Java 中的 Java.util.GregorianCalendar 类

原文:https://www . geesforgeks . org/Java-util-gregoriancalendar-class-Java/

先决条件: java.util.Locale 、 java.util.TimeZone 、Calendar . get() Gregorian Calendar是 Calendar 的一个具体子类(其所有继承成员的实现都来自接口或抽象类)，该子类实现了我们所熟悉的最广泛使用的公历。

Java . util . gregoriancalendar vs Java . util . calendar

公历和历类的主要区别在于历类是抽象类，不能实例化。因此日历类的一个对象被初始化为:

Calendar cal = Calendar.getInstance();

这里，一个名为日历类的 cal 的对象被初始化为默认区域和时区中的当前日期和时间。然而，格列高利根达类是一个具体的类，可以被实例化。因此格列高利安卡列达尔类的一个对象被初始化为:

GregorianCalendar gcal = new GregorianCalendar();

这里，一个名为的对象被初始化为默认区域和时区中的当前日期和时间。 字段定义:****

GregorianCalendar Class defines two fields:
AD : referring to the common era(***anno Domini***)
BC : referring to before common era(Before Christ)

构造函数:有多个用于格列高里卡列达尔对象的构造函数。广义上来说，公历的构造函数要么在默认区域和时区中用用户指定的日期和/或时间初始化对象，要么在用户指定的区域和/或时区中用默认的日期和时间初始化对象。这些措施如下:

| **建造师签名** | **描述** | | --- | --- | | **公历日历（）** | 使用默认区域设置和时区中的当前日期和时间初始化对象 | | **公历**T2**年**T5**日，int**T8**月**T11**日，int**T14**日** | 使用在默认区域设置和时区中作为参数传递的日期集初始化对象 | | **公历**T2**年**T5**日，int**T8**月**T11**日，int**T14**日** | 使用在默认区域设置和时区中作为参数传递的日期和时间集初始化对象 | | **公历(int** ***【年】****、int****【月】*** **、int** | 使用在默认区域设置和时区中作为参数传递的日期和更具体的时间集初始化对象 | | **公历(本地** ***本地*** **)** | 使用默认时区中的当前日期和时间以及作为参数传递的区域设置初始化对象 | | **格里高利安卡雷达(时区** ***时区*** **)** | 使用默认区域设置中的当前日期和时间以及作为参数传递的时区初始化对象 | | **公历(time zone*****【time zone】****、本地****【本地】*** **)** | 使用区域设置中的当前日期和时间以及作为参数传递的时区初始化对象 |

方法从()、到中地时间()、在 JDK 8 号引种。

Java 语言(一种计算机语言，尤用于创建网站)

// Java Program to show that Calendar class with
// default instantiation and GregorianCalendar class
// with default constructor is basically the same as both
// return the Gregorian Calendar for the default
// date, time, time zone and locale

import java.util.Calendar;
import java.util.GregorianCalendar;

class CalendarGFG {
    public static void main(String[] args)
    {
        // Creating an object of Calendar Class
        Calendar cal = Calendar.getInstance();

        /* Creating an object of
             GregorianCalendar Class */
        GregorianCalendar gcal = new GregorianCalendar();

        /* Displaying Current Date using
             Calendar Class */
        System.out.println("Calendar date: "
                           + cal.getTime());

        /* Displaying Current Date using
             GregorianCalendar Class */
        System.out.print("Gregorian date: "
                         + gcal.getTime());
    } // end of main function
} // end of class

输出:

Calendar date: Sat Apr 28 13:36:37 UTC 2018
Gregorian date: Sat Apr 28 13:36:37 UTC 2018

举例演示各种构造函数的用法: 1。使用默认构造函数

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate simple GregorianCalendar
// operations
import java.util.Locale;
import java.util.TimeZone;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class GregorianCalendarGFG {
    public static void main(String args[])
    {
        // declaring an array to store month abbreviations
        String month[] = { "Jan", "Feb", "Mar", "Apr",
                           "May", "Jun", "Jul", "Aug",
                           "Sep", "Oct", "Nov", "Dec" };

        // declaring an array to store AM or PM
        String amPm[] = { "AM", "PM" };

        /* Creating an object of GregorianCalendar class
             using default constructor*/
        GregorianCalendar gcal = new GregorianCalendar();

        // displaying the date, time, time zone and locale
        System.out.print("Date: "
                         + month[gcal.get(Calendar.MONTH)] + " "
                         + gcal.get(Calendar.DATE) + ", "
                         + gcal.get(Calendar.YEAR) + "\n"
                         + "Time: "
                         + gcal.get(Calendar.HOUR) + ":"
                         + gcal.get(Calendar.MINUTE) + ":"
                         + gcal.get(Calendar.SECOND) + " "
                         + amPm[gcal.get(Calendar.AM_PM)] + "\n"
                         + "Time Zone: " + gcal.getTimeZone().getDisplayName()
                         + "\n"
                         + "Locale: "
                         + Locale.getDefault().getDisplayName());
    } // end of main function
} // end of class

输出:

