public static void main(String[] args) {
	// ArrayList創(chuàng)建，推薦寫(xiě)法
	// 構(gòu)造一個(gè)空的列表
	List<Integer> list1 = new ArrayList<>();
	// 構(gòu)造一個(gè)具有10個(gè)容量的列表
	List<Integer> list2 = new ArrayList<>(10);
	list2.add(1);
	list2.add(2);
	list2.add(3);
	// list2.add("hello"); // 編譯失敗，List<Integer>已經(jīng)限定了，list2中只能存儲(chǔ)整形元素
	// list3構(gòu)造好之后，與list中的元素一致
	ArrayList<Integer> list3 = new ArrayList<>(list2);
	// 避免省略類型，否則：任意類型的元素都可以存放，使用時(shí)將是一場(chǎng)災(zāi)難
	List list4 = new ArrayList();
	list4.add("111");
	list4.add(100);
}

public static void main(String[] args) {
	List<String> list = new ArrayList<>();
	list.add("JavaSE");
	list.add("JavaWeb");
	list.add("JavaEE");
	list.add("JVM");
	list.add("測(cè)試課程");
	System.out.println(list);
	// 獲取list中有效元素個(gè)數(shù)
	System.out.println(list.size());
	// 獲取和設(shè)置index位置上的元素，注意index必須介于[0, size)間
	System.out.println(list.get(1));
	list.set(1, "JavaWEB");
	System.out.println(list.get(1));
	// 在list的index位置插入指定元素，index及后續(xù)的元素統(tǒng)一往后搬移一個(gè)位置
	list.add(1, "Java數(shù)據(jù)結(jié)構(gòu)");
	System.out.println(list);
	// 刪除指定元素，找到了就刪除，該元素之后的元素統(tǒng)一往前搬移一個(gè)位置
	list.remove("JVM");
	System.out.println(list);
	// 刪除list中index位置上的元素，注意index不要超過(guò)list中有效元素個(gè)數(shù),否則會(huì)拋出下標(biāo)越界異常
	list.remove(list.size()-1);
	System.out.println(list);

public static void main(String[] args) {
	List<Integer> list = new ArrayList<>();
	list.add(1);
	list.add(2);
	list.add(3);
	list.add(4);
	list.add(5);
	// 使用下標(biāo)+for遍歷
	for (int i = 0; i < list.size(); i++) {
		System.out.print(list.get(i) + " ");
	} 
	System.out.println();
	// 借助foreach遍歷
	for (Integer integer : list) {
		System.out.print(integer + " ");
	} 
	System.out.println();
	Iterator<Integer> it = list.listIterator();
	while(it.hasNext()){
	System.out.print(it.next() + " ");
	} 
	System.out.println();
}

Object[] elementData; // 存放元素的空間
private static final Object[] DEFAULTCAPACITY_EMPTY_ELEMENTDATA = {}; // 默認(rèn)空間
private static final int DEFAULT_CAPACITY = 10; // 默認(rèn)容量大小
public boolean add(E e) {
	ensureCapacityInternal(size + 1); // Increments modCount!!
	elementData[size++] = e;
	return true;
}
private void ensureCapacityInternal(int minCapacity) {
	ensureExplicitCapacity(calculateCapacity(elementData, minCapacity));
}
private static int calculateCapacity(Object[] elementData, int minCapacity) {
	if (elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA) {
		return Math.max(DEFAULT_CAPACITY, minCapacity);
	} 
	return minCapacity;
}
private void ensureExplicitCapacity(int minCapacity) {
	modCount++;
	// overflow-conscious code
	if (minCapacity - elementData.length > 0)
		grow(minCapacity);
	}
	private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
	private void grow(int minCapacity) {
	// 獲取舊空間大小
	int oldCapacity = elementData.length;
	// 預(yù)計(jì)按照1.5倍方式擴(kuò)容
	int newCapacity = oldCapacity + (oldCapacity >> 1);
	// 如果用戶需要擴(kuò)容大小 超過(guò) 原空間1.5倍，按照用戶所需大小擴(kuò)容
	if (newCapacity - minCapacity < 0)
	newCapacity = minCapacity;
	// 如果需要擴(kuò)容大小超過(guò)MAX_ARRAY_SIZE，重新計(jì)算容量大小
	if (newCapacity - MAX_ARRAY_SIZE > 0)
	newCapacity = hugeCapacity(minCapacity);
	// 調(diào)用copyOf擴(kuò)容
	elementData = Arrays.copyOf(elementData, newCapacity);
}
private static int hugeCapacity(int minCapacity) {
	// 如果minCapacity小于0，拋出OutOfMemoryError異常
	if (minCapacity < 0)
	throw new OutOfMemoryError();
	return (minCapacity > MAX_ARRAY_SIZE) ? Integer.MAX_VALUE : MAX_ARRAY_SIZE;
}

public class Card {
	public int rank; // 牌面值
	public String suit; // 花色
	@Override
	public String toString() {
		return String.format("[%s %d]", suit, rank);
	}
}

import java.util.List;
import java.util.ArrayList;
import java.util.Random;
public class CardDemo {
	public static final String[] SUITS = {"?", "?", "?", "?"};
	// 買一副牌
	private static List<Card> buyDeck() {
		List<Card> deck = new ArrayList<>(52);
		for (int i = 0; i < 4; i++) {
			for (int j = 1; j <= 13; j++) {
				String suit = SUITS[i];
				int rank = j;
				Card card = new Card();
				card.rank = rank;
				card.suit = suit;
				deck.add(card);
			}
		} 
		return deck;
	}
	private static void swap(List<Card> deck, int i, int j) {
		Card t = deck.get(i);
		deck.set(i, deck.get(j));
		deck.set(j, t);
	}
	private static void shuffle(List<Card> deck) {
		Random random = new Random(20190905);
		for (int i = deck.size() - 1; i > 0; i--) {
			int r = random.nextInt(i);
			swap(deck, i, r);
		}
	}
	public static void main(String[] args) {
		List<Card> deck = buyDeck();
		System.out.println("剛買回來(lái)的牌:");
		System.out.println(deck);
		shuffle(deck);
		System.out.println("洗過(guò)的牌:");
		System.out.println(deck);
		// 三個(gè)人，每個(gè)人輪流抓 5 張牌
		List<List<Card>> hands = new ArrayList<>();
		hands.add(new ArrayList<>());
		hands.add(new ArrayList<>());
		hands.add(new ArrayList<>());
		for (int i = 0; i < 5; i++) {
			for (int j = 0; j < 3; j++) {
				hands.get(j).add(deck.remove(0));
			}
		}
 		System.out.println("剩余的牌:");
		System.out.println(deck);
		System.out.println("A 手中的牌:");
		System.out.println(hands.get(0));
		System.out.println("B 手中的牌:");
		System.out.println(hands.get(1));
		System.out.println("C 手中的牌:");
		System.out.println(hands.get(2));
	}
}