该提交包括以下主要变更：
1. 新增了`SingletonPattern.java`，实现了购物车管理器的单例模式，用于记录商品添加到购物车的信息，并在购买结束后打印出商品清单。这是针对设计模式专题之单例模式的练习。 2. 新增了`LeetCode138.java`，实现了复制一个包含随机指针的链表。这是对链表操作和复制的练习。 3. 新增了`Proxy.java`，实现了动态代理，用于扣费20作为中介费的案例。这是对Java代理模式的实践。 4. 对`TestCacheThreadPool.java`进行了修改，添加了多个线程安全的示例代码，包括单例模式的实现、ConcurrentHashMap的使用、ReentrantLock和Condition的使用等。这是对多线程和并发编程的探索。 这次提交的代码涵盖了设计模式、链表操作、动态代理和并发编程等多个方面，展示了作者在编程领域的广泛兴趣和实践能力。
This commit is contained in:
kyriewhluo
parent
3aaee55251
commit
cd4c443077
@ -0,0 +1,93 @@
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package cn.whaifree.designPattern;
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import java.util.HashMap;
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import java.util.Scanner;
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import java.util.function.BiConsumer;
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public class SingletonPattern {
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/**
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* https://kamacoder.com/problempage.php?pid=1074
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*
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* 【设计模式专题之单例模式】1.小明的购物车
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* 题目描述
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* 小明去了一家大型商场，拿到了一个购物车，并开始购物。请你设计一个购物车管理器，记录商品添加到购物车的信息（商品名称和购买数量），并在购买结束后打印出商品清单。（在整个购物过程中，小明只有一个购物车实例存在）。
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* 输入描述
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* 输入包含若干行，每行包含两部分信息，分别是商品名称和购买数量。商品名称和购买数量之间用空格隔开。
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* 输出描述
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* 输出包含小明购物车中的所有商品及其购买数量。每行输出一种商品的信息，格式为 "商品名称 购买数量"。
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* 输入示例
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* Apple 3
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* Banana 2
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* Orange 5
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* 输出示例
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* Apple 3
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* Banana 2
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* Orange 5
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* 提示信息
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* 本道题目请使用单例设计模式：
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*
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* 使用私有静态变量来保存购物车实例。
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*
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* 使用私有构造函数防止外部直接实例化。
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*/
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static class ManagerCar{
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private HashMap<String, Integer> carHas = null;
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public ManagerCar() {
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this.carHas = new HashMap<>();
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}
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public HashMap<String, Integer> getCarHas() {
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return carHas;
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}
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private volatile static ManagerCar managerCar;
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public static ManagerCar getManagerCar() {
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if (managerCar == null) {
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synchronized (ManagerCar.class) {
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if (managerCar == null) {
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managerCar = new ManagerCar();
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}
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}
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}
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return managerCar;
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}
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}
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public static void main(String[] args) {
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Scanner scanner = new Scanner(System.in);
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HashMap<String, Integer> carHas = ManagerCar.getManagerCar().getCarHas();
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while (true) {
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String nextLine = scanner.nextLine();
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if ("stop".equals(nextLine)) {
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break;
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}
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String[] s = nextLine.split(" ");
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String obj = s[0];
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Integer num = Integer.valueOf(s[1]);
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carHas.put(obj, carHas.getOrDefault(obj, 0) + num);
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/**
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* 添加商品到购物车
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* public void addItem(String name, int quantity) {
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* items.merge(name, quantity, Integer::sum);
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*
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*/
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}
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carHas.forEach(
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(s, integer) -> System.out.println(s + " " + integer)
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);
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scanner.close();
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}
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}
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@ -0,0 +1,86 @@
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package cn.whaifree.leetCode.LinkedList;
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import org.junit.Test;
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public class LeetCode138 {
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static class Node {
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int val;
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Node next;
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Node random;
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public Node(int val) {
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this.val = val;
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this.next = null;
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this.random = null;
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}
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}
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@Test
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public void test() {
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// 1 2 3
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// 1 3
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// 2 1
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// Node node1 = new Node(1);
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// Node node2 = new Node(2);
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// Node node3 = new Node(3);
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// node1.next = node2;
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// node2.next = node3;
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// node1.random = node3;
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// node2.random = node1;
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// Node node = copyRandomList(node1);
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// System.out.println(node);
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// [[7,null],[13,0],[11,4],[10,2],[1,0]]
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Node node1 = new Node(7);
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Node node2 = new Node(13);
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Node node3 = new Node(11);
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Node node4 = new Node(10);
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Node node5 = new Node(1);
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node1.next = node2;
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node2.next = node3;
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node3.next = node4;
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node4.next = node5;
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node2.random = node1;
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node3.random = node5;
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node4.random = node3;
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node5.random = node1;
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Node node = copyRandomList(node1);
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System.out.println(node);
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}
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public Node copyRandomList(Node head) {
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Node index = head;
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while (index != null) {
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Node tmp = index.next;
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index.next = new Node(index.val);
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index.next.next = tmp;
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index = index.next.next;
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}
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index = head;
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while (index != null) {
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if (index.random != null) {
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index.next.random = index.random.next;
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}
