Java DayOfWeek plus()方法及示例

java.time.DayOfWeek 的 plus() 方法是Java中的一个内置函数，它接收一个长整数作为参数，并按照所传递的参数指定的时间向前或向后推进一些日子后，返回DayOfWeek的一个实例。该计算围绕周末从周日到周一进行滚动。指定的周期可以是正数或负数。

方法声明 。

public DayOfWeek plus(long days)

语法

DayOfWeek dayOfWeekObject = dayOfWeekObject.plus(long days)

参数： 该方法将天数作为参数，其中。

• days – 是要向前或向后推进的天数。
• dayOfWeekObject – 是DayOfWeek对象的一个实例。

返回值： 该函数在向前或向后推进若干天后返回DayOfWeek的实例。

以下程序说明了上述方法：

程序 1 :

// Java Program Demonstrate plus()
// method of DayOfWeek
import java.time.DayOfWeek;
  
class DayOfWeekExample {
    public static void main(String[] args)
    {
        // Getting an instance of DayOfWeek from int value
        DayOfWeek dayOfWeek = DayOfWeek.of(2);
  
        // Printing the day of the week
        // and its Int value
        System.out.println("Day of the Week : "
                           + dayOfWeek.name()
                           + " - "
                           + dayOfWeek.getValue());
  
        // Number of days to advance
        long adv = 10;
  
        // Advancing the day
        dayOfWeek = dayOfWeek.plus(adv);
  
        // Printing the day of the week and its
        // Int value after adv days
        System.out.println("Day of the Week after "
                           + adv + " days: "
                           + dayOfWeek.name() + " - "
                           + dayOfWeek.getValue());
    }
}

输出:

Day of the Week : TUESDAY - 2
Day of the Week after 10 days: FRIDAY - 5

程序2

// Java Program Demonstrate plus()
// method of DayOfWeek
import java.time.DayOfWeek;
  
class DayOfWeekExample {
    public static void main(String[] args)
    {
        // Getting an instance of DayOfWeek
        // from int value
        DayOfWeek dayOfWeek = DayOfWeek.of(7);
  
        // Printing the day of the week
        // and its Int value
        System.out.println("Day of the Week : "
                           + dayOfWeek.name()
                           + " - "
                           + dayOfWeek.getValue());
  
        // Number of days to advance
        long adv = -3;
  
        // Advancing the day
        dayOfWeek = dayOfWeek.plus(adv);
  
        // Printing the day of the week and its
        // Int value after adv days
        System.out.println("Day of the Week after "
                           + adv + " days: "
                           + dayOfWeek.name()
                           + " - "
                           + dayOfWeek.getValue());
    }
}

输出:

Day of the Week : SUNDAY - 7
Day of the Week after -3 days: THURSDAY - 4

参考资料: https://docs.oracle.com/javase/8/docs/api/java/time/DayOfWeek.html#plus-long-