Whether the Java decision string can be converted to a number

In Java operations, it often involves converting string strings to int numbers.

which strings can be converted to numbers, which cannot, and cannot always be judged by whether Integer.parseint () throws an exception.

Just met the conversion situation, summed up the next, share it out.

Defining Method signatures

[Java] view plain copy/** * To see if a string can be converted to a number * @param str string * @return true; False can/* public static Boolean isstr2num (String str) {}
How do you implement the method body? Two different ways

Method 1 Integer.parseint Conversion

[Java] view plain copy try {integer.parseint (str);   return true;   catch (NumberFormatException e) {return false; }

Method 2 Regular Expression

[Java] view plain copy pattern = pattern.compile ("^[0-9]*$");   Matcher Matcher = Pattern.matcher (str); return matcher.matches ();

Integer also has a static method valueof (String s) to view the source

[Java] view plain copy public static Integer valueof (String s) throws NumberFormatException {return inte   Ger.valueof (parseint (S, 10)); }

valueof (string s) also first converts the string to a number by parseint () before converting it to an integer object.

and parseint (String s) returns an int variable, saving the overhead of heap memory

[Java] view plain copy public static int parseint (String s) throws NumberFormatException {return Parsein   T (s,10); }
So, here's the judgment to use parseint on it. --This article is from: Whether the Java Judge string can be converted to a number