LinkedList公共对象peek()方法 (LinkedList public Object peek() method)

• This method is available in package java.util.LinkedList.peek().

  软件包java.util.LinkedList.peek()中提供了此方法。

• This method is used to retrieve the head element of the linked list without removing the head element.

  此方法用于检索链接列表的head元素，而无需删除head元素。

• If the list is empty then it will return null.

  如果列表为空，则它将返回null。

Syntax:

句法：

    public Object peek(){
}

Parameter(s):

参数：

In this method, we don’t pass any object as a parameter in the method but it returns the first object from the linked list.

在此方法中，我们不会在该方法中传递任何对象作为参数，但是它将返回链表中的第一个对象。

Return value:

返回值：

The return type of this method is not void that means this method returns head object or element (i.e. It returns the only first element in the list). If the list is empty then it will not give any exception.

该方法的返回类型不是void，这意味着该方法返回头对象或元素(即，它返回列表中唯一的第一个元素)。 如果列表为空，则不会给出任何异常。

Java程序演示LinkedList peek()方法的示例 (Java program to demonstrate example of LinkedList peek() method)

import java.util.LinkedList;
public class LinkList {
public static void main(String[] args) {
LinkedList list = new LinkedList();
// use add() method to add elements in the list 
list.add(10);
list.add(20);
list.add(30);
list.add(40);
list.add(50);
//  Current list Output
System.out.println("The Current list is:" + list);
//  Using peek() method it will retrieve first element 
// without removing the element from the list  
System.out.println("The First Element In The List is:" + list.peekFirst());
}
}

Output

输出量

D:\Programs>javac LinkList.java
D:\Programs>java LinkList
The Current list is:[10, 20, 30, 40, 50]
The First Element In The List is:10

翻译自: https://www.includehelp.com/java/linkedlist-public-object-peek-method-with-example.aspx