获取变量
		Bindings bindings = se.createBindings();
		bindings.put("number", 3);
		se.setBindings(bindings, ScriptContext.ENGINE_SCOPE);
		Scanner sc = new Scanner(System.in);
		while (sc.hasNextInt()) {
			int a = sc.nextInt();
			int b = sc.nextInt();
			System.out.println("输入的参数【" + a + "】 + 【" + b + "】");
			se.eval(new FileReader("D:\\desk\\test.js"));
			// 是否可调用
			if (se instanceof Invocable) {
				Invocable in = (Invocable) se;
				Integer result = (Integer) in.invokeFunction("add", a, b);
				System.out.println("获得的结果：" + result);
				
			}
 
		}
 
	}
}