本文参考自《会说话的代码》，本书值得一看

一个文本框中，只允许下列字符：0～9，a，b，e，：。那么对应的检验方法可能如下：

public static boolean isValidate1(char text) {
	String[] allowedChars = new String[] { "0","1","2","3","4","5","6","7","8","9","a","b","e",":" };

	for (String ac : allowedChars) {
		if (ac.charAt(0) == text) {
			return true;
		}
	}
	return false;
}

使用正则表达式：

public static boolean isValidate2(char text) {
	return String.valueOf(text).matches("[0~9abe:]");
}