JEP是java數學解析器的一個開源工具，解析并計算與數學運算相關的字符串的一個類庫，是java數學解析器的一個開源工具,提供第三方的jar包只要將jar包放到lib目錄下即可使用

簡單示例：

import com.singularsys.jep.Jep;
import com.singularsys.jep.JepException;

public class SimpleExample {
    public static void main(String[] args) {
        Jep jep = new Jep();
        //一個數學表達式
        String exp = "((a+b)*(c+b))/(c+a)/b";
        //給變量賦值
        jep.addVariable("a", 10);
        jep.addVariable("b", 10);
        jep.addVariable("c", 10);
 
       try {
           //執行
           jep.parse(exp);
           Object result = jep.evaluate();
           System.out.println("計算結果： " + result);
        } catch (JepException e) {
            System.out.println("An error occured: " + e.getMessage());
        }
    }
}

具體更復雜的操作可以參看下載的zip中\doc\html\index.html

Jep is a Java library for parsing and evaluating mathematical expressions. With this package you can allow your users to enter an arbitrary formula as a string, and instantly evaluate it. Jep supports user defined variables, constants, and functions. A number of common mathematical functions and constants are included.
參考資料：http://www.singularsys.com/jep/doc/html/index.html