Ken Dad's Stringutils.isnumeric (String str)

A bug was encountered in the project and the result of debugging was Stringutils.isnumeric (String str) In the tricks (using org.apache.commons.lang.StringUtils), the following code is to determine that a parameter is non-null and is an integer:

if (Stringutils.isnumeric (str) && Stringutils.isnotblank (str)) {            // do sth}

In the simple code, but hide the bug!

because if str = "-1"; Stringutils.isnumeric (str) returns the false! It's not a good father.

Here is the test:

 Public Static void Main (string[] args) {        System.out.println (stringutils.isnumeric ("-1"));}

Run Result: false

Ken-dad, huh? Isn't it easy to implement regular expressions? How can this, read the following source:

 Public Static Booleanisnumeric (String str) {if(str = =NULL) {            return false; }        intSZ =str.length ();  for(inti = 0; I < sz; i++) {            if(Character.isdigit (Str.charat (i)) = =false) {                return false; }        }        return true; }

Continue to jump in:

 Public Static boolean isdigit (char  ch) {        return isdigit ((int) ch );}

Go on:

 Public Static BooleanIsDigit (intcodepoint) {        BooleanBdigit =false; if(codepoint >= min_code_point && codepoint <=Fast_path_max) {Bdigit=Characterdatalatin1.isdigit (codepoint); } Else {            intPlane =Getplane (codepoint); Switch(plane) { Case(0): Bdigit=Characterdata00.isdigit (codepoint);  Break;  Case(1): Bdigit=Characterdata01.isdigit (codepoint);  Break;  Case(2): Bdigit=Characterdata02.isdigit (codepoint);  Break;  Case(3)://Undefined             Case(4)://Undefined             Case(5)://Undefined             Case(6)://Undefined             Case(7)://Undefined             Case(8)://Undefined             Case(9)://Undefined             Case(10)://Undefined             Case(11)://Undefined             Case(12)://Undefined             Case(13)://UndefinedBdigit =Characterdataundefined.isdigit (codepoint);  Break;  Case(14): Bdigit=Characterdata0e.isdigit (codepoint);  Break;  Case(15)://Private Use             Case(16)://Private UseBdigit =Characterdataprivateuse.isdigit (codepoint);  Break; default:                //The argument ' s plane is invalid, and thus are an invalid codepoint//Bdigit remains false;                 Break; }        }        returnBdigit; }

Failure in the following step:

Static boolean isdigit (int  ch) {        int type = getType (CH);         return (Type = = character.decimal_digit_number);    }

In other words, his implementation completely did not take into account the-+ prefix problem, this is not a silly fork?

The following results are false:

 Public Static void Main (string[] args) {        System.out.println (stringutils.isnumeric ("-1"));        System.out.println (Stringutils.isnumeric ("+1"));

This is his way of commenting:

ChecksifThe String contains only Unicode digits. A decimal point was not a Unicode digit and returnsfalse.NULLWouldreturn false. An empty String ("") wouldreturn true. Stringutils.isnumeric (NULL)   =falseStringutils.isnumeric ("")     =trueStringutils.isnumeric ("  ")   =falseStringutils.isnumeric ("123") =trueStringutils.isnumeric ("12 3") =falseStringutils.isnumeric ("AB2C") =falseStringutils.isnumeric ("12-3") =falseStringutils.isnumeric ("12.3") =falseparameters:str the String to checkNULLReturns:true ifonly contains digits, and is non-NULL

Can only contain Unicode numbers, +,-,. None of the three can be counted as Unicode numbers.

Ken Dad's Stringutils.isnumeric (String str)