Java 多线程--ThreadLocal Timer ExecutorService

ThreadLocal

/**

 * ThreadLocal:每个线程自身的存储本地、局部区域

 * @author xzlf

 *

 */

public class ThreadLocalTest01 {

//	private static ThreadLocal<Integer> threadLocal = new ThreadLocal<Integer>();

	// 更改初始化值

	/*private static ThreadLocal<Integer> threadLocal = new ThreadLocal<Integer>() {

		protected Integer initialValue() {

			return 100;};

	};*/

	private static ThreadLocal<Integer> threadLocal = new ThreadLocal<Integer>().withInitial(()->50);

	public static void main(String[] args) {

		// 获取

		System.out.println(Thread.currentThread().getName() +"-->" + threadLocal.get());

		// 设置

		threadLocal.set(200);

		System.out.println(Thread.currentThread().getName() +"-->" + threadLocal.get());

	}

}

**

 * ThreadLocal:每个线程自身的数据，更改不会影响其他线程

 * @author xzlf

 *

 */

public class TheadLocalTest02 {

	private static ThreadLocal<Integer> threadLocal = new ThreadLocal<Integer>().withInitial(()->1);

	public static void main(String[] args) {

		for(int i=0; i<5; i++) {

			new Thread(new MyRun()).start();

		}

	}

	public static class MyRun implements Runnable{

		@Override

		public void run() {

			int left = threadLocal.get();

			System.out.println(Thread.currentThread().getName() + "得到了-->" + left);

			threadLocal.set(left - 1);

			System.out.println(Thread.currentThread().getName() + "还剩下-->" + threadLocal.get());

		}

	}

}

/**

 * ThreadLocal:分析上下文 环境  起点

 * 1、构造器: 哪里调用 就属于哪里 找线程体

 * 2、run方法:本线程自身的

 * @author xzlf

 *

 */

public class TheadLocalTest03 {

	private static ThreadLocal<Integer> threadLocal = new ThreadLocal<Integer>() {

		protected Integer initialValue() {

			return 100;

		};

	};

	public static void main(String[] args) {

		new Thread(new MyRun()).start();

		new Thread(new MyRun()).start();

	}

	static class MyRun implements Runnable{

		public MyRun() {

			threadLocal.set(200);

			System.out.println(Thread.currentThread().getName() + "-->" + threadLocal.get());

		}

		@Override

		public void run() {

			System.out.println(Thread.currentThread().getName() + "-->" + threadLocal.get());

		}

	}

}

运行：



/**

 * InheritableThreadLocal:继承环境上下文的数据，拷贝一份给子线程

 *

 * @author xzlf

 *

 */

public class TheadLocalTest04 {

	private static ThreadLocal<Integer> threadLocal = new InheritableThreadLocal<Integer>();

	public static void main(String[] args) {

		threadLocal.set(2);

		System.out.println(Thread.currentThread().getName()+"-->"+threadLocal.get());

		new Thread(()-> {

			System.out.println(Thread.currentThread().getName() + "-->" + threadLocal.get());

			threadLocal.set(100);

			System.out.println(Thread.currentThread().getName() + "-->" + threadLocal.get());

		}).start();

	}

}

运行：

ExcutorService

线程池

public class TestFutrueTask {

	public static void main(String[] args) throws InterruptedException, ExecutionException {

		// 创建任务

		MyCall call = new MyCall();

		// 交给任务管理器

		FutureTask<String> task = new FutureTask<String>(call);

		// 创建代理类并启动线程

		new Thread(task).start();

		System.out.println("获取结果-->" + task.get());

		System.out.println("任务是否执行完成-->" + task.isDone());

	}

}

线程池执行带返回值的callable时需要加入到集合中，避免get() 等待结果是阻塞

package com.xzlf.testThread;

import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.Callable;

import java.util.concurrent.ExecutionException;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

import java.util.concurrent.FutureTask;

public class TestPool2 {

	public static void main(String[] args) throws Exception, Exception {

		// 创建一个线程池，线程池中只有一个线程对象

//		ExecutorService pool = Executors.newSingleThreadExecutor();

		// 创建一个线程池，线程池中数量固定

		ExecutorService pool = Executors.newFixedThreadPool(10);

		// 创建一个线程池，线程池中数量可以动态改变

//		ExecutorService pool = Executors.newCachedThreadPool();

		List<Future<Integer>> list = new ArrayList<Future<Integer>>();

		/**使用线程池执行大量的Callable任务*/

		for (int i = 0; i < 20; i++) {

			Callable<Integer> command = new Callable<Integer>() {

				@Override

				public Integer call() throws Exception {

					Thread.sleep(2000);

					return (int) (Math.random()*10);

				}

			};

			// 将任务交给线程池

			FutureTask<Integer> task =(FutureTask<Integer>) pool.submit(command);

			list.add(task);

//			pool.execute(task);

//			System.out.println(task.get());

		}

		System.out.println("ok?");

		for (Future<Integer> f : list) {

			System.out.println(f.get());

		}

		System.out.println("ok!");

		pool.shutdown();

	}

}

运行：

Timer

package com.xzlf.testThread;

import java.text.DateFormat;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Timer;

import java.util.TimerTask;

public class TestTimer {

	public static void main(String[] args) throws InterruptedException {

		// 创建Timer对象

		Timer timer = new Timer();

		// 创建任务对象

		TimerTask task = new Clock();

		// 调用schedule()方法执行任务

		timer.schedule(task, new Date(System.currentTimeMillis() + 2000), 1000);

		Thread.sleep(5000);

		timer.cancel();

	}

}

/**

 * 任务

 * @author xzlf

 *

 */

class Clock extends TimerTask{

	DateFormat df = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");

	@Override

	public void run() {

		Date date = new Date();

		String dateStr = df.format(date);

		System.out.println(dateStr);

	}

}

运行：

巴特西

Java 多线程--ThreadLocal Timer ExecutorService

ThreadLocal

ExcutorService

Timer

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