原价是18元,优惠17.99元,保存的最终价格是0.02元。看了一下代码:
discount = (long) (Double.parseDouble(dis)*100); freight = (long) (Double.parseDouble(fre)*100);
用这段代码做了测试就发现问题所在了。是精度问题,然后强制long转换后,把小数后面的内容给丢了。
public static void main(String[] args) { //System.out.println((long) Math.round((Double.parseDouble("17.99")*100))); System.out.println((Double.parseDouble("17.99")*100)); System.out.println((long) (Double.parseDouble("17.99")*100)); System.out.println((Double.parseDouble("10.99")*100)); System.out.println((long) (Double.parseDouble("10.99")*100)); System.out.println((Double.parseDouble("8.99")*100)); System.out.println((long) (Double.parseDouble("8.99")*100)); }
输出结果:
1798.9999999999998 1798 1099.0 1099 899.0 899
最简单的解决方案,在long强制转化前四舍五入,代码如下
System.out.println((long) Math.round((Double.parseDouble("17.99")*100)));
更优化的写法当然是用bigDecimal,上面只是最偷懒的修改方式。