/* 1.用JAVA自带的函数 */ |
private static boolean isDigitA ( char ch) { |
return Character.isDigit (ch); |
} |
/* 2.用正则表达式 */ |
private static boolean isDigitB ( char ch) { |
Pattern pattern = Pattern.compile ( "[0-9]" ); |
return pattern.matcher (String.valueOf (ch) ).matches(); |
} |
/* 3.用ascii码 */ |
private static boolean isDigitC ( char ch) { |
if (ch < 48 || ch > 57 ) { |
return false ; |
} else { |
return true ; |
} |
} |
/* 4.强制类型转化是否抛出异常来判断 */ |
private static boolean isDigitD ( char ch) { |
try { |
int i = Integer.parseInt (String.valueOf (ch) ); |
return true ; |
} catch (NumberFormatException e) { |
e.printStackTrace(); |
return false ; |
} |
} |