Python将当前时间格式化为字符串:

    import datetime
    nowtime = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    

Java将当前时间格式化为字符串:

    import java.text.SimpleDateFormat;
    import java.util.Calendar;
    public class DateTimeTest {
        public static void main(String[] args) {
            Calendar calendar = Calendar.getInstance();
            calendar.add(Calendar.DATE,-1); //昨天
            SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            String formatedDate = simpleDateFormat.format(calendar.getTime());
            System.out.println(formatedDate);
        }
    }