Detaillierte Erläuterung von LinkedList in Java-Sammlungen

public class Hello {

    public static void main(String[] args) {
        testLinkedListAPIs() ;
        useLinkedListAsLIFO();
        useLinkedListAsFIFO();
    }

    private static void testLinkedListAPIs()
    {
        String val = null;
        LinkedList llist = new LinkedList();
        //添加是哪个元素
        llist.add("1");
        llist.add("2");
        llist.add("3");
        llist.add(1, "4");//在第一个元素后面插入4
        System.out.println("\nTest \"addFirst(), removeFirst(), getFirst()\"");
        llist.addFirst("10");//将10插入并作为第一个元素
        System.out.println("llist:"+llist);
        System.out.println("llist.removeFirst():"+llist.removeFirst());//删除掉第一个元素
        System.out.println("llist:"+llist);
        System.out.println("llist.getFirst():"+llist.getFirst());//获得第一个元素
        System.out.println("\nTest \"offerFirst(), pollFirst(), peekFirst()\"");
        llist.offerFirst("10");//添加第一个元素
        System.out.println("llist:"+llist);
        System.out.println("llist.pollFirst():"+llist.pollFirst());//去掉第一个元素
        System.out.println("llist:"+llist);
        System.out.println("llist.peekFirst():"+llist.peekFirst());//读取第一个元素
        System.out.println("\nTest \"addLast(), removeLast(), getLast()\"");
        llist.addLast("20");//链尾添加元素20
        System.out.println("llist:"+llist);
        System.out.println("llist.removeLast():"+llist.removeLast());//删掉链尾元素20
        System.out.println("llist:"+llist);
        System.out.println("llist.getLast():"+llist.getLast());//读取链尾元素
        System.out.println("\nTest \"offerLast(), pollLast(), peekLast()\"");
        llist.offerLast("20");//添加链尾元素20
        System.out.println("llist:"+llist);
        System.out.println("llist.pollLast():"+llist.pollLast());//删掉链尾元素20
        System.out.println("llist:"+llist);
        System.out.println("llist.peekLast():"+llist.peekLast());//读取链尾元素
        llist.set(2, "300");//替换第三个元素
        System.out.println("\nget(3):"+llist.get(2));//获得第三个元素

        String[] arr = (String[])llist.toArray(new String[0]);//得到数组
        for (String str:arr)
        {
            System.out.println("str:"+str);
            System.out.println("size:"+llist.size());
            llist.clear();
            System.out.println("isEmpty():"+llist.isEmpty()+"\n");
        }
    }
    private static void useLinkedListAsLIFO()
    {
        System.out.println("\nuseLinkedListAsLIFO");
        LinkedList stack = new LinkedList();
        //类似于栈输入
        stack.push("1");
        stack.push("2");
        stack.push("3");
        stack.push("4");
        System.out.println("stack:"+stack);
        System.out.println("stack.pop():"+stack.pop());//出栈
        System.out.println("stack.peek():"+stack.peek());//只输出栈顶元素并不出栈
        System.out.println("stack:"+stack);
    }

    private static void useLinkedListAsFIFO()
    {
        System.out.println("\nuseLinkedListAsFIFO");
        LinkedList queue = new LinkedList();
        //类似于队列，入队
        queue.add("10");
        queue.add("20");
        queue.add("30");
        queue.add("40");
        System.out.println("queue:"+queue);
        System.out.println("queue.remove():"+queue.remove());//队列出队
        System.out.println("queue.element():"+queue.element());//读取队头，并不删除元素
        System.out.println("queue:"+queue);
    }
}

Test "offerLast(), pollLast(), peekLast()"
llist:[1, 4, 2, 3, 20]
llist.pollLast():20
llist:[1, 4, 2, 3]
llist.peekLast():3
get(3):300
str:1
size:4
isEmpty():true
str:4
size:0
isEmpty():true
str:300
size:0
isEmpty():true
str:3
size:0
isEmpty():true
useLinkedListAsLIFO
stack:[4, 3, 2, 1]
stack.pop():4
stack.peek():3
stack:[3, 2, 1]
useLinkedListAsFIFO
queue:[10, 20, 30, 40]
queue.remove():10
queue.element():20
queue:[20, 30, 40]