Java:为什么在现实世界中我们应该使用 BigDecimal 而不是 Double?
在处理现实世界的货币值时，建议我使用 BigDecimal 而不是 Double.但我没有得到令人信服的解释，除了通常这样做".
When dealing with real world monetary values, I am advised to use BigDecimal instead of Double.But I have not got a convincing explanation except, "It is normally done that way".
你能解释一下这个问题吗?
Can you please throw light on this question?
推荐答案
这称为精度损失，在处理非常大或非常小的数字时非常明显.带基数的十进制数的二进制表示在许多情况下是近似值而不是绝对值.要了解为什么您需要阅读二进制中的浮点数表示.这是一个链接:http://en.wikipedia.org/wiki/IEEE_754-2008.这是一个快速演示:
在精度=10 的 bc(任意精度计算器语言)中:
It's called loss of precision and is very noticeable when working with either very big numbers or very small numbers. The binary representation of decimal numbers with a radix is in many cases an approximation and not an absolute value. To understand why you need to read up on floating number representation in binary. Here is a link: http://en.wikipedia.org/wiki/IEEE_754-2008. Here is a quick demonstration:
in bc (An arbitrary precision calculator language) with precision=10:
(1/3+1/12+1/8+1/15) = 0.6083333332
(1/3+1/12+1/8) = 0.541666666666666
(1/3+1/12) = 0.416666666666666
(1/3+1/12+1/8+1/15) = 0.6083333332
(1/3+1/12+1/8) = 0.541666666666666
(1/3+1/12) = 0.416666666666666
Java 双重:
0.6083333333333333
0.5416666666666666
0.41666666666666663
Java double:
0.6083333333333333
0.5416666666666666
0.41666666666666663
Java 浮点数:
Java float:
0.60833335
0.5416667
0.4166667
0.60833335
0.5416667
0.4166667
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