Convert a String to Double - Java

Question

What is the easiest and correct way to convert a String number with commas (for example: 835,111.2) to a Double instance.

Thanks.

Answer 1

Have a look at java.text.NumberFormat. For example:

import java.text.*;
import java.util.*;

public class Test
{
    // Just for the sake of a simple test program!
    public static void main(String[] args) throws Exception
    {
        NumberFormat format = NumberFormat.getInstance(Locale.US);

        Number number = format.parse("835,111.2");
        System.out.println(number); // or use number.doubleValue()
    }
}

Depending on what kind of quantity you're using though, you might want to parse to a BigDecimal instead. The easiest way of doing that is probably:

BigDecimal value = new BigDecimal(str.replace(",", ""));

or use a DecimalFormat with setParseBigDecimal(true):

DecimalFormat format = (DecimalFormat) NumberFormat.getInstance(Locale.US);
format.setParseBigDecimal(true);
BigDecimal number = (BigDecimal) format.parse("835,111.2");