Detailed example of using Queue in Java

The examples in this article describe the usage of Java's built-in queue class Queue, and share it with everyone for your reference

Queue is a special linear table, which only allows deletion at the front end of the table operation, while the insert operation is performed on the backend of the table.

The LinkedList class implements the Queue interface, so we can use LinkedList as a Queue.

The following examples demonstrate the usage of Queue:

/*
 author by w3cschool.cc
 Main.java
 */
import java.util.LinkedList;
import java.util.Queue;
public class Main {
 public static void main(String[] args) {
  //add()和remove()方法在失败的时候会抛出异常(不推荐)
  Queue<String> queue = new LinkedList<String>();
  //添加元素
  queue.offer("a");
  queue.offer("b");
  queue.offer("c");
  queue.offer("d");
  queue.offer("e");
  for(String q : queue){
   System.out.println(q);
  }
  System.out.println("===");
  System.out.println("poll="+queue.poll()); //返回第一个元素，并在队列中删除
  for(String q : queue){
   System.out.println(q);
  }
  System.out.println("===");
  System.out.println("element="+queue.element()); //返回第一个元素 
  for(String q : queue){
   System.out.println(q);
  }
  System.out.println("===");
  System.out.println("peek="+queue.peek()); //返回第一个元素 
  for(String q : queue){
   System.out.println(q);
  }
 }
}

The output result of running the above code is:

a
b
c
d
e
===
poll=a
b
c
d
e
===
element=b
b
c
d
e
===
peek=b
b
c
d
e

【Related recommendations】

1. Java Free Video Tutorial

2. Alibaba Java Development Manual

3. Comprehensive analysis of Java annotations

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