Java中的日历 computeFields() 方法及示例

Calendar类中的computeFields()方法用于当前毫秒时间值time到fields[]中提到的日历字段值的转换操作。

注意：这允许为日历对象设置的新时间与日历字段值同步。

句法：

protected abstract void computeFields()

参数：该方法不带任何参数。

返回值：该方法不返回任何值。

下面的程序说明了 Calendar 类的 computeFields() 方法的工作：
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());
    }
}

输出：

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());
    }
}

输出：

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

参考： https: Java/util/Calendar.html#computeFields()