深入理解Java中的ConcurrentSkipListMap：高效并发的有序映射

import java.util.Map;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ConcurrentSkipListMapExample {

    public static void main(String[] args) throws InterruptedException {
        // 创建一个支持高并发的有序映射，用于存储商品和库存
        Map<String, Integer> inventory = new ConcurrentSkipListMap<>();

        // 初始化库存数据
        initInventory(inventory);

        // 创建一个线程池来模拟高并发环境
        ExecutorService executor = Executors.newFixedThreadPool(10);

        // 模拟并发增加库存操作
        for (int i = 0; i < 5; i++) {
            executor.submit(() -> addInventory(inventory, "商品A", 10));
            executor.submit(() -> addInventory(inventory, "商品B", 5));
            executor.submit(() -> addInventory(inventory, "商品C", 3));
        }

        // 等待所有任务执行完毕
        executor.shutdown();
        while (!executor.isTerminated()) {
            // 等待所有任务完成
        }

        // 打印库存情况
        printInventory(inventory);

        // 模拟并发查询库存操作
        executor = Executors.newFixedThreadPool(10);
        for (int i = 0; i < 10; i++) {
            executor.submit(() -> checkInventory(inventory, "商品A"));
            executor.submit(() -> checkInventory(inventory, "商品B"));
            executor.submit(() -> checkInventory(inventory, "商品C"));
        }

        // 等待所有查询任务执行完毕
        executor.shutdown();
        while (!executor.isTerminated()) {
            // 等待所有查询任务完成
        }
    }

    /**
     * 初始化库存数据
     * @param inventory 库存映射
     */
    private static void initInventory(Map<String, Integer> inventory) {
        inventory.put("商品A", 100);
        inventory.put("商品B", 50);
        inventory.put("商品C", 30);
    }

    /**
     * 增加库存
     * @param inventory 库存映射
     * @param productName 商品名称
     * @param quantity 增加的数量
     */
    private static void addInventory(Map<String, Integer> inventory, String productName, int quantity) {
        // 库存增加操作
        inventory.merge(productName, quantity, Integer::sum);
        System.out.println("为 " + productName + " 增加了 " + quantity + " 件库存，当前库存为：" + inventory.get(productName));
    }

    /**
     * 打印库存情况
     * @param inventory 库存映射
     */
    private static void printInventory(Map<String, Integer> inventory) {
        System.out.println("当前库存情况：");
        for (Map.Entry<String, Integer> entry : inventory.entrySet()) {
            System.out.println("商品名称：" + entry.getKey() + "，库存数量：" + entry.getValue());
        }
    }

    /**
     * 检查库存
     * @param inventory 库存映射
     * @param productName 商品名称
     */
    private static void checkInventory(Map<String, Integer> inventory, String productName) {
        Integer stock = inventory.get(productName);
        if (stock != null) {
            System.out.println("查询到 " + productName + " 的库存为：" + stock);
        } else {
            System.out.println("未找到商品 " + productName + " 的库存信息。");
        }
    }
}