如何在Java中避免NumberFormatException？

Question

i searched, i found, but it all didn't work. my problem is that the NumberFormatException is thrown while I want to cast from String to double .

The string array atomized contains many strings and I tried to make an output before to make them visible so I could be sure there is data. the only problem is the double value. it is something like 5837848.3748980 but the valueOf method always throws the exception here. I have no idea why.

try
{
 int key = Integer.valueOf(atomized[0]);

 double value = Double.valueOf(atomized[1].trim());

 int role = Integer.valueOf(atomized[2]);

 Double newAccountState = this.bankKonto.charge(key, value, role);
 System.out.println("NEW Account State "+newAccountState);
 this.answerClient(newAccountState.toString());
}
catch (NumberFormatException e)
{
 System.out.println(e.getClass().toString()+" "+e.getMessage());
} 

Exception output:

java.lang.NumberFormatException: For input string: "109037.0"
        at java.lang.NumberFormatException.forInputString(Unknown Source)
        at java.lang.Integer.parseInt(Unknown Source)
        at java.lang.Integer.valueOf(Unknown Source)
        at vsys.ue02.server.Bank.computeData(Bank.java:122)
        at vsys.ue02.server.Bank.run(Bank.java:160)

Answer 1

It works fine here. So I'd assume your system locale has , rather than . for decimal separator. To avoid these things you can use DecimalFormat :

new DecimalFormat().parse("5837848.3748980");

Judging by the name of your variable - account - I assume you are dealing with money. You must never use floating point types to represent money. Use BigDecimal , or possibly int

Answer 2

This is a starting point for using DecimalFormat to convert strings to numbers. Also, if you are dealing with money and currencies, you should consider using BigDecimal instead of double.

Answer 3

您在一个带小数点的数字上使用Integer.parseInt - 这不是一个有效的整数 - 在堆栈跟踪中可见