【java】正则判断是否日期（年月日）字符串

/**
 * 日期分隔符，处理特殊字符
 *
 * @param splitter
 * @return
 */
private static String dealWithSplitter(char splitter) {
    String strSplitter = String.valueOf(splitter);
    String[] str = {".", "+", "*", "|", "?"};
    if (Arrays.asList(str).contains(strSplitter)) {
        strSplitter = "[" + strSplitter + "]";
    } else if ("^".equals(strSplitter)) {
        strSplitter = "\\^";
    } else if ("(".equals(strSplitter)) {
        strSplitter = "\\(";
    } else if (")".equals(strSplitter)) {
        strSplitter = "\\)";
    } else if ("{".equals(strSplitter)) {
        strSplitter = "\\{";
    } else if ("}".equals(strSplitter)) {
        strSplitter = "\\}";
    } else if ("[".equals(strSplitter)) {
        strSplitter = "\\[";
    } else if ("]".equals(strSplitter)) {
        strSplitter = "\\]";
    }
    return strSplitter;
}

/***
 * 判断字符串是否是yyyyMMdd、yyyyMdd、yyyyMMd、yyyyMd格式，分隔符为splitter参数
 * 例如：yyyy-MM-dd、yyyy.MM.dd
 *
 * @param mes
 * @param splitter
 * @return
 */
public static boolean isRqFormat(String mes, char splitter){
    if (null == mes || 0 == mes.length()) {
        return false;
    }
    String strSplitter = dealWithSplitter(splitter);
    // 1000年——2020
//        String format = "(1[0-9]{3}|20([0-1]{1}[0-9]{1}|20))" + strSplitter + "([1-9]|0[1-9]|1[012])" + strSplitter + "([1-9]|0[1-9]|[12][0-9]|3[01])";
    // 0000年——9999年
    String format = "([0-9]{4})" + strSplitter + "([1-9]|0[1-9]|1[012])" + strSplitter + "([1-9]|0[1-9]|[12][0-9]|3[01])";
    Pattern pattern = Pattern.compile(format);
    Matcher matcher = pattern.matcher(mes);
    if (!matcher.matches()) {
        return false;
    }
    pattern = Pattern.compile("(\\d{4})" + strSplitter + "(\\d{1,2})" + strSplitter + "(\\d{1,2})");
    matcher = pattern.matcher(mes);
    if (!matcher.matches()) {
        return false;
    }
    int y = Integer.valueOf(matcher.group(1));
    int m = Integer.valueOf(matcher.group(2));
    int d = Integer.valueOf(matcher.group(3));
    if (d > 28) {
        Calendar c = Calendar.getInstance();
        c.set(y, m-1, 1);
        int lastDay = c.getActualMaximum(Calendar.DAY_OF_MONTH);
        return lastDay >= d;
    }
    return true;
}

/***
 * 判断字符串是否是yyyyMMdd、yyyyMdd、yyyyMMd、yyyyMd格式
 *
 * @param mes
 * @return
 */
public static boolean isRqFormat(String mes){
    if (null == mes || 0 == mes.length()) {
        return false;
    }
    // 1000年——2020
//        String format = "(1[0-9]{3}|20([0-1]{1}[0-9]{1}|20))([1-9]|0[1-9]|1[012])([1-9]|0[1-9]|[12][0-9]|3[01])";
    // 0000年——9999年
    String format = "([0-9]{4})([1-9]|0[1-9]|1[012])([1-9]|0[1-9]|[12][0-9]|3[01])";
    Pattern pattern = Pattern.compile(format);
    Matcher matcher = pattern.matcher(mes);
    if (!matcher.matches()) {
        return false;
    }
    pattern = Pattern.compile("(\\d{4})(\\d{1,2})(\\d{1,2})");
    matcher = pattern.matcher(mes);
    if (!matcher.matches()) {
        return false;
    }
    int y = Integer.valueOf(matcher.group(1));
    int m = Integer.valueOf(matcher.group(2));
    int d = Integer.valueOf(matcher.group(3));
    if (d > 28) {
        Calendar c = Calendar.getInstance();
        c.set(y, m-1, 1);
        int lastDay = c.getActualMaximum(Calendar.DAY_OF_MONTH);
        return lastDay >= d;
    }
    return true;
}

参考文章：https://www.cnblogs.com/kiko2014551511/p/11547922.html