Java Calendar computeFields()用法及代碼示例

Calendar類中的computeFields()方法用於將當前毫秒時間值time轉換為field []中提到的日曆字段值。

注意：這允許將為日曆對象設置的新時間與日曆字段值同步。

用法:

protected abstract void computeFields()

參數：該方法不帶任何參數。

返回值：該方法不返回任何值。

以下示例程序旨在說明Calendar類的computeFields()方法的用法：
示例1:

// Java Code to illustrate 
// computeFields() Method 
  
import java.util.*; 
  
public class CalendarClassDemo 
    extends GregorianCalendar { 
    public static void main(String args[]) 
    { 
        // Creating calendar object 
        CalendarClassDemo calndr = new CalendarClassDemo(); 
  
        // Displaying the current date 
        System.out.println("The Current "
                           + "date is: " + calndr.getTime()); 
  
        // Clearing the calendar 
        calndr.clear(); 
  
        // Set a new year and call 
        // computeFields() 
        calndr.set(GregorianCalendar.YEAR, 2016); 
        calndr.computeFields(); 
  
        // Displaying the current date 
        System.out.println("The recent"
                           + " date is: " + calndr.getTime()); 
    } 
}

輸出：

The Current date is: Wed Feb 13 16:15:15 UTC 2019
The recent date is: Wed Feb 13 16:15:15 UTC 2019

示例2:

// Java Code to illustrate 
// computeFields() Method 
  
import java.util.*; 
  
public class CalendarClassDemo 
    extends GregorianCalendar { 
    public static void main(String args[]) 
    { 
        // Creating calendar object 
        CalendarClassDemo calndr = new CalendarClassDemo(); 
  
        // Displaying the current date 
        System.out.println("The Current "
                           + "date is: " + calndr.getTime()); 
  
        // Clearing the calendar 
        calndr.clear(); 
  
        // Set a new year and call 
        // computeFields() 
        calndr.set(GregorianCalendar.YEAR, 2000); 
        calndr.computeFields(); 
  
        // Displaying the current date 
        System.out.println("The recent"
                           + " date is: " + calndr.getTime()); 
    } 
}

輸出：

The Current date is: Wed Feb 13 16:15:18 UTC 2019
The recent date is: Wed Feb 13 16:15:18 UTC 2019

參考： https://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html#computeFields()

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注：本文由純淨天空篩選整理自Chinmoy Lenka大神的英文原創作品 Calendar computeFields() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。