在法国的机器上执行时java.lang.NumberFormatException

Question

In below code while parsing the value sometimes i am facing NumberFormat Exception in France machine.

double txPower;
DecimalFormat df = new DecimalFormat("##.##");

txPower = txPower + getDeltaP();
log.info("txpower value is -- "+txPower);
txPower = Double.parseDouble(df.format(txPower));


protected double getDeltaP() 
{
    return isNewChannelAddition ? apaConfig.deltaPadd : apaConfig.deltaPtune;
}

logs:

txpower value is -- -7.9
java.lang.NumberFormatException: For input string: "-7,9"

Answer 1

我建议对您的语言环境使用配置为默认值的十进制分隔符。

new DecimalFormatSymbols(Locale.getDefault(Locale.Category.FORMA‌​T)).getDecimalSepara‌​tor();

Answer 2

You have to ways to solve your problem :

One, you can use replace(",", ".") like this :

txPower = Double.parseDouble(df.format(txPower).replace(",", "."));

Two, you can use the local for the DecimalFormat :

DecimalFormat df = (DecimalFormat) DecimalFormat.getInstance();
df.applyLocalizedPattern("##.##");
txPower = txPower + getDeltaP();
txPower = Double.parseDouble(df.format(txPower));

Answer 3

您也可以调用类似String.format("%.2f", -7.9)

Answer 4

Double.parseDouble doesn't support locale-specific decimal points (see the doc here ). Try using your DecimalFormat to parse instead:

txPower = df.parse(df.format(txPower)).doubleValue();

Having said that, I must ask what you are hoping to gain by to turning the double value txPower into a String , parsing the string into a double and putting the result back into txPower ?