import java.util.*;
import java.util.concurrent.*;

/**
 * JVM垃圾回收器選型與調(diào)優(yōu) 示例代碼
 */
public class Demo {

    public static void main(String[] args) throws Exception {
        // 初始化核心組件
        System.out.println("開始演示：JVM垃圾回收器選型與調(diào)優(yōu)");

        // 核心業(yè)務(wù)邏輯
        List<String> dataList = new ArrayList<>();
        dataList.add("數(shù)據(jù)項(xiàng)一");
        dataList.add("數(shù)據(jù)項(xiàng)二");
        dataList.add("數(shù)據(jù)項(xiàng)三");

        // 使用Stream處理數(shù)據(jù)
        dataList.stream()
                .filter(item -> item.startsWith("數(shù)據(jù)"))
                .forEach(item -> System.out.println("處理：" + item));

        System.out.println("演示完成");
    }
}

import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class AdvancedService {

    @Transactional(rollbackFor = Exception.class)
    public void processData(List<String> items) {
        // 使用CompletableFuture實(shí)現(xiàn)異步處理
        CompletableFuture<Void> future = CompletableFuture.runAsync(() -> {
            items.forEach(item -> {
                // 處理每個(gè)數(shù)據(jù)項(xiàng)
                handleItem(item);
            });
        });

        try {
            future.get(30, TimeUnit.SECONDS);
        } catch (Exception e) {
            throw new RuntimeException("數(shù)據(jù)處理失敗", e);
        }
    }

    private void handleItem(String item) {
        System.out.println("處理數(shù)據(jù)：" + item);
    }
}

// 自定義線程池，避免使用默認(rèn)配置
ThreadPoolExecutor executor = new ThreadPoolExecutor(
    Runtime.getRuntime().availableProcessors(),      // 核心線程數(shù)
    Runtime.getRuntime().availableProcessors() * 2,  // 最大線程數(shù)
    60L, TimeUnit.SECONDS,                           // 空閑線程存活時(shí)間
    new LinkedBlockingQueue<>(1000),                 // 任務(wù)隊(duì)列容量
    new ThreadPoolExecutor.CallerRunsPolicy()        // 拒絕策略
);