java如何判断星期
判断星期的方法
在Java中,可以使用java.util.Calendar或java.time包(Java 8及以上版本)来判断当前或指定日期是星期几。

使用java.util.Calendar
import java.util.Calendar;
public class WeekdayExample {
public static void main(String[] args) {
Calendar calendar = Calendar.getInstance();
int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
switch (dayOfWeek) {
case Calendar.SUNDAY:
System.out.println("今天是星期日");
break;
case Calendar.MONDAY:
System.out.println("今天是星期一");
break;
case Calendar.TUESDAY:
System.out.println("今天是星期二");
break;
case Calendar.WEDNESDAY:
System.out.println("今天是星期三");
break;
case Calendar.THURSDAY:
System.out.println("今天是星期四");
break;
case Calendar.FRIDAY:
System.out.println("今天是星期五");
break;
case Calendar.SATURDAY:
System.out.println("今天是星期六");
break;
}
}
}
使用java.time.LocalDate(Java 8及以上)
import java.time.LocalDate;
import java.time.DayOfWeek;
public class WeekdayExample {
public static void main(String[] args) {
LocalDate today = LocalDate.now();
DayOfWeek dayOfWeek = today.getDayOfWeek();
System.out.println("今天是" + dayOfWeek.toString());
}
}
自定义日期判断星期
如果需要判断指定日期的星期几,可以使用以下方法:

import java.time.LocalDate;
import java.time.DayOfWeek;
public class WeekdayExample {
public static void main(String[] args) {
LocalDate specificDate = LocalDate.of(2023, 10, 1);
DayOfWeek dayOfWeek = specificDate.getDayOfWeek();
System.out.println("指定日期是" + dayOfWeek.toString());
}
}
输出星期几的中文名称
如果需要输出中文星期名称,可以结合数组或switch语句:
import java.time.LocalDate;
import java.time.DayOfWeek;
public class WeekdayExample {
public static void main(String[] args) {
LocalDate today = LocalDate.now();
DayOfWeek dayOfWeek = today.getDayOfWeek();
String[] weekdays = {"星期一", "星期二", "星期三", "星期四", "星期五", "星期六", "星期日"};
System.out.println("今天是" + weekdays[dayOfWeek.getValue() - 1]);
}
}
以上方法可以根据需求选择使用,java.time包更推荐用于新项目。






