Java并发编程(一) 线程介绍、常用方法、两阶段终止状态、线程的五种六种状态

// 构造方法的参数是给线程指定名字，推荐
Thread t1 = new Thread("t1") {//使用匿名内部类
    @Override
    // run 方法内实现了要执行的任务
    public void run() {
        log.debug("hello");
    }
};

//启动线程
t1.start();

// 创建任务对象
Runnable task2 = new Runnable() {
    @Override
    public void run() {
        log.debug("hello");
    }
};

// 参数1 是任务对象; 参数2 是线程名字，推荐
Thread t2 = new Thread(task2, "t2");
t2.start();

// 创建任务对象
Runnable task2 = () -> log.debug("hello");

// 参数1 是任务对象; 参数2 是线程名字，推荐
Thread t2 = new Thread(task2, "t2");
t2.start();

// 创建任务对象
FutureTask<Integer> task3 = new FutureTask<>(() -> {
    log.debug("hello");
    return 100;
});

// 参数1 是任务对象; 参数2 是线程名字，推荐
Thread t3 = new Thread(task3, "t3");
t3.start();

// 主线程阻塞，同步等待 task 执行完毕的结果
Integer result = task3.get();
log.debug("结果是:{}", result);

/**
 * 创建线程的方式四：使用线程池
 *
 * 好处：
 * 1.提高响应速度（减少了创建新线程的时间）
 * 2.降低资源消耗（重复利用线程池中线程，不需要每次都创建）
 * 3.便于线程管理
 *      corePoolSize：核心池的大小
 *      maximumPoolSize：最大线程数
 *      keepAliveTime：线程没有任务时最多保持多长时间后会终止
 *
 *
 * 面试题：创建多线程有几种方式？四种！
 */

class NumberThread 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 NumberThread1 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 ThreadPool {

    public static void main(String[] args) {
        //1. 提供指定线程数量的线程池
        ExecutorService service = Executors.newFixedThreadPool(10);
        ThreadPoolExecutor service1 = (ThreadPoolExecutor) service;
        //设置线程池的属性
//        System.out.println(service.getClass());
//        service1.setCorePoolSize(15);
//        service1.setKeepAliveTime();


        //2.执行指定的线程的操作。需要提供实现Runnable接口或Callable接口实现类的对象
        service.execute(new NumberThread());//适合使用于Runnable
        service.execute(new NumberThread1());//适合使用于Runnable

//        service.submit(Callable callable);//适合使用于Callable
        //3.关闭连接池
        service.shutdown();
    }
}

public class TestFrames {
    public static void main(String[] args) {
        method1(10);
    }
    public static void method1(int x) {
        int y = x + 1;
        Object m = method2();
        System.out.println(m);
    }
    public static void method2() {
		Object n = new Object();
        return n;
    }
}

public static void main(String[] args) {
    Thread thread = new Thread(){
      @Override
      public void run(){
          log.debug("我是一个新建的线程正在运行中");
          FileReader.read(fileName);
      }
    };
    thread.setName("新建线程");
    thread.start();
    log.debug("主线程");
}

thread1.setPriority(Thread.MAX_PRIORITY); //设置为优先级最高。最大为10，最小为1，默认为5

private static void test1() throws InterruptedException {
    log.debug("开始");
    Thread t1 = new Thread(() -> {
        log.debug("开始");
        sleep(1);
        log.debug("结束");
        r = 10;
    },"t1");
    t1.start();
    // t1.join(); 
    // 这里如果不加t1.join(), 此时主线程不会等待t1线程给r赋值, 主线程直接就输出r=0结束了
    // 如果加上t1.join(), 此时主线程会等待到t1线程执行完才会继续执行.(同步), 此时r=10;
    log.debug("结果为:{}", r);
    log.debug("结束");
}

static int r1 = 0;
static int r2 = 0;
public static void main(String[] args) throws InterruptedException {
    test2();
}
private static void test2() throws InterruptedException {
    Thread t1 = new Thread(() -> {
        sleep(1);
        r1 = 10;
    });
    Thread t2 = new Thread(() -> {
        sleep(2);
        r2 = 20;
    });
    long start = System.currentTimeMillis();
    t1.start();
    t2.start();
    
    t1.join();
    t2.join();
    long end = System.currentTimeMillis();
    log.debug("r1: {} r2: {} cost: {}", r1, r2, end - start);
}

static int r1 = 0;
static int r2 = 0;
public static void main(String[] args) throws InterruptedException {
    test3();
}
public static void test3() throws InterruptedException {
    Thread t1 = new Thread(() -> {
        sleep(1);
        r1 = 10;
    });
    long start = System.currentTimeMillis();
    t1.start();
    // 线程执行结束会导致 join 结束
    t1.join(1500);
    long end = System.currentTimeMillis();
    log.debug("r1: {} r2: {} cost: {}", r1, r2, end - start);
}

