Parse a negative prefix integer from string in java

问题

Hi i have a string looking something like this 10 -1 30 -2 and i want to read the numbers between spaces. I can do this using a FOR statement and the code

Character.toString(myString.charAt(i));

and

Integer.parseInt(myString);

But i face a problem when i try to read negative number like -1 and i got the error message:

09-09 13:06:49.630: ERROR/AndroidRuntime(3365): Caused by: java.lang.NumberFormatException: unable to parse '-' as integer

Any ideas how to solve this ??

回答1:

You're trying to parse a single character ('-') (after converting it to a string, admittedly) instead of the string "-1". If you use charAt you'll be parsing a single digit at a time, so "10" will come out as 1 and then 0, not 10.

If you just split your string on spaces, you should be able to parse the strings with no problems.

回答2:

Is this what you want?

for (String number : "10 -1 30 -2".split("\\s"))
{
    int x = Integer.parseInt(number);
    System.out.println(x);
}

This will print:

10
-1
30
-2

回答3:

Maybe you want to use a StringTokenizer to split the String at certain characters.

StringTokenizer st = new StringTokenizer("10 -1 30 -2");
while (st.hasMoreTokens()) {
  String intStr = st.nextToken();
  int x = Integer.parseInt(intStr);
  System.out.println(x);
}

来源：https://stackoverflow.com/questions/7360111/parse-a-negative-prefix-integer-from-string-in-java