Java MonthDay withDayOfMonth()方法及示例

MonthDay 类的 withDayOfMonth(int dayOfMonth) 方法用于改变MonthDay对象的月日，使用dayOfMonth作为参数传递，之后该方法返回改变后的MonthDay副本。

语法

public MonthDay withDayOfMonth(int dayOfMonth)

参数： 该方法接受 dayOfMonth 作为参数，该参数是在返回的月日中设置的月日，从1到31。

返回值： 该方法返回一个基于该月日的MonthDay，该月日为要求的日期。

异常： 如果月日值无效，或者月日对该月来说是无效的，该方法会抛出 DateTimeException 。

下面的程序说明了withDayOfMonth()方法：

程序1 :

// Java program to demonstrate
// MonthDay.withDayOfMonth() method
  
import java.time.*;
import java.time.temporal.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create a MonthDay object
        MonthDay monthday
            = MonthDay.of(8, 28);
  
        // print instance
        System.out.println("MonthDay before"
                           + " applying method: "
                           + monthday);
  
        // apply withDayOfMonth method
        // of MonthDay class
        MonthDay updatedlocal
            = monthday.withDayOfMonth(21);
  
        // print instance
        System.out.println("MonthDay after"
                           + " applying method: "
                           + updatedlocal);
    }
}

输出。

MonthDay before applying method: --08-28
MonthDay after applying method: --08-21

程序2

// Java program to demonstrate
// MonthDay.withDayOfMonth() method
  
import java.time.*;
import java.time.temporal.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create a MonthDay object
        MonthDay monthday
            = MonthDay.of(10, 31);
  
        // print instance
        System.out.println("MonthDay before"
                           + " applying method: "
                           + monthday);
  
        // apply withDayOfMonth method
        // of MonthDay class
        MonthDay updatedlocal
            = monthday.withDayOfMonth(12);
  
        // print instance
        System.out.println("MonthDay after"
                           + " applying method: "
                           + updatedlocal);
    }
}

输出。

MonthDay before applying method: --10-31
MonthDay after applying method: --10-12

**参考文献: ** https://docs.oracle.com/javase/10/docs/api/java/time/MonthDay.html#withDayOfMonth(int)