package chengyujia; import java.util.regex.Pattern; public class NumberUtil { /** * 判斷一個字符串是否是數字。 * * @param string * @return */ public static boolean isNumber(String string) { if (string == null) return false; Pattern pattern = Pattern.compile("^-?\\d+(\\.\\d+)?$"); return pattern.matcher(string).matches(); } private static void isNumberTest() { System.out.println(isNumber("123")); System.out.println(isNumber("-123.456")); System.out.println(isNumber("123成宇佳456")); } public static void main(String[] args) { isNumberTest(); } }
運行測試,控制檯輸出:
true
true
false