Java determines whether a character is in date format

java determines whether the character is in date format

determines whether the string is like "2018-02-30" Is the date a correct and reasonable date?

1. Use the format method of SimpleDateFormat to parse the string. If an error is reported, it is not a date format;

2. Use the split method to split the string into "-" is divided into an array;

3. Traverse the array and determine whether each element is a number. If not, the string is not in date format;

//假设传入的日期格式是yyyy-MM-dd HH:mm:ss, 也可以传入yyyy-MM-dd，如2018-1-1或者2018-01-01格式
public static boolean isValidDate(String strDate) {
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    try {
        // 设置lenient为false. 否则SimpleDateFormat会比较宽松地验证日期，比如2018-02-29会被接受，并转换成2018-03-01 
        
        format.setLenient(false);
        Date date = format.parse(strDate);
        
        //判断传入的yyyy年-MM月-dd日 字符串是否为数字
        String[] sArray = strDate.split("-");
        for (String s : sArray) {
            boolean isNum = s.matches("[0-9]+");
            //+表示1个或多个（如"3"或"225"），*表示0个或多个（[0-9]*）（如""或"1"或"22"），?表示0个或1个([0-9]?)(如""或"7")
            if (!isNum) {
                return false;
            }
        }
    } catch (Exception e) {
        // e.printStackTrace();
        // 如果throw java.text.ParseException或者NullPointerException，就说明格式不对
        return false;
    }

    return true;
}

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