Java中创建线程池的几种方式以及区别

//创建一个固定大小的线程池，模拟提交 10 个任务到线程池。
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class FixedThreadPoolExample {
    public static void main(String[] args) {
        ExecutorService fixedThreadPool = Executors.newFixedThreadPool(3); // 创建一个具有3个线程的固定线程池
        
        for (int i = 1; i <= 10; i++) {
            final int task = i;
            fixedThreadPool.execute(() -> {
                System.out.println("执行任务 " + task + "，线程：" + Thread.currentThread().getName());
            });
        }
        
        fixedThreadPool.shutdown();
    }
}

//创建一个缓存线程池来处理任务，模拟并发执行 10 个任务

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

public class CachedThreadPoolExample {
    public static void main(String[] args) {
        ExecutorService cachedThreadPool = Executors.newCachedThreadPool();
        
        for (int i = 1; i <= 10; i++) {
            final int task = i;
            cachedThreadPool.execute(() -> {
                System.out.println("执行任务 " + task + "，线程：" + Thread.currentThread().getName());
            });
        }
        
        cachedThreadPool.shutdown();
    }
}

//创建一个单线程线程池，顺序执行多个任务。
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class SingleThreadExecutorExample {
    public static void main(String[] args) {
        ExecutorService singleThreadExecutor = Executors.newSingleThreadExecutor();
        
        for (int i = 1; i <= 5; i++) {
            final int task = i;
            singleThreadExecutor.execute(() -> {
                System.out.println("执行任务 " + task + "，线程：" + Thread.currentThread().getName());
            });
        }
        
        singleThreadExecutor.shutdown();
    }
}

//创建一个支持定时和周期性执行任务的线程池，示例任务每隔 2 秒执行一次，共执行 3 次。
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class ScheduledThreadPoolExample {
    public static void main(String[] args) {
        ScheduledExecutorService scheduledThreadPool = Executors.newScheduledThreadPool(2); // 创建一个有2个线程的定时线程池
        
        scheduledThreadPool.scheduleAtFixedRate(() -> {
            System.out.println("定时任务执行，线程：" + Thread.currentThread().getName());
        }, 0, 2, TimeUnit.SECONDS); // 0秒延迟后开始，每隔2秒执行一次任务
        
        // 程序运行5秒后关闭线程池
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        
        scheduledThreadPool.shutdown();
    }
}

//创建一个基于任务分解的线程池来并行执行多个任务，适合处理需要拆分的小任务。
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

public class WorkStealingPoolExample {
    public static void main(String[] args) throws InterruptedException {
        ExecutorService workStealingPool = Executors.newWorkStealingPool(); // 创建默认线程数为CPU核心数的工作窃取线程池
        
        for (int i = 1; i <= 8; i++) {
            final int task = i;
            workStealingPool.submit(() -> {
                System.out.println("执行任务 " + task + "，线程：" + Thread.currentThread().getName());
                try {
                    TimeUnit.SECONDS.sleep(1);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            });
        }
        
        // 让主线程等待子任务执行完成
        workStealingPool.awaitTermination(3, TimeUnit.SECONDS);
        workStealingPool.shutdown();
    }
}