利用JavaScript来执行运算

import java.util.*;
import javax.script.*;

public class Main {
    public static void main(String[] args) throws ScriptException {
        Scanner scan = new Scanner(System.in);
        String input = scan.nextLine();
        input = input.replace("[", "(");
        input = input.replace("]", ")");
        input = input.replace("{", "(");
        input = input.replace("}", ")");
        // 获取脚本引擎管理器
        ScriptEngineManager manager = new ScriptEngineManager();
        // 获取Script脚本引擎
        ScriptEngine engine = manager.getEngineByName("JavaScript");
        System.out.println(engine.eval(input));

    }


}