java - 大值的 double 到 long 转换不会产生相同的值

Question

这个问题已经有答案了:

Why are floating point numbers inaccurate? (5 个回答)

已关闭 5 年前。

double d = 1000000000138719341D;
System.out.print(Double.valueOf(d).longValue());

打印结果为

1000000000138719360

为什么不一样？我怎样才能得到正确的结果？

Answer 1

来自docs :

double: The double data type is a double-precision 64-bit IEEE 754 floating point. Its range of values is beyond the scope of this discussion, but is specified in the Floating-Point Types, Formats, and Values section of the Java Language Specification. For decimal values, this data type is generally the default choice. As mentioned above, this data type should never be used for precise values, such as currency.