Java Java.util.ArrayList.clone()用法及代碼示例

描述

這個java.util.ArrayList.clone()返回這個 ArrayList 實例的淺拷貝(即元素本身不被複製)。

聲明

以下是聲明java.util.ArrayList.clone()方法

public Object clone()

參數

NA

返回值

此方法返回此 ArrayList 實例的副本。

異常

NA

示例

下麵的例子展示了 java.util.Arraylist.clone() 方法的用法。

package com.tutorialspoint;

import java.util.ArrayList;

public class ArrayListDemo {
   public static void main(String args[]) {

      // create an empty array list
      ArrayList<StringBuilder> arrlist1 = new ArrayList<StringBuilder>();

      // use add for new value
      arrlist1.add(new StringBuilder("Learning-"));

      // using clone to affect the objects pointed to by the references.
      ArrayList arrlist2 = (ArrayList) arrlist1.clone();

      // appending the string
      StringBuilder strbuilder = arrlist1.get(0);
      strbuilder.append("list1, list2-both pointing to the same StringBuilder");

      System.out.println("The 1st list prints:");

      // both lists will print the same value, printing list1
      for (int i = 0; i < arrlist1.size(); i++) {
         System.out.print(arrlist1.get(i) + " ");
      }

      System.out.println("The 2nd list prints the same i.e:");

      // both lists will print the same value, printing list2
      for (int i = 0; i < arrlist2.size(); i++) {
         System.out.print(arrlist2.get(i));
      }
   }
}

讓我們編譯並運行上麵的程序，這將產生以下結果——

The 1st list prints:
Learning-list1, list2 - both pointing to the same StringBuilder
The 2nd list prints the same i.e:
Learning-list1, list2 - both pointing to the same StringBuilder