求解：commons-jexl计算问题

[十线城市拆迁户]

package com.houlling.kftc.GeneralUtils;

import org.apache.commons.jexl2.Expression;
import org.apache.commons.jexl2.JexlContext;
import org.apache.commons.jexl2.JexlEngine;
import org.apache.commons.jexl2.MapContext;

import java.util.HashMap;
import java.util.Map;

/**
 * 公式计算
 */
public class CaculationUtils {

    public static Object caculation(String jexlExp, Map<String, Object> map){
        JexlEngine jexl = new JexlEngine();
        Expression expression = jexl.createExpression(jexlExp);
        JexlContext jc = new MapContext();
        for (String key : map.keySet()) {
            jc.set(key, map.get(key));
        }
        if (null == expression.evaluate(jc)) {
            return "";
        }
        Object o = expression.evaluate(jc);
        return expression.evaluate(jc);
    }


    /**
     * 调用方式
     */

    public static void test(){
        // 执行字符串表达式：(k-(x-y)*0.1)，进行计算
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("x", 1.002);
        map.put("y", 1.005);
        String formula = "(x+y)/2";
        Object result = caculation(formula,map);
        System.out.println(result);
    }

}

 

 

结果居然是：1.00349999.....，求解，谢谢