java多线程四种实现方法

package com.zrun.TestThread;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class App {
	public static void main(String[] args) throws Exception, ExecutionException {
		System.out.println("主线程启动:"
				+ new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
						.format(new Date()));

		// 方式1
		// ThreadEx thread1 = new ThreadEx();
		// thread1.start();
		// Thread.sleep(2000);
		// System.out.println("主线程执行结束:"
		// + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
		// .format(new Date()));

		// 方式2
		// Thread thread2 = new Thread(new RunableEx());
		// thread2.start();
		// Thread.sleep(2000);
		// System.out.println("主线程执行结束:"
		// + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
		// .format(new Date()));

		// 方式3
		// Callable<Object> oneCallable = new Thread3<Object>();
		// FutureTask<Object> oneTask = new FutureTask<Object>(oneCallable);
		// Thread t = new Thread(oneTask);
		// t.start();
		// Thread.sleep(2000);
		// System.out.println("主线程执行结束:"
		// + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
		// .format(new Date()));
		// // 主线程执行的2秒钟之后，子线程只要再过3秒就结束了，从而得到子线程的结果；这里get方法会阻塞主线程
		// System.out.println(oneTask.get().toString());

		// 方式4
		Thread4.test();
		Thread.sleep(2000);
		System.out.println("主线程执行结束:"
				+ new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
						.format(new Date()));
	}
}

// 方式1：继承Thread类
class ThreadEx extends Thread {
	@Override
	public void run() {
		try {
			Thread.sleep(5000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		System.out.println("子线程执行结束:"
				+ new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
						.format(new Date()));
	}
}

// 方式2：实现Runnable接口
class RunableEx implements Runnable {
	public void run() {
		try {
			Thread.sleep(5000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		System.out.println("子线程执行结束:"
				+ new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
						.format(new Date()));
	}
}

// 方式3：通过Callable和FutureTask；这种方式可以拿到子线程的返回值
class Thread3<Object> implements Callable<Object> {

	@Override
	public Object call() throws Exception {
		Thread.sleep(5000);
		return (Object) ("我是子线程的返回值:" + new SimpleDateFormat(
				"yyyy-MM-dd HH:mm:ss").format(new Date()));
	}
}

// 方式4：通过线程池创建线程
class Thread4 {
	static int POOL_NUM = 5;

	public static void test() {
		ExecutorService executorService = Executors.newFixedThreadPool(5);
		for (int i = 0; i < POOL_NUM; i++) {
			RunableEx thread = new RunableEx();
			executorService.execute(thread);
		}
		// 关闭线程池
		executorService.shutdown();
	}
}