Java 日历 clear(int cal_field)方法及实例

Calendar类中的 clear(int cal_field ) 方法用于设置给定的日历字段值和该日历的时间值。
注意：日历类的实现可以使用默认字段值进行日期和时间计算。

语法

public final void clear(int cal_field)

参数： 该方法需要一个整数类型的参数cal_field，它指的是要变成未定义的字段值。

返回值： 该方法不返回任何值。

下面的程序说明了日历类的clear()方法的工作原理：

示例1 :

// Java Code to illustrate clear() Method  import java.util.Calendar;  public class CalendarClassDemo {    public static void main(String args[])    {        // Creating a calendar object        Calendar calndr = Calendar.getInstance();          // Displaying the Current Date        System.out.println("Current Date&Time: "                           + calndr.getTime());          // Clear method for undefining the month        // of the calendar        calndr.clear(Calendar.MONTH);          // Displaying the final result        System.out.println("After clear method: "                           + calndr.getTime());    }}

输出:

Current Date&Time: Wed Mar 27 09:03:26 UTC 2019After clear method: Sun Jan 27 09:03:26 UTC 2019

例2 :

// Java Code to illustrate clear() Method  import java.util.Calendar;  public class CalendarClassDemo {    public static void main(String args[])    {        // Creating a calendar object        Calendar calndr = Calendar.getInstance();          // Displaying the Current Date        System.out.println("Current Date&Time: "                           + calndr.getTime());          // Clear method for undefining the year        // of the calendar        calndr.clear(Calendar.YEAR);          // Displaying the final result        System.out.println("After clear method: "                           + calndr.getTime());    }}

输出:

Current Date&Time: Wed Mar 27 09:03:32 UTC 2019After clear method: Fri Mar 27 09:03:32 UTC 1970

**参考资料: **https://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html#clear(int)