Java：将双精度转换为字符串

Question

I have a double whose value is 10,000,000.00 (ten millions). I have to convert it to a String . When using the method toString I am getting the String "1.0E7" which is correct following the specification. Unfortunately I need the String "10,000,000.00" (or the equivalent depending on the locale).

How can achieve this?

Answer 1

Try either

NumberFormat http://java.sun.com/javase/6/docs/api/java/text/NumberFormat.html

DecimalFormat http://java.sun.com/javase/6/docs/api/java/text/DecimalFormat.html

Answer 2

In addition to the formatter, you might consider using the java.math.BigDecimal class to represent numbers precisely.

Calculations where complete accuracy is required, such as financial calculations, are best performed with BigDecimal . Floating point math is better for engineering, graphics, and other mathematical computations where some accuracy can be sacrificed for speed.

Answer 3

  public static void main(String[] args) throws ParseException {
    double aDouble = 10000000.00;
    DecimalFormat nf = (DecimalFormat) NumberFormat.getInstance(Locale.US);
    String aString = Double.toString(aDouble);
    System.out.println(nf.parse(aString));
  }

Answer 4

Look into "DecimalFormat". It lets you format the output pretty much however you want!