static int r1 = 0;
static int r2 = 0;
public static void main(String[] args) throws InterruptedException {
    test3();
}
public static void test3() throws InterruptedException {
    Thread t1 = new Thread(() -> {
        sleep(2);
        r1 = 10;
    });
    long start = System.currentTimeMillis();
    t1.start();
    // 超过时间之后会导致 join 结束，此时线程还处于 sleep 状态
    t1.join(1500);
    long end = System.currentTimeMillis();
    log.debug("r1: {} r2: {} cost: {}", r1, r2, end - start);
}

public static void main(String[] args) throws InterruptedException {
        Thread t1 = new Thread(() -> {
            System.out.println("sleep...");
            try {
                Thread.sleep(5000); // wait, join
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        });
        t1.start();
        Thread.sleep(1000);
        System.out.println("iterrupt..");
        t1.interrupt();
        System.out.println(t1.isInterrupted()); // 如果是打断sleep,wait,join的线程, 即使打断了, 标记也为false
    }
}

public static void main(String[] args) throws InterruptedException {
    Thread t1 = new Thread(() -> {
        while(true) {
            boolean interrupted = Thread.currentThread().isInterrupted();
            if(interrupted) {
                System.out.println("被打断了, 退出循环");
                break;
            }
        }
    }, "t1");
    t1.start();
    Thread.sleep(1000);
    System.out.println("interrupt");
    t1.interrupt();
    System.out.println("打断标记为: "+t1.isInterrupted());
}

public class Test7 {
	public static void main(String[] args) throws InterruptedException {
		Monitor monitor = new Monitor();
		monitor.start();
		Thread.sleep(3500);
		monitor.stop();
	}
}

class Monitor {

	Thread monitor;

	/**
	 * 启动监控器线程
	 */
	public void start() {
		//设置监控器线程，用于监控线程状态
		monitor = new Thread() {
			@Override
			public void run() {
				//开始不停的监控
				while (true) {
                    //判断当前线程是否被打断了
					if(Thread.currentThread().isInterrupted()) {
						System.out.println("处理后续任务");
                        //终止线程执行
						break;
					}
					System.out.println("监控器运行中...");
					try {
						//线程休眠
						Thread.sleep(1000);
                        log.debug("执行监控记录");
					} catch (InterruptedException e) {
						e.printStackTrace();
						//如果是在休眠的时候被打断，不会将打断标记设置为true，这时要重新设置打断标记
						Thread.currentThread().interrupt();
					}
				}
			}
		};
		monitor.start();
	}

	/**
	 * 	用于停止监控器线程
	 */
	public void stop() {
		//打断线程
		monitor.interrupt();
	}
}

private static void test3() throws InterruptedException {
    Thread t1 = new Thread(() -> {
        log.debug("park...");
        LockSupport.park();//让当前线程停下来
        log.debug("unpark...");
        log.debug("打断状态：{}", Thread.currentThread().isInterrupted());
    }, "t1");
    t1.start();
    sleep(0.5);
    t1.interrupt();
}

private static void test4() {
    Thread t1 = new Thread(() -> {
        for (int i = 0; i < 5; i++) {
            log.debug("park...");
            LockSupport.park();
            log.debug("打断状态：{}", Thread.currentThread().isInterrupted());
        }
    });
    t1.start();
    sleep(1);
    t1.interrupt();
}

log.debug("开始运行...");
Thread t1 = new Thread(() -> {
    log.debug("开始运行...");
    sleep(2);
    log.debug("运行结束...");
}, "daemon");

// 设置该线程为守护线程
t1.setDaemon(true);
t1.start();
sleep(1);
log.debug("运行结束...");

@Slf4j(topic = "c.TestState")
public class TestState {
    public static void main(String[] args) throws IOException {
        Thread t1 = new Thread("t1") {	// new 状态
            @Override
            public void run() {
                log.debug("running...");
            }
        };

        Thread t2 = new Thread("t2") {
            @Override
            public void run() {
                while(true) { // runnable 状态

                }
            }
        };
        t2.start();

        Thread t3 = new Thread("t3") {
            @Override
            public void run() {
                log.debug("running...");
            }
        };
        t3.start();

        Thread t4 = new Thread("t4") {
            @Override
            public void run() {
                synchronized (TestState.class) {
                    try {
                        Thread.sleep(1000000); // timed_waiting 显示阻塞状态
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        };
        t4.start();

        Thread t5 = new Thread("t5") {
            @Override
            public void run() {
                try {
                    t2.join(); // waiting 状态
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }  
            }
        };
        t5.start();

        Thread t6 = new Thread("t6") {
            @Override
            public void run() {
                synchronized (TestState.class) { // blocked 状态
                    try {
                        Thread.sleep(1000000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        };
        t6.start();

        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        log.debug("t1 state {}", t1.getState());
        log.debug("t2 state {}", t2.getState());
        log.debug("t3 state {}", t3.getState());
        log.debug("t4 state {}", t4.getState());
        log.debug("t5 state {}", t5.getState());
        log.debug("t6 state {}", t6.getState());
    }
}