Java Month adjustInto()方法

java.time.Month ENUM的adjustInto()方法是Java中的一个内置函数，它接收一个指定日期的Temporal对象，并返回一个与输入的可观察类型相同的新Temporal对象，其中的月份被替换成这个年月。

方法声明 :

public Temporal adjustInto(Temporal temporal)

语法:

Temporal newLocalDate = Month.ANYMONTH.adjustInto(Temporal temporal)

参数 ：该方法以temporal为参数，其中。

• temporal – 是要调整的指定日期。
• ANYMONTH – 是指定的要调整的日期的月份，例如，一月，二月，等等。
• newLocalDate – 是修改后的日期。

返回值 ：该函数返回一个调整后的时间对象，它是根据指定的月份调整的日期。

异常情况

• DateTimeException : 如果不可能进行调整，该方法会抛出这个异常。
• ArithmeticException ：如果发生数字溢出，则抛出此异常。

下面的程序说明了上述方法。

程序1 :

import java.time.*;
import java.time.Month;
import java.time.temporal.Temporal;
  
class DayOfWeekExample {
    public static void main(String[] args)
    {
        // Set a Local Date whose month is found
        LocalDate localDate1
            = LocalDate.of(1947, Month.AUGUST, 15);
  
        // Find the month from the Local Date
        Month monthOfYear1
            = Month.from(localDate1);
  
        // Printing the Local Date
        System.out.println(localDate1
                           + " which is "
                           + monthOfYear1.name());
  
        // Adjust the month to JANUARY from AUGUST
        Temporal localDate2
            = Month.JANUARY
                  .adjustInto(localDate1);
  
        // Find the day from the new Local date
        Month monthOfYear2
            = Month.from(localDate2);
  
        // Printing the new Local Date
        System.out.println(localDate2
                           + " which is "
                           + monthOfYear2.name());
    }
}

输出。

1947-08-15 which is AUGUST
1947-01-15 which is JANUARY

程序2 :

import java.time.*;
import java.time.Month;
import java.time.temporal.Temporal;
  
class DayOfWeekExample {
    public static void main(String[] args)
    {
        // Set a Local Date whose month is found
        LocalDate localDate1
            = LocalDate.of(2019, Month.MARCH, 18);
  
        // Find the month from the Local Date
        Month monthOfYear1
            = Month.from(localDate1);
  
        // Printing the Local Date
        System.out.println(localDate1
                           + " which is "
                           + monthOfYear1.name());
  
        // Adjust the month to December from March
        Temporal localDate2
            = Month.DECEMBER
                  .adjustInto(localDate1);
  
        // Find the day from the new Local date
        Month monthOfYear2
            = Month.from(localDate2);
  
        // Printing the new Local Date
        System.out.println(localDate2
                           + " which is "
                           + monthOfYear2.name());
    }
}

输出。

2019-03-18 which is MARCH
2019-12-18 which is DECEMBER

参考资料 : https://docs.oracle.com/javase/8/docs/api/java/time/Month.html#adjustInto-java.time.temporal.Temporal-