线程创建

三种方式：

1.通过继承Thread 重写run方法，

public class HelloWordThread extends  Thread {
    @Override
    public void run(){
        System.out.println("hello world!!!!!!!!");
    }

    public static void main(String[] args) {
        System.out.println("开始----");
        HelloWordThread helloWordThread = new HelloWordThread();
        System.out.println("启动----");
        helloWordThread.start();
    }
}

2.通过实现runable 重写run方法

public class HelloWorldRunable implements Runnable{
    public void run() {
        System.out.println("hello world ----------");
    }

    public static void main(String[] args) {
        System.out.println("开始---");
        HelloWorldRunable helloWorldRunable = new HelloWorldRunable();
        System.out.println("启动---");
        helloWorldRunable.run();
    }
}

3.通过 实现 Callable 使用FutureTask 对象，可以传参数以及获取返回值

 

public class HelloWorldCallable implements Callable<Integer>{
    private int i ;
    public HelloWorldCallable(int i){
            this.i = i;
    }
    @Override
    public Integer call() throws Exception {
        System.out.println("参数：：i=="+i);
        return this.i;
    }

    public static void main(String[] args) {
        //FutureTask 对象
        //无参数
        FutureTask task = new FutureTask(() -> {
            int count = 0;
            for (int i = 0; i <= 100; i++) {
                count += i;
            }
            return count;
        });
        //创建线程
        Thread thread = new Thread(task);
        thread.start();
        try {
            System.out.println("无参数：：："+task.get());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }


        //带参数
        FutureTask task1 = new FutureTask(new HelloWorldCallable(100));
        Thread thread1 = new Thread(task1);
        try {
            System.out.println("带参数：：i=="+task1.get());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }


}