Java 中计算字符串表达式的值

Posted 2022-12-14 普通网友

Java 中计算字符串表达式的值

在 Java 中计算字符串数值表达式可以用 javax.script.ScriptEngine#eval(java.lang.String)，通过调用 javascript 来计算

import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class ExpressionCalculate 
    public static void main(String[] args) 
        ScriptEngineManager scriptEngineManager = new ScriptEngineManager();
        ScriptEngine scriptEngine = scriptEngineManager.getEngineByName("nashorn");
        String expression = "10 * 2 + 6 / (3 - 1)";

        try 
            String result = String.valueOf(scriptEngine.eval(expression));
            System.out.println(result);
         catch (ScriptException e) 
            e.printStackTrace();
        
    

结果： 23