Date: Apr 30, 2018
Time: 10:21:51 PM
Time Zone: Coordinated Universal Time
Locale: English (United States)

2。以年、月、日、月为参数:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate simple GregorianCalendar
// operations
import java.util.Locale;
import java.util.TimeZone;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class GregorianCalendarGFG {
    public static void main(String args[])
    {
        // declaring an array to store month abbreviations
        String month[] = { "Jan", "Feb", "Mar", "Apr",
                           "May", "Jun", "Jul", "Aug",
                           "Sep", "Oct", "Nov", "Dec" };

        // declaring an array to store AM or PM
        String amPm[] = { "AM", "PM" };

        /* Creating an object of GregorianCalendar class
           by specifying year, month and dayOfMonth */
        GregorianCalendar gcal = new GregorianCalendar(2018, 3, 30);

        // displaying the date, time, time zone and locale
        System.out.print("Date: "
                         + month[gcal.get(Calendar.MONTH)] + " "
                         + gcal.get(Calendar.DATE) + ", "
                         + gcal.get(Calendar.YEAR) + "\n"
                         + "Time: "
                         + gcal.get(Calendar.HOUR) + ":"
                         + gcal.get(Calendar.MINUTE) + ":"
                         + gcal.get(Calendar.SECOND) + " "
                         + amPm[gcal.get(Calendar.AM_PM)] + "\n"
                         + "Time Zone: " + gcal.getTimeZone().getDisplayName()
                         + "\n"
                         + "Locale: "
                         + Locale.getDefault().getDisplayName());
    } // end of main function
} // end of class

输出:

Date: Apr 30, 2018
Time: 0:0:0 AM
Time Zone: Coordinated Universal Time
Locale: English (United States)

3。年、月、日、月、时、分:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate simple GregorianCalendar
// operations
import java.util.Locale;
import java.util.TimeZone;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class GregorianCalendarGFG {
    public static void main(String args[])
    {
        // declaring an array to store month abbreviations
        String month[] = { "Jan", "Feb", "Mar", "Apr",
                           "May", "Jun", "Jul", "Aug",
                           "Sep", "Oct", "Nov", "Dec" };

        // declaring an array to store AM or PM
        String amPm[] = { "AM", "PM" };

        /* Creating an object of GregorianCalendar class
           by specifying year, month, dayOfMonth,
           hourOfDay and minute */
        GregorianCalendar gcal = new GregorianCalendar(2018, 3, 30, 10, 21);

        // displaying the date, time, time zone and locale
        System.out.print("Date: "
                         + month[gcal.get(Calendar.MONTH)] + " "
                         + gcal.get(Calendar.DATE) + ", "
                         + gcal.get(Calendar.YEAR) + "\n"
                         + "Time: "
                         + gcal.get(Calendar.HOUR) + ":"
                         + gcal.get(Calendar.MINUTE) + ":"
                         + gcal.get(Calendar.SECOND) + " "
                         + amPm[gcal.get(Calendar.AM_PM)] + "\n"
                         + "Time Zone: " + gcal.getTimeZone().getDisplayName()
                         + "\n"
                         + "Locale: "
                         + Locale.getDefault().getDisplayName());
    } // end of main function
} // end of class

输出:

Date: Apr 30, 2018
Time: 10:21:0 AM
Time Zone: Coordinated Universal Time
Locale: English (United States)

4。通过年、月、日、月、时、分、秒:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate simple GregorianCalendar
// operations
import java.util.Locale;
import java.util.TimeZone;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class GregorianCalendarGFG {
    public static void main(String args[])
    {
        // declaring an array to store month abbreviations
        String month[] = { "Jan", "Feb", "Mar", "Apr",
                           "May", "Jun", "Jul", "Aug",
                           "Sep", "Oct", "Nov", "Dec" };

        // declaring an array to store AM or PM
        String amPm[] = { "AM", "PM" };

        /* Creating an object of GregorianCalendar class
           by specifying year, month, dayOfMonth,
           hourOfDay, minute and second */
        GregorianCalendar gcal = new GregorianCalendar(2018, 3, 30, 10, 21, 51);

        // displaying the date, time, time zone and locale
        System.out.print("Date: "
                         + month[gcal.get(Calendar.MONTH)] + " "
                         + gcal.get(Calendar.DATE) + ", "
                         + gcal.get(Calendar.YEAR) + "\n"
                         + "Time: "
                         + gcal.get(Calendar.HOUR) + ":"
                         + gcal.get(Calendar.MINUTE) + ":"
                         + gcal.get(Calendar.SECOND) + " "
                         + amPm[gcal.get(Calendar.AM_PM)] + "\n"
                         + "Time Zone: " + gcal.getTimeZone().getDisplayName()
                         + "\n"
                         + "Locale: "
                         + Locale.getDefault().getDisplayName());
    } // end of main function
} // end of class

输出:

Date: Apr 30, 2018
Time: 10:21:51 AM
Time Zone: Coordinated Universal Time
Locale: English (United States)