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index = index.next.next;
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}
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Node newHead = head.next;
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index = newHead;
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Node tmpPreIndex = head;
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while (index.next != null) {
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tmpPreIndex.next = tmpPreIndex.next.next;
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tmpPreIndex = tmpPreIndex.next;
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index.next = index.next.next;
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index = index.next;
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}
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tmpPreIndex.next = null;
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return newHead;
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}
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}
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53
src/main/java/cn/whaifree/test/Proxy.java
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53
src/main/java/cn/whaifree/test/Proxy.java
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package cn.whaifree.test;
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import net.sf.cglib.proxy.Enhancer;
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import net.sf.cglib.proxy.MethodInterceptor;
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import net.sf.cglib.proxy.MethodProxy;
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import java.lang.reflect.Method;
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public class Proxy {
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public static void main(String[] args) {
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Enhancer enhancer = new Enhancer();
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enhancer.setSuperclass(Rent.class);
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enhancer.setCallback(new Agency());
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Rent o = (Rent) enhancer.create();
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System.out.println("起始的钱：" + o.money);
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o.rent();
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System.out.println("剩下的钱：" + o.money);
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}
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static class Rent{
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int money = 100;
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void rent() {
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System.out.println("租房！");
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}
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}
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static class Agency implements MethodInterceptor {
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@Override
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public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
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Rent o1 = (Rent) o;
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o1.money -= 20;
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System.out.println("扣费20为中介费");
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return methodProxy.invokeSuper(o, objects);
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//https://blog.csdn.net/z69183787/article/details/106878203
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/**
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* 调用invoke实际是调用cglib生成的子类的方法
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* 这个子类
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* method{
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* interceptor(obj.method)
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* }
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* 正确使用：
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* 将obj从其他地方传进来
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*
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*
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* 调用invokeSuper实际是调用父类的方法method
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*/
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}
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}
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}
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@ -1,11 +1,15 @@
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package cn.whaifree.test;
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import org.junit.Test;
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import java.io.ByteArrayInputStream;
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import java.io.IOException;
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import java.nio.charset.Charset;
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import java.util.concurrent.Executor;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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import java.util.concurrent.Callable;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.atomic.AtomicReference;
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import java.util.concurrent.locks.Condition;
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import java.util.concurrent.locks.ReentrantLock;
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public class TestCacheThreadPool {
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System.out.println("\n");
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}
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ConcurrentHashMap<String, String> map = new ConcurrentHashMap<>();
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map.put("1", "233");
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String compute = map.compute("1", (k, v) -> {
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return k + v;
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});
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String merge = map.merge("1", "233", (k, v) -> {
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return k + v; // 没有就value，有就+value
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});
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System.out.println(merge);
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System.out.println(compute);
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// ExecutorService executorService = Executors.newCachedThreadPool();
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// for (int i = 0; i < 10; i++) {
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// int finalI = i;
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}
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}
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@Test
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public void single() {
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for (int i = 0; i < 100; i++) {
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new Thread(new Runnable() {
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@Override
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public void run() {
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System.out.println(Thread.currentThread().getName() + " " + Single.getSingle());
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}
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}).start();
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}
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}
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static class Single {
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private static Single o = null;
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public static Single getSingle() {
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if (o == null) {
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synchronized (Single.class) {
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if (o == null) { // 防止第二个线程再创建一个
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System.out.println("创建");
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o = new Single();
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}
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}
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}
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return o;
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}
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}
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static class Singleton {
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// 不使用volatile关键字
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private static Singleton instance;
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private Singleton() {
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}
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public static Singleton getInstance() {
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if (instance == null) {
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synchronized (Singleton.class) {
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if (instance == null) {
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instance = new Singleton();
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}
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}
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}
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return instance;
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}
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public static void main(String[] args) {
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// 创建多个线程尝试获取单例实例
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for (int i = 0; i < 10; i++) {
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new Thread(() -> {
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for (int j = 0; j < 10; j++) {
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new Thread(new Runnable() {
