JAVA执行字符串表达式 进行数值计算

package test;

import java.io.*;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
public class Test2
{
        public static void main(String[] args) throws Exception
        {
                String expr = "x+y*10";
                ScriptEngineManager manager = new ScriptEngineManager();
                ScriptEngine engine = manager.getEngineByName("js");
                engine.put("x", 10);
                engine.put("y", 10);
                Object result = engine.eval(expr);
               System.out.println(result);
        }
}