Java判断是否周末

import java.time.LocalDateTime;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
import java.time.ZoneId;

public class WeekendTest {

    public static void main(String[] args) throws Exception {
        Date cnDate = Date.from(LocalDateTime.now().atZone(TimeZone.getTimeZone("GMT+8").toZoneId()).toInstant());
        Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT+8"));  //不影响
        //Calendar calendar = Calendar.getInstance();  //不影响

        //calendar.setTime(cnDate);  //错误
        calendar.setTime(Date.from(LocalDateTime.now().atZone(ZoneId.systemDefault()).toInstant()));  //正确
        System.out.println(calendar.getTime());
        if (calendar.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY || calendar.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY) {
            System.out.println("WEEKEND");
        } else {
            System.out.println("NOT WEEKEND");
        }
    }

}