Java中的向量 clone() 方法及示例

Vector 类的clone()方法用于返回 Object 类提供的该向量的浅表副本。它只是创建向量的副本。副本将引用内部数据数组的克隆，但不会引用原始内部数据数组。

句法：

Vector.clone()

参数：该方法不带任何参数。

返回值：该方法返回一个对象，它只是向量的副本。

抛出异常： CloneNotSupportedException： 如果对象的类不支持 Cloneable 接口，则会引发此异常。

示例 1：

Java

// Java Program to Illustrate clone() method of Vector class
 
// Importing required classes
import java.util.*;
 
// Main class
// VectorDemo
public class GFG {
 
    // Main driver method
    public static void main(String args[])
    {
 
        // Creating an empty Vector by creating object
        // of vector class of string type
        Vector vec_tor = new Vector();
 
        // Adding custom input elements into the vector
        // using add() method
        vec_tor.add("Welcome");
        vec_tor.add("To");
        vec_tor.add("Geeks");
        vec_tor.add("For");
        vec_tor.add("Geeks");
 
        // Print and display all vector elements
        System.out.println("Vector: " + vec_tor);
 
        // Creating another vector to copy by
        // creating an object of Object class
        Object copy_vector = vec_tor.clone();
 
        // Print and display the cloned vector elements
        System.out.println("The cloned vector is: "
                           + copy_vector);
    }
}

输出

Vector: [Welcome, To, Geeks, For, Geeks]
The cloned vector is: [Welcome, To, Geeks, For, Geeks]

示例 2：

Java

// Java Program to Illustrate clone() method of Vector class
 
// Importing required classes
import java.util.*;
 
// Main class
// VectorDemo
public class VectorDemo {
   
    // Main driver method
    public static void main(String args[])
    {
        // Creating an empty Vector by creating
       // object of Vector class of Integer type
        Vector vec_tor = new Vector();
 
        // Add custom input elements for 
        // using add() method
        vec_tor.add(10);
        vec_tor.add(15);
        vec_tor.add(30);
        vec_tor.add(20);
        vec_tor.add(5);
 
        // Print and display the vector elements
        System.out.println("Vector: " + vec_tor);
 
        // Creating another vector to copy by
        // creating object of Object class
        Object copy_vector = (Vector)vec_tor.clone();
 
        // Print and display elements of cloned vector
        System.out.println("The cloned vector is: " + copy_vector);
    }
}

输出

Vector: [10, 15, 30, 20, 5]
The cloned vector is: [10, 15, 30, 20, 5]

Note: In the above examples we have cloned vectors by creating objects of Object class itself as it does provide clone() method. So if object classes are not supporting any cloneable interface then it will not allow to clone and copy vector elements so does it will throw CloneNotSupportedException.