Java线程的生命周期与异步任务管理：从手动创建到线程池优化

public Advert saveAdvert(Advert advert) {
    Advert advertToSave = advertRepository.save(advert);

    new Thread(() -> {
        try {
            populateAdvertSearch(advertToSave);
        } catch (ParseException | OfficeNotFoundException | OfficePropertyNotFoundException e) {
            e.printStackTrace();
        }
    }).start(); // 每次调用saveAdvert都会创建一个新的Thread实例
    return advertToSave;
}

import java.text.ParseException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.springframework.stereotype.Service;

@Service
public class AdvertService {

    private final AdvertRepository advertRepository;
    // 推荐使用一个固定大小的线程池来处理后台任务
    // 根据实际需求选择合适的线程池类型，例如：
    // Executors.newFixedThreadPool(5) - 固定数量的线程池
    // Executors.newCachedThreadPool() - 按需创建线程的缓存线程池
    // Executors.newSingleThreadExecutor() - 单一工作线程的线程池
    private final ExecutorService executorService = Executors.newFixedThreadPool(5); // 例如，创建5个线程的线程池

    public AdvertService(AdvertRepository advertRepository) {
        this.advertRepository = advertRepository;
    }

    public Advert saveAdvert(Advert advert) {
        Advert advertToSave = advertRepository.save(advert);

        // 使用ExecutorService提交异步任务
        executorService.execute(() -> {
            try {
                populateAdvertSearch(advertToSave);
            } catch (ParseException | OfficeNotFoundException | OfficePropertyNotFoundException e) {
                // 异步任务中的异常处理至关重要，避免异常被吞噬或导致线程池中的线程异常终止
                System.err.println("Error populating advert search for advert ID: " + advertToSave.getId());
                e.printStackTrace();
            }
        });
        return advertToSave;
    }

    // 假设populateAdvertSearch是一个耗时的方法
    private void populateAdvertSearch(Advert advert) throws ParseException, OfficeNotFoundException, OfficePropertyNotFoundException {
        // 模拟耗时操作
        System.out.println("Populating advert search for advert ID: " + advert.getId() + " by thread: " + Thread.currentThread().getName());
        try {
            Thread.sleep(2000); // 模拟2秒处理时间
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt(); // 重新设置中断状态
            System.err.println("Populate advert search interrupted.");
        }
        // 实际的业务逻辑
    }

    // 在应用程序关闭时，需要优雅地关闭ExecutorService以释放资源
    // 在Spring Boot应用中，可以通过@PreDestroy注解或实现DisposableBean接口来处理
    // 例如，在Spring Bean的生命周期结束时调用此方法
    public void shutdownExecutor() {
        executorService.shutdown(); // 启动有序关闭，不再接受新任务，但会执行已提交的任务
        try {
            // 等待所有任务完成，或者超时
            if (!executorService.awaitTermination(60, java.util.concurrent.TimeUnit.SECONDS)) {
                executorService.shutdownNow(); // 立即关闭，尝试取消正在执行的任务并清空任务队列
            }
        } catch (InterruptedException e) {
            executorService.shutdownNow(); // 捕获中断异常时也应立即关闭