java - Check if number is too large or not a number -

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i trying parse string safely,

public <t> long safeparselong(t s){     try {         return long.parselong(s.tostring());     }catch (numberformatexception e){         return 0;     } }

this work , if string not parsable, return 0.

however, there way know reason unparsable? specifically, want know if not number @ ("foo") or number large (≥ 9223372036854775808).

the long.parselong method throw numberformatexception if string isn't number or if number wouldn't fit in long.

if exception thrown, test whether string fits regular expression number, "[+-]?[0-9]+". if matches, it's number couldn't fit in long. if doesn't match, wasn't number @ all, e.g. "foo".

boolean isnumber = s.tostring().matches("[+-]?[0-9]+");

but returning 0 if there error. indistinguishable if content of string "0". perhaps better let exception thrown method. instead of numberformatexception, create , throw notanumberexception if it's not numeric string, or numbermagnitudetoolargeexception if parsing failed because it's large fit in long.


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