在工作期間，將寫內容過程經常用到的一些內容段做個記錄，下面內容是關於Java判斷一個字元是否是數字的幾種方法的內容，希望能對碼農們有好處。

public class Test
{
public static void main(String[] args)
{
char[] ch =
{
'a', '1', 'b', '2', 'c', '3', 'd', '4',
};
System.out.println(ch[0] + ": " + isDigitA(ch[0]));
System.out.println(ch[1] + ": " + isDigitA(ch[1]));
System.out.println(ch[2] + ": " + isDigitB(ch[2]));
System.out.println(ch[3] + ": " + isDigitB(ch[3]));
System.out.println(ch[4] + ": " + isDigitC(ch[4]));
System.out.println(ch[5] + ": " + isDigitC(ch[5]));
System.out.println(ch[6] + ": " + isDigitD(ch[6]));
System.out.println(ch[7] + ": " + isDigitD(ch[7]));
}

private static boolean isDigitA(char ch)
{
return Character.isDigit(ch);
}

private static boolean isDigitB(char ch)
{
Pattern pattern = Pattern.compile("[0-9]");
return pattern.matcher(String.valueOf(ch)).matches();
}

private static boolean isDigitC(char ch)
{
if (ch < 48 || ch > 57)
return false;
else
return true;
}

private static boolean isDigitD(char ch)
{
try
{
int i = Integer.parseInt(String.valueOf(ch));
return true;
}
catch (NumberFormatException e)
{
e.printStackTrace();
return false;
}

}
}