DateTimeFormatter类

public class TimeTest {
    public static void main(String[] args) {
        //将字符串解析为时间类
        String strDate = "2020-03-15 13:11:20";
        DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        LocalDateTime localDateTime = LocalDateTime.parse(strDate,dateTimeFormatter);
        System.out.println(localDateTime);//输出2020-03-15T13:11:20

        //将时间类格式化输出
        LocalDateTime localDateTime1 = LocalDateTime.now();
        String str = localDateTime1.format(dateTimeFormatter);
        System.out.println(str); //输出2020-03-15 13:14:47
    }
}