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@Override
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public void run() {
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System.out.println(Thread.currentThread().getName() + " 获取到的实例为: " + Singleton.getInstance());
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}
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}).start();
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}
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System.out.println("-======");
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}).start();
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}
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}
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}
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static class MultiConditionDemo {
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private final ReentrantLock lock = new ReentrantLock();
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private final Condition condition1 = lock.newCondition();
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private final Condition condition2 = lock.newCondition();
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private String message = "等待消息";
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public static void main(String[] args) {
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MultiConditionDemo demo = new MultiConditionDemo();
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new Thread(() -> demo.producer()).start();
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new Thread(() -> demo.consumer()).start();
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}
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public void producer() {
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lock.lock();
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try {
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while ("等待消息".equals(message)) {
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condition1.await(); // 等待条件1
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}
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message = "这是生产者发送的消息";
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System.out.println("生产者发送消息：" + message);
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condition2.signal(); // 通知条件2上的等待线程
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} catch (InterruptedException e) {
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e.printStackTrace();
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} finally {
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lock.unlock();
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}
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}
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public void consumer() {
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lock.lock();
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try {
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while (!"这是生产者发送的消息".equals(message)) {
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condition2.await(); // 等待条件2
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}
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System.out.println("消费者接收到的消息：" + message);
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message = "等待消息";
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condition1.signal(); // 通知条件1上的等待线程
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} catch (InterruptedException e) {
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e.printStackTrace();
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} finally {
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lock.unlock();
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}
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}
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}
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static class reentrantLockDemo {
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static ReentrantLock lock = new ReentrantLock();
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static int num = 0;
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static Condition condition = lock.newCondition();
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public static void main(String[] args) {
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new Thread(new Runnable() {
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@Override
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public void run() {
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for (int i = 0; i < 100; i++) {
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lock.lock();
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while (num % 2 == 0) {
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try {
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condition.await();
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} catch (InterruptedException e) {
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throw new RuntimeException(e);
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}
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}
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System.out.println("A");
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num++;
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condition.signalAll();
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lock.unlock();
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}
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}
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}).start();
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new Thread(new Runnable() {
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@Override
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public void run() {
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for (int i = 0; i < 100; i++) {
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lock.lock();
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while (num % 2 != 0) {
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try {
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condition.await();
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} catch (InterruptedException e) {
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throw new RuntimeException(e);
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}
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}
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System.out.println("B");
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num++;
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condition.signalAll();
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lock.unlock();
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}
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}
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}).start();
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}
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}
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static class synDemo {
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static Object lock = new Object();
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// static Condition condition = lock.newCondition();
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static int num = 0;
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public static void main(String[] args) throws InterruptedException {
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new Thread(new Runnable() {
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@Override
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public void run() {
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for (int i = 0; i < 100; i++) {
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synchronized (lock) {
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while (num % 2 == 0) {
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try {
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lock.wait();
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} catch (InterruptedException e) {
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throw new RuntimeException(e);
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}
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}
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System.out.println("A");
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num++;
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lock.notify();
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}
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}
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}
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}).start();
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new Thread(new Runnable() {
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@Override
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public void run() {
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for (int i = 0; i < 100; i++) {
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synchronized (lock) {
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while (num % 2 == 1) {
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try {
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lock.wait();
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} catch (InterruptedException e) {
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throw new RuntimeException(e);
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}
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}
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System.out.println("B");
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num++;
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lock.notify();
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}
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}
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}
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}).start();
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}
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}
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}
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