public static boolean isDigit(String str, int beginIndex, int endIndex)
    {
        char c;
        for ( int j = beginIndex; j < endIndex; j++ ) {
            c = str.charAt(j);
            //make full-width char half-width
            if ( c > 65280 ) c -= 65248;
            if ( c < 48 || c > 57 ) {
                return false;
            }
        }

        return true;
    }
public static boolean isDigit ( String str , int beginIndex , int endIndex ) { char c ; for ( int j = beginIndex ; j < endIndex ; j ++ ) { c = str . charAt ( j ) ; if ( c > 65280 ) c -= 65248 ; if ( c < 48 || c > 57 ) { return false ; } } return true ; }
check the specified char is a digit or not
true will return if it is or return false this method can recognize full-with char

@param   str
@param   beginIndex
@param   endIndex
@return  boolean