写在之前

深夜水文，聊聊多线程的不同实现方式吧

继承Thread实现

//继承Thread类，重写Run方法，调用start方法
public class ThreadThread extends Thread{
    @Override
    public void run() {
        System.out.println ("Thread实现");
    }

    public static void main(String[] args) {
        ThreadThread threadDemo = new ThreadThread ();
        threadDemo.start ();
    }
}

优点：代码编写简单

缺点：不能继承其他类拓展性差

实现Runnable接口

//实现Runnable接口,重写Run方法,将Runnable接口的实现类通过Thread类的构造方法传入,调用start方法
public class ThreadRunnable implements Runnable{
    @Override
    public void run() {
        System.out.println ("Runnable方式实现");
    }

    public static void main(String[] args) {
//        Thread thread = new Thread (new ThreadRunnable ());
//        thread.start ();
        //lambda实现
        Thread thread = new Thread (() -> {
            System.out.println ("Runnable方式实现");
        });
        thread.start ();
    }
}

优点：可以实现多个接口,可以再继承一个类，拓展性好

缺点：没返回值，不能直接启动

通过callable接口和FutureTask类实现

//实现callable接口,实现call方法,结合FutureTask类实现
public class ThreadTask implements Callable {
    @Override
    public Object call() throws Exception {
        System.out.println ("Callable实现");
        return "Callable";
    }

    public static void main(String[] args) {
        Thread thread = new Thread (new FutureTask<Object> (new ThreadTask ()));
        thread.start ();
    }
}

优点：有返回值，拓展性高

缺点：jdk5以后才支持,需要多个类结合实现

线程池实现

//实现Runnable接口,实现run方法，创建线程池，传入Runnable接口实现类
public class ThreadPool implements Runnable{
    @Override
    public void run() {
        System.out.println ("线程池实现");
    }

    public static void main(String[] args) {
        ExecutorService executorService = Executors.newFixedThreadPool (3);
        executorService.execute (new ThreadPool ());
        
        executorService.shutdown ();
    }
}

优点：安全 性能高

缺点：jdk5以后才支持,需要结合Runnable接口使用