Java多執行緒學習筆記（自用）

Java多執行緒

Thread類中的主要方法

1. start()：開啟執行緒
2. run()：繼承重寫run()
3. currentThread()：返回當前執行緒
4. getName()：返回執行緒名
5. setName()：設定執行緒名
6. yield()：釋放cpu執行權
7. b.join()：a執行緒阻塞並等待b執行緒執行完成
8. stop()：已過時，強制結束執行緒
9. sleep()：睡眠ms
10. isAlive()：是否存活

建立方式，jdk5.0前兩種，jdk5.0後兩種

1. 繼承Thread類
2. 實現Runnable介面
3. 實現Callable介面
4. 執行緒池

1.繼承Thread的方法

/**
 * @author Microdust
 * @create 2020/11/24-19:40
 */
class MyThread extends Thread{
    @Override
    public void run() {
        for (int i = 0; i <= 100; i++) {
            if (i % 2 == 0) {
                System.out.println(Thread.currentThread().getName() +
                        ":" + i);
            }
        }
    }
}
public class MyThreadTest1 {
    public static void main(String[] args) {
        MyThread t1 = new MyThread();
	t1.setName("thread1");
        t1.start();
    }

}

2.實現Runnable介面的方法

class MyThread2 implements Runnable{
    @Override
    public void run() {
        for (int i = 0; i <= 100; i++) {
            if (i % 2 == 0) {
                System.out.println(Thread.currentThread().getName() +
                        ":" + i);
            }
        }
    }
}
public class MyThreadTest2 {
    public static void main(String[] args) {
        MyThread2 m1 = new MyThread2();
        Thread t1 = new Thread(m1);
        t1.setName("thread1");
        t1.start();
    }

}

3.實現Callable介面的方法

class MyThread3 implements Callable {
    @Override
    public Object call() throws Exception {
        int sum = 0;
        for (int i = 0; i <= 100; i++) {
            if (i % 2 == 0) {
                sum += i;
                System.out.println(Thread.currentThread().getName() +
                        ":" + i);
            }
        }
        return sum;
    }
}
public class MyThreadTest3 {
    public static void main(String[] args) {
        FutureTask futureTask = new FutureTask(new MyThread3());//Runnable
        Thread t1 = new Thread(futureTask);
        t1.setName("thread1");
        t1.start();

        try {
            System.out.println(futureTask.get());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }

}

4.使用執行緒池建立執行緒

class MyThread4 implements Runnable{
    @Override
    public void run() {
        for (int i = 0; i <= 100; i++) {
            if (i % 2 != 0) {
                System.out.println(Thread.currentThread().getName() +
                        ":" + i);
            }
        }
    }
}
class MyThread5 implements Callable{
    @Override
    public Object call() throws Exception {
        int sum = 0;
        for (int i = 0; i <= 100; i++) {
            if (i % 2 == 0) {
                sum += i;
                System.out.println(Thread.currentThread().getName() +
                        ":" + i);
            }
        }
        return sum;
    }
}
public class MyThreadTest4 {
    public static void main(String[] args) {
        ExecutorService service = Executors.newFixedThreadPool(10);
//        ThreadPoolExecutor service1 = (ThreadPoolExecutor)service;
//        service1.setCorePoolSize(10);
//        service1.setKeepAliveTime(...);
        service.execute(new MyThread4());
        Future future = service.submit(new MyThread5());//返回Future類物件
        try {
            System.out.println(future.get());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
        service.shutdown();
    }


}

執行緒同步方法：

1. Synchronized （同步程式碼塊，同步方法）同步監視器多個執行緒共用一個（共享資料時）
2. Lock介面的實現類ReentrantLock物件的方法,lock.lock()、lock.unlock()

執行緒通訊方法：

1. wait() 阻塞
2. notify()/notifyAll() 喚醒