正则表达式 查找字符串中的日期

String reg = "[1-9]\\d{3}(((0[13578]|1[02])([0-2]\\d|3[01]))|((0[469]|11)([0-2]\\d|30))|(02([01]\\d|2[0-8])))";
String str = "C120191030216410";
Pattern pattern = Pattern.compile (reg);
Matcher matcher = pattern.matcher (str);
while (matcher.find ())
{
    System.out.println (matcher.group ());
}