正则表达式 练习：验证是否整数或小数

https://www.bilibili.com/video/BV1Eq4y1E79W?p=25

要考虑正数和负数，比如：123、-345、34.89、-87.9、-0.01、0.45等

我的实现

public class Homework02 {

    public static void main(String[] args) {

        String regex = "^-?\\d+\\.?\\d*$";

        String[] contents = {"123", "-345", "34.89", "-87.9", "-0.01", "0.45", "--123", "-0.123", "abc"};

        for (String content:contents) {
            System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
        }

    }

}

"123".matches(regex):true 
"-345".matches(regex):true 
"34.89".matches(regex):true 
"-87.9".matches(regex):true 
"-0.01".matches(regex):true 
"0.45".matches(regex):true 
"--123".matches(regex):false 
"-0.123".matches(regex):true 
"abc".matches(regex):false

视频里的实现

public class Homework02 {

    public static void main(String[] args) {

        String regex = "^[-+]?(0|[1-9]\\d*)(\\.\\d+)?$";

        String[] contents = {"123", "-345", "34.89", "-87.9", "-0.01", "0.45", "--123", "-0.123", "abc", "0.89", "01.89"};

        for (String content:contents) {
            System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
        }

    }

}

"123".matches(regex):true 
"-345".matches(regex):true 
"34.89".matches(regex):true 
"-87.9".matches(regex):true 
"-0.01".matches(regex):true 
"0.45".matches(regex):true 
"--123".matches(regex):false 
"-0.123".matches(regex):true 
"abc".matches(regex):false 
"0.89".matches(regex):true 
"01.89".matches(regex):false