Java 乘以 Bigdecimal 和 int 生成错误
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multiply Bigdecimal and int generating error
提问by Siva
I have one value like 0.0004when I store this in Integerit is converting into Exponentialformat, So I have used Bigdecimalto convert it to normal value like below
我有一个值，就像0.0004我将Integer它存储在其中时正在转换为Exponential格式一样，所以我曾经Bigdecimal将其转换为正常值，如下所示
Bigdecimal x=BigDecimal.valueOf(0.0004)
Now I am trying to multiply as x*100but I am getting below error.
现在我正试图乘以x*100但我得到低于错误。
Error: The operator * is undefined for the argument type(s) BigDecimal, int
Because of this error if I use this without bigdecimal again it is converting to EXponential.
由于这个错误，如果我在没有 bigdecimal 的情况下再次使用它，它会转换为EXponential.
Can any one please suggest me the way to multiply Bigdecimal and int.
任何人都可以请给我建议乘法Bigdecimal and int。
googled a lot but couldn't find the correct solution.
谷歌搜索了很多，但找不到正确的解决方案。
Thanks for your time
谢谢你的时间
采纳答案by Mena
You can use BigDecimal.multiplyto multiply your BigDecimal.
您可以使用BigDecimal.multiply乘以您的BigDecimal.
However, the int value of 0.0004 * 100will be 0, which is probably not what you want.
但是，0.0004 * 100will的 int 值0可能不是您想要的。
Finally, you can alter the how the BigDecimalis represented in terms of fractional digits by using a NumberFormatinstance and formatting your Number.
最后，您可以BigDecimal通过使用NumberFormat实例并格式化您的Number.
Here's an example:
下面是一个例子：
BigDecimal x= BigDecimal.valueOf(0.0004);
BigDecimal y = x.multiply(new BigDecimal("100"));
int z = y.intValue();
System.out.printf("y is %s\tz is %d%n", y, z);
// edit to truncate fractional digits
NumberFormat nf = NumberFormat.getInstance();
nf.setMaximumFractionDigits(2);
System.out.printf("y (2 fraction digits) is %s", nf.format(y));
Output
输出
y is 0.04000 z is 0
y (2 fraction digits) is 0.04
回答by Anubian Noob
BigDecimal's are objects. They don't have normal operators.
BigDecimal是对象。他们没有普通的操作员。
Instead of a normal multiplication operator like x*10, you need to call the method multiplyin BigDecimal:
x*10您需要multiply在 BigDecimal 中调用该方法，而不是像 那样的普通乘法运算符：
x = x.multiply(new BigDecimal(10));
If you want to store it in a new value:
如果要将其存储在新值中：
BigDecimal n = x.multiply(new BigDecimal(10));
And to convert that to a primative:
并将其转换为原始：
double d = n.doubleValue();
int i = n.intValue();
However, if you're trying to use decimals, why not just use a double:
但是，如果您尝试使用小数，为什么不使用双精度数：
double x = 0.0004;
double n = x*100;
