Java Date clone()方法及实例

Java中Date类的clone()方法返回传递的Date对象的副本。这个副本只是给定Date对象的一个浅层拷贝。

语法：

public Object clone()

参数： 该方法不接受任何参数。

返回值： 该方法返回一个对象的克隆。

以下程序说明了clone()方法的使用：

例子1：

// Java code to demonstrate
// clone() method of Date class
 
import java.util.Date;
import java.util.Calendar;
 
public class GfG {
    public static void main(String args[])
    {
 
        // Creating a Calendar object
        Calendar c1 = Calendar.getInstance();
 
        // Set Month
        // MONTH starts with 0 i.e. ( 0 - Jan)
        c1.set(Calendar.MONTH, 11);
 
        // Set Date
        c1.set(Calendar.DATE, 05);
 
        // Set Year
        c1.set(Calendar.YEAR, 1996);
 
        // Creating a date object
        // with specified time.
        Date dateOne = c1.getTime();
 
        Object dateTwo = dateOne.clone();
 
        System.out.println("Original Date: "
                           + dateOne.toString());
        System.out.println("Cloned Date: "
                           + dateTwo.toString());
    }
}

输出

Original Date: Thu Dec 05 05:39:04 UTC 1996
Cloned Date: Thu Dec 05 05:39:04 UTC 1996

例2：

// Java code to demonstrate
// clone() method of Date class
 
import java.util.Date;
import java.util.Calendar;
 
public class GfG {
    public static void main(String args[])
    {
 
        // Creating a Calendar object
        Calendar c1 = Calendar.getInstance();
 
        // Set Month
        // MONTH starts with 0 i.e. ( 0 - Jan)
        c1.set(Calendar.MONTH, 00);
 
        // Set Date
        c1.set(Calendar.DATE, 30);
 
        // Set Year
        c1.set(Calendar.YEAR, 2019);
 
        // Creating a date object
        // with specified time.
        Date dateOne = c1.getTime();
 
        Object dateTwo = dateOne.clone();
 
        System.out.println("Original Date: "
                           + dateOne.toString());
        System.out.println("Cloned Date: "
                           + dateTwo.toString());
    }
}

输出

Original Date: Wed Jan 30 05:39:10 UTC 2019
Cloned Date: Wed Jan 30 05:39:10 UTC 2019

参考资料: https://docs.oracle.com/javase/8/docs/api/java/util/Date.html#clone-