java多线程的三种创建方式

最新推荐文章于 2024-11-18 20:17:55 发布

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最新推荐文章于 2024-11-18 20:17:55 发布

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分类专栏： Java基础文章标签：多线程

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本文详细介绍了Java中创建多线程的三种常见方法：继承Thread类、实现Runnable接口和实现Callable接口。通过实例演示了每种方法的具体应用，包括线程同步、线程间通信及如何获取线程返回值。

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java多线程的三种创建方式

第一种方式，继承Thread类，重写run方法，这里我模拟了一个买票的系统，四个窗口同时开始卖票

/**
 * 第一种方式，继承Thread类，重写run方法
 * 
 * @author admin
 *
 */
public class MyThread extends Thread {
	private static int num = 100; // 共享变量(基本数据类型的数据)，不能当对象锁---因为它不是对象
	private static Object obj = new Object();// 可以新建一个与基本数据类型的共享变量平行的对象，来替代它当作锁
	private String name = null;

	public MyThread(String name) {
		this.name = name;
	}

	@Override
	public void run() {
		while (true) {
			synchronized (obj) {// ※静态变量的对象锁是不能用this来代替的
				if (num > 0) {
					System.out.println(name + ":" + num);
					num--;//卖出去了一张，减去一张
					try {
						Thread.sleep(50);//睡眠0.02秒
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				} else {
					break;
				}
			}
		}
	}
}

第一种方法测试类

/**
 * 测试第一种方式
 * 
 * @author admin
 *
 */
public class MyThreadTest {

	public static void main(String[] args) {
		// 开四个窗口(new线程)，让它们都开始卖票(启动线程)
		Thread t1 = new MyThread("窗口1");
		Thread t2 = new MyThread("窗口2");
		Thread t3 = new MyThread("窗口3");
		Thread t4 = new MyThread("窗口4");
		t1.start();
		t2.start();
		t3.start();
		t4.start();
	}
}

控制台输出

窗口1:100
窗口1:99
窗口1:98
窗口1:97
窗口1:96
窗口1:95
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窗口1:93
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窗口1:67
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窗口1:65
窗口1:64
窗口1:63
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窗口1:61
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窗口1:49
窗口1:48
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窗口1:43
窗口1:42
窗口4:41
窗口4:40
窗口4:39
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窗口4:37
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窗口4:27
窗口4:26
窗口4:25
窗口2:24
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窗口2:11
窗口2:10
窗口2:9
窗口2:8
窗口2:7
窗口2:6
窗口2:5
窗口2:4
窗口2:3
窗口2:2
窗口2:1

第二种方式，实现runnable接口，重写run方法。这种方法跟第一种类似，因为Thread类实现的就是runnable接口

/**
 * 第二种方式，实现runnable接口，重写run方法
 * 
 * @author admin
 *
 */
public class MyRunnable implements Runnable {
	private static int num = 100;// 共享变量(基本数据类型的数据)，不能当对象锁---因为它不是对象
	private static Object obj = new Object();// 可以新建一个与基本数据类型的共享变量平行的对象，来替代它当作锁

	@Override
	public void run() {
		while (num > 0) {
			synchronized (obj) {
				if (num > 0) {
					System.out.println(Thread.currentThread().getName() + "---" + num);
					num--;//卖出去了一张，减去一张
					try {
						Thread.sleep(50);//睡眠0.05秒
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			}
		}
	}

}

第二种方式测试

/**
 * 测试第二种方式
 * 
 * @author admin
 *
 */
public class MyRunnableTest {
	public static void main(String[] args) {
		MyRunnable myRunnable = new MyRunnable();//创建runnable对象
		Thread thread1 = new Thread(myRunnable);//runnable对象作为Thread对象的target创建新的线程
		Thread thread2 = new Thread(myRunnable);
		Thread thread3 = new Thread(myRunnable);
		thread1.start();
		thread2.start();
		thread3.start();
	}
}

控制台

Thread-0---100
Thread-0---99
Thread-0---98
Thread-0---97
Thread-0---96
Thread-0---95
Thread-0---94
Thread-0---93
Thread-0---92
Thread-0---91
Thread-0---90
Thread-0---89
Thread-0---88
Thread-0---87
Thread-1---86
Thread-1---85
Thread-1---84
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Thread-1---80
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Thread-2---66
Thread-2---65
Thread-2---64
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Thread-2---31
Thread-2---30
Thread-2---29
Thread-2---28
Thread-1---27
Thread-1---26
Thread-1---25
Thread-1---24
Thread-1---23
Thread-1---22
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Thread-1---8
Thread-1---7
Thread-1---6
Thread-1---5
Thread-1---4
Thread-1---3
Thread-1---2
Thread-1---1

第三种方式，实现callable接口，重写call方法，这种方法可以获取线程的返回值

/**
 * 第三种方式，实现callable接口，重写call方法
 * 
 * @author admin
 *
 */
public class MyCallable implements Callable<Integer> {
	private static int i = 0;

	@Override
	public Integer call() throws Exception {
		int sum = 0;
		for (; i < 100; i++) {
			System.out.println(Thread.currentThread().getName() + " " + i);
			sum += i;
		}
		return sum;
	}

}

第三种方式测试

/**
 * 测试第三种方式
 * 
 * @author admin
 *
 */
public class MyCallableTest {
	public static void main(String[] args) {
		Callable<Integer> myCallable = new MyCallable(); // 创建MyCallable对象
		FutureTask<Integer> ft = new FutureTask<Integer>(myCallable); // 使用FutureTask来包装MyCallable对象
		Thread thread = new Thread(ft); // FutureTask对象作为Thread对象的target创建新的线程
		thread.start(); // 线程进入到就绪状态
		try {
			int sum = ft.get(); // 用FutureTask对象的get()方法取得新创建的新线程中的call()方法返回的结果
			System.out.println("sum = " + sum);
		} catch (InterruptedException e) {
			e.printStackTrace();
		} catch (ExecutionException e) {
			e.printStackTrace();
		}

	}
}

控制台

Thread-0 0
Thread-0 1
Thread-0 2
Thread-0 3
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sum = 4950

个人写的小Demo，如有不足还请各路大神指教