Java的ArrayList 与 LinkedList

数组是存储在连续内存位置的项目的集合。这个想法是将多个相同类型的项目存储在一起。但是，数组的局限性在于数组的大小是预定义和固定的。有多种方法可以解决这个问题。在本文中，讨论了为解决此问题而实现的两个类ArrayList和LinkedList之间的区别。

数组列表

ArrayList 是集合框架的一部分。它存在于Java.util包中，并在Java为我们提供动态数组。虽然，它可能比标准数组慢，但在需要对数组进行大量操作的程序中很有帮助。我们可以动态添加和删除项目。它会自动调整大小。下面通过一个例子来演示ArrayList的实现。

// Java program to demonstrate the
// working of an ArrayList
  
import java.io.*;
import java.util.*;
  
class GFG {
  
    public static void main(String[] args)
    {
  
        // Declaring an ArrayList
        ArrayList arrli
            = new ArrayList();
  
        // Appending the new elements
        // at the end of the list
        for (int i = 1; i <= 5; i++)
            arrli.add(i);
  
        // Printing the ArrayList
        System.out.println(arrli);
  
        // Removing an element from the
        // List
        arrli.remove(3);
  
        // Printing the ArrayList after
        // removing the element
        System.out.println(arrli);
    }
}

输出：

[1, 2, 3, 4, 5]
[1, 2, 3, 5]

链表

此类实现LinkedList 数据结构。链表是线性数据结构，其中元素不存储在连续位置，每个元素都是一个单独的对象，具有数据部分和地址部分。这些元素使用指针和地址链接。每个元素称为一个节点。由于插入和删除的动态性和易用性，它们比数组更受欢迎。下面通过一个例子来演示LinkedList的实现。

// Java program to demonstrate the
// working of a LinkedList
import java.util.*;
  
public class Test {
    public static void main(String args[])
    {
        // Creating an object of the
        // class linked list
        LinkedList object
            = new LinkedList();
  
        // Adding the elements to the
        // linked list
        object.add("A");
        object.add("B");
        object.addLast("C");
  
        System.out.println(object);
  
        // Removing elements from the
        // list
        object.remove("B");
        object.removeFirst();
  
        System.out.println("Linked list after "
                           + "deletion: " + object);
    }
}

输出：

[A, B, C]
Linked list after deletion: [C]

JavaArrayList和LinkedList的区别

ArrayList	LinkedList
This class uses a dynamic array to store the elements in it. With the introduction of generics, this class supports the storage of all types of objects.	This class uses a doubly linked list to store the elements in it. Similar to the ArrayList, this class also supports the storage of all types of objects.
Manipulating ArrayList takes more time due to the internal implementation. Whenever we remove an element, internally, the array is traversed and the memory bits are shifted.	Manipulating LinkedList takes less time compared to ArrayList because, in a doubly-linked list, there is no concept of shifting the memory bits. The list is traversed and the reference link is changed.
This class implements a List interface. Therefore, this acts as a list.	This class implements both the List interface and the Deque interface. Therefore, it can act as a list and a deque.
This class works better when the application demands storing the data and accessing it.	This class works better when the application demands manipulation of the stored data.