创建线程的4种方式

一、继承Thread类

public class Main {public static void main(String[] args) {
//        // 1.创建Thread子类对象
//        ThreadDemo threadDemo = new ThreadDemo();
//        // 2.启动线程
//        threadDemo.start();// 使用内部类方式new Thread() {@Overridepublic void run() {System.out.println("继承Thread来创建线程:" + Thread.currentThread().getName());}}.start();}static class ThreadDemo extends Thread {@Overridepublic void run() {System.out.println("继承Thread来创建线程:" + Thread.currentThread().getName());}}
}

二、实现Runnable接口

public class Main {public static void main(String[] args) {
//        // 1.创建Runnable实现类对象
//        ThreadDemo threadDemo = new ThreadDemo();
//        // 2.创建Thread对象
//        Thread thread = new Thread(threadDemo);
//        // 3.启动线程
//        thread.start();// 使用内部类方式new Thread(new Runnable() {public void run() {System.out.println("实现Runnable来创建线程:" + Thread.currentThread().getName());}}).start();}static class ThreadDemo implements Runnable {public void run() {System.out.println("实现Runnable来创建线程:" + Thread.currentThread().getName());}}
}

三、实现Callable接口

public class Main {public static void main(String[] args) {// 1.创建Callable实现对象ThreadDemo threadDemo = new ThreadDemo();// 2.创建FutureTask对象FutureTask<String> futureTask = new FutureTask<String>(threadDemo);// 3.创建Thread对象Thread thread = new Thread(futureTask);// 4.启动线程thread.start();// 获取线程返回值try {String callReturn = futureTask.get(); // 会一直等待线程结束获取其返回值，如果线程被中断会抛异常System.out.println(callReturn);} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();}}static class ThreadDemo implements Callable<String> {public String call() throws Exception {return "实现Callable接口创建线程:" + Thread.currentThread().getName();}}
}

四、使用Executor框架来创建线程池

public class Main {public static void main(String[] args) {// 方式1.Executors创建单个线程池
//        ExecutorService pool = Executors.newSingleThreadExecutor();
//        pool.execute(new Runnable() {
//            public void run() {
//                System.out.println("线程池创建线程:" + Thread.currentThread().getName());
//            }
//        });
//        pool.shutdown();// 方式2.Executors创建固定数量线程池ExecutorService pool = Executors.newFixedThreadPool(5);List<Future<String>> futures = new ArrayList<Future<String>>(); // 存储结果集for(int i = 0; i < 5; i++) {Future<String> submit = pool.submit(new Callable<String>() {public String call() throws Exception {return "线程池创建线程:" + Thread.currentThread().getName();}});futures.add(submit);}System.out.println("开始获取任务结果");for(Future<String> future : futures) {try {// 使用get(long timeout, TimeUnit unit)指定获取结果超时时间System.out.println(future.get(1000, TimeUnit.SECONDS));} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();} catch (TimeoutException e) {e.printStackTrace();}}System.out.println("获取任务结果结束");// 关闭线程池pool.shutdown();}
}

执行结果：
开始获取任务结果
线程池创建线程:pool-1-thread-1
线程池创建线程:pool-1-thread-2
线程池创建线程:pool-1-thread-3
线程池创建线程:pool-1-thread-4
线程池创建线程:pool-1-thread-5
获取任务结果结束