5。通过将时区作为参数传递:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate simple GregorianCalendar
// operations
import java.util.TimeZone;
import java.util.Locale;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class GregorianCalendarTest {
    public static void main(String args[])
    {
        // declaring an array to store month abbreviations
        String month[] = { "Jan", "Feb", "Mar", "Apr",
                           "May", "Jun", "Jul", "Aug",
                           "Sep", "Oct", "Nov", "Dec" };

        // declaring an array to store AM or PM
        String amPm[] = { "AM", "PM" };

        /* Creating an object of TimeZone class to create
             an object of GregorianCalendar class to assign
             an user defined time zone (GMT + 5:30)*/
        TimeZone tz = TimeZone.getTimeZone("GMT+5:30");
        GregorianCalendar gcal = new GregorianCalendar(tz);

        // displaying the date, time, time zone and locale
        System.out.print("Date: "
                         + month[gcal.get(Calendar.MONTH)] + " "
                         + gcal.get(Calendar.DATE) + ", "
                         + gcal.get(Calendar.YEAR) + "\n"
                         + "Time: "
                         + gcal.get(Calendar.HOUR) + ":"
                         + gcal.get(Calendar.MINUTE) + ":"
                         + gcal.get(Calendar.SECOND) + " "
                         + amPm[gcal.get(Calendar.AM_PM)] + "\n"
                         + "Time Zone: " + gcal.getTimeZone().getDisplayName()
                         + "\n"
                         + "Locale: " + Locale.getDefault().getDisplayCountry());
    } // end of main function
} // end of class

输出:

Date: May 1, 2018
Time: 4:24:7 AM
Time Zone: GMT+05:30
Locale: United States

6。通过将区域设置作为参数传递:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate simple GregorianCalendar
// operations
import java.util.TimeZone;
import java.util.Locale;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class GregorianCalendarTest {
    public static void main(String args[])
    {
        // declaring an array to store month abbreviations
        String month[] = { "Jan", "Feb", "Mar", "Apr",
                           "May", "Jun", "Jul", "Aug",
                           "Sep", "Oct", "Nov", "Dec" };

        // declaring an array to store AM or PM
        String amPm[] = { "AM", "PM" };

        /* Creating an object of Locale class to create
             an object of GregorianCalendar class to assign
             an user defined locale (India)*/
        Locale l = new Locale("en", "IN");
        GregorianCalendar gcal = new GregorianCalendar(l);

        // displaying the date, time, time zone and locale
        System.out.print("Date: "
                         + month[gcal.get(Calendar.MONTH)] + " "
                         + gcal.get(Calendar.DATE) + ", "
                         + gcal.get(Calendar.YEAR) + "\n"
                         + "Time: "
                         + gcal.get(Calendar.HOUR) + ":"
                         + gcal.get(Calendar.MINUTE) + ":"
                         + gcal.get(Calendar.SECOND) + " "
                         + amPm[gcal.get(Calendar.AM_PM)] + "\n"
                         + "Time Zone: "
                         + gcal.getTimeZone().getDisplayName()
                         + "\n"
                         + "Locale: " + l.getDisplayCountry());
    } // end of main function
} // end of class

输出:

Date: Apr 30, 2018
Time: 10:58:30 PM
Time Zone: Coordinated Universal Time
Locale: India

7。通过将时区和区域设置作为参数传递:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate simple GregorianCalendar
// operations
import java.util.TimeZone;
import java.util.Locale;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class GregorianCalendarTest {
    public static void main(String args[])
    {
        // declaring an array to store month abbreviations
        String month[] = { "Jan", "Feb", "Mar", "Apr",
                           "May", "Jun", "Jul", "Aug",
                           "Sep", "Oct", "Nov", "Dec" };

        // declaring an array to store AM or PM
        String amPm[] = { "AM", "PM" };

        /* Creating an object of TimeZone class and Locale
             class to create an object of GregorianCalendar
             class to assign an user defined time zone
             (GMT + 5:30) and locale (India)*/
        TimeZone tz = TimeZone.getTimeZone("GMT+5:30");
        Locale l = new Locale("en", "IN");
        GregorianCalendar gcal = new GregorianCalendar(tz, l);

        // displaying the date, time, time zone and locale
        System.out.print("Date: "
                         + month[gcal.get(Calendar.MONTH)] + " "
                         + gcal.get(Calendar.DATE) + ", "
                         + gcal.get(Calendar.YEAR) + "\n"
                         + "Time: "
                         + gcal.get(Calendar.HOUR) + ":"
                         + gcal.get(Calendar.MINUTE) + ":"
                         + gcal.get(Calendar.SECOND) + " "
                         + amPm[gcal.get(Calendar.AM_PM)] + "\n"
                         + "Time Zone: "
                         + gcal.getTimeZone().getDisplayName()
                         + "\n"
                         + "Locale: " + l.getDisplayCountry());
    } // end of main function
} // end of class

输出:

Date: May 1, 2018
Time: 4:34:59 AM
Time Zone: GMT+05:30
Locale: India

参考: GregorianCalendar(Java 平台 SE 8)–甲骨文帮助中心

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