
简易控制台 计算器 代码
package com.yangyang.Test;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import java.util.Scanner;
public class Demo {
public static void main(String[] args) {
System.out.println("输入表达式: 格式 1+1 or 1+1=");
String calc = new Scanner(System.in).next();
int lastIdnex = calc.indexOf("=");
calc = calc.substring(0,lastIdnex<0?calc.length():lastIdnex);
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engin = manager.getEngineByName("javascript");
while (true){
try {
System.out.println(calc+"="+engin.eval(calc));
calc = new Scanner(System.in).next();
} catch (Exception e) {
System.out.println("输入不合法!请重新输入!");
calc = new Scanner(System.in).next();
}finally {
calc = calc.substring(0,lastIdnex<0?calc.length():lastIdnex);
}
}
}
}