Java GregorianCalendar equals()用法及代碼示例

java.util.GregorianCalendar.equals()方法是Java中的內置函數，該函數檢查此GregorianCalendar實例與作為參數傳遞給該函數的Object之間是否相等。僅當指定的Object是具有與此GregorianCalendar實例相同的時間值(距曆元毫秒的偏移量)的GregorianCalendar對象時，它才返回true。

用法:

public boolean equals(Object obj)

參數：該函數接受單個強製性參數obj，該參數將與此GregorianCalendar實例進行比較。

返回值：僅當指定的Object是GregorianCalendar對象並且具有與此實例相同的時間值(距紀元的毫秒偏移)時，此方法才返回true，否則返回false。

例子：

Input : c1 = Mon Jul 23 23:46:14 UTC 2018, c2 = Mon Jul 23 23:46:14 UTC 2018
Output : true

Input : c1 = Mon Jul 23 23:46:14 UTC 2018, c2 = Sun Jul 24 00:02:52 UTC 2022
Output : false

下麵的程序演示了java.util.GregorianCalendar.equals()函數：
示例1:

// Java Program to illustrate the equals() function  
// of GregorianCalendar class 
  
import java.io.*; 
import java.util.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        // Create a new calendar 
        GregorianCalendar c1 = (GregorianCalendar) 
                     GregorianCalendar.getInstance(); 
  
        // Display the current date and time 
        System.out.println("Current Date and Time : "
                           + c1.getTime()); 
  
        // Create a second calendar equal to first one 
        GregorianCalendar c2 =  
              (GregorianCalendar)(Calendar)c1.clone(); 
  
        // Compare the two calendars 
        System.out.println("Both calendars are equal:"
                           + c1.equals(c2)); 
  
        // Adding 15 months to second calender 
        c2.add(GregorianCalendar.MONTH, 15); 
  
        // Display the current date and time 
        System.out.println("Modified Date and Time : "
                           + c2.getTime()); 
  
        // Compare the two calendars 
        System.out.println("Both calendars are equal:"
                           + c1.equals(c2)); 
    } 
}

輸出：

Current Date and Time : Fri Jul 27 12:05:05 UTC 2018
Both calendars are equal:true
Modified Date and Time : Sun Oct 27 12:05:05 UTC 2019
Both calendars are equal:false

示例2:

// Java Program to illustrate the equals() function  
// of GregorianCalendar class 
  
import java.io.*; 
import java.util.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        // Create a new calendar 
        GregorianCalendar c1 = (GregorianCalendar) 
                     GregorianCalendar.getInstance(); 
  
        // Display the current date and time 
        System.out.println("Current Date and Time : "
                           + c1.getTime()); 
  
        // Create a second calendar equal to first one 
        GregorianCalendar c2 =  
             (GregorianCalendar)(Calendar)c1.clone(); 
  
        // Compare the two calendars 
        System.out.println("Both calendars are equal:"
                           + c1.equals(c2)); 
  
        // Changing the Time Zone of c2 
        c2.setTimeZone(TimeZone.getTimeZone("CST")); 
  
        // Compare the two calendars 
        System.out.println("Both calendars are equal:"
                           + c1.equals(c2)); 
    } 
}

輸出：

Current Date and Time : Fri Jul 27 12:05:08 UTC 2018
Both calendars are equal:true
Both calendars are equal:false

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

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注：本文由純淨天空篩選整理自RICHIK BHATTACHARJEE大神的英文原創作品 GregorianCalendar equals() Method in Java。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。