如何在不使用尾数/指数格式的情况下打印浮点值？

Question

I am trying to print a double value. It is printing in matissa and exponent format, which is not what I want. For example, my program prints 1.234567E6 for the value 1243567. How can I make it print 1234657 ?

Answer 1

BigDecimal.valueOf(double).toPlainString();

Answer 2

您可能会研究NumberFormat类和DecimalFormat 。

Answer 3

I have been struggling with exactly the same problem, and the two answers here provide a clue on how to solve the problem: use a formatter. Neither answer explains precisely what parameters are needed to format a Double value, and avoid exponential notation.

There are two options. These are described in the documentation as "d" for decimal integer and "f" for decimal number. What I actually need is "fixed point" format, and that is not clearly described by the documentation, however f will give you fixed point if you set the parameters correctly. It will also give you an integer display if you set decimal points to zero.

For a Double value 12345678 formatting gives you the following results:

Double d = Double.parseDouble("12345678");
String r1 = String.format("%f",d);        // 12345678.000000
String r2 = String.format("%10f",d);      // 12345678.000000
String r3 = String.format("%5.2f",d);     // 12345678.00
String r4 = String.format("%5.0f",d);     // 12345678
String r5 = String.format("%,f",d);       // 12,345,678.000000
String r6 = String.format("%,5.0f",d);    // 12,345,678
String r7 = String.format("%d",d);        // throws an exception!

On the last one, even though you want an integer display of the number, you can not use the 'd' option with a Double.

Answer 4

检查一下： http : //java.sun.com/docs/books/tutorial/i18n/format/decimalFormat.html