java.util.Calendar clear()方法

java.util.Calendar.add() 方法设置给定的日历字段值和未定义此Calendar的时间值。Calendar实现类可以将默认字段值用于日期和时间计算。

1 语法

public final void clear(int field)

2 参数

field：设置为未定义的日历字段。

3 返回值

无

4 示例1

package com.yiidian;

/**

* 一点教程网： http://www.yiidian.com

*/

/**

* java.util.Calendar clear()方法的例子

*/

import java.util.Calendar;

public class CalendarClearExample1 {

public static void main(String[] args) {

// create a calendar

Calendar cal = (Calendar) Calendar.getInstance();

// display the current date and time

System.out.println("Current Calendar Date: " + cal.getTime());

// use clear method to set year as undefined.

cal.clear(Calendar.YEAR);

// print the result

System.out.println("The calendar shows : " + cal.getTime());

}

}

输出结果为：

Current Calendar Date: Mon Jul 30 06:35:54 PDT 2018

The calendar shows : Thu Jul 30 06:35:54 PDT 1970

5 示例2

package com.yiidian;

/**

* 一点教程网： http://www.yiidian.com

*/

/**

* java.util.Calendar clear()方法的例子

*/

import java.util.Calendar;

public class CalendarclearExample2 {

public static void main(String[] args) {

// create a calendar

Calendar cal = (Calendar) Calendar.getInstance();

// display the current date and time

System.out.println("Current Calendar Date: " + cal.getTime());

// use clear method to set month as undefined.

cal.clear(Calendar.MONTH);

// print the result

System.out.println("The calendar shows : " + cal.getTime());

}

}

输出结果为：

Current Calendar Date: Mon Jul 30 06:39:17 PDT 2018

The calendar shows : Tue Jan 30 06:39:17 PST 2018

6 示例3

package com.yiidian;

/**

* 一点教程网： http://www.yiidian.com

*/

/**

* java.util.Calendar clear()方法的例子

*/

import java.util.Calendar;

public class CalendarClearExample3 {

public static void main(String[] args) {

// create a calendar

Calendar cal = (Calendar) Calendar.getInstance();

// display the current date and time

System.out.println("Current Calendar Date: " + cal.getTime());

// use clear method to set month as undefined.

cal.clear(Calendar.DAY_OF_MONTH);

// print the result

System.out.println("The calendar shows : " + cal.getTime());

cal.clear(Calendar.HOUR);

cal.clear(Calendar.MINUTE);

cal.clear(Calendar.SECOND);

// print the result

System.out.println("The calendar shows : " + cal.getTime());

}

}

输出结果为：

Current Calendar Date: Mon Jul 30 06:45:15 PDT 2018

The calendar shows : Mon Jul 30 06:45:15 PDT 2018

The calendar shows : Mon Jul 30 06:00:00 PDT 2018

7 示例4

package com.yiidian;

/**

* 一点教程网： http://www.yiidian.com

*/

/**

* java.util.Calendar clear()方法的例子

*/

import java.util.Calendar;

public class CalendarClearExample4 {

public static void main(String[] args) {

// create a calendar

Calendar cal = (Calendar) Calendar.getInstance();

// display the current date and time

System.out.println("Current Calendar Date: " + cal.getTime());

cal.clear(Calendar.HOUR);

cal.clear(Calendar.MINUTE);

cal.clear(Calendar.SECOND);

// print the result

System.out.println("The calendar shows : " + cal.getTime());

}

}

输出结果为：

Current Calendar Date: Mon Jul 30 06:48:47 PDT 2018

The calendar shows : Mon Jul 30 06:00:00 PDT 2018