java 多线程常用java.util.concurrent

最新推荐文章于 2025-11-27 10:55:11 发布

最新推荐文章于 2025-11-27 10:55:11 发布 · 105 阅读

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本文通过三个示例探讨了Java中线程与并发的具体实现方式，包括不使用ThreadLocal时的线程间变量共享问题、利用ThreadLocal解决线程安全问题，以及ArrayBlockingQueue和Semaphore在并发控制中的应用。

package com.pateo.api; public class TestWithNoThreadLocal { public static int a = 0; public static void main(String[] args) { MyThread myThread = new MyThread(); myThread.start(); MyThread myThread2 = new MyThread(); myThread2.start(); } public static class MyThread extends Thread { public void run() { for (int i = 0; i < 5; i++) { a = a + 1; System.out.println(Thread.currentThread().getName() + ":" + a); } } } } package com.pateo.api; import com.pateo.api.TestWithNoThreadLocal.MyThread; public class TestThreadLocal { private static ThreadLocal<Integer> a = new ThreadLocal<Integer>() { public Integer initialValue() { // 初始化，默认是返回 null return 0; } }; public static void main(String args[]) { MyThread my = new MyThread(); my.start(); MyThread myThread2 = new MyThread(); myThread2.start(); } public static class MyThread extends Thread { public void run() { for (int i = 0; i < 5; i++) { a.set(a.get() + 1); System.out.println(Thread.currentThread().getName() + ":" + a.get()); } } } }

import java.util.concurrent.ArrayBlockingQueue; public class TestArrayBlockQueue { private ArrayBlockingQueue<Integer> mQueue = new ArrayBlockingQueue<Integer>(5); private final class EventThread extends Thread { public EventThread(){ super("EventThread"); } public void run(){ while(true){ try{ mQueue.take(); }catch(InterruptedException ie) { } System.out.println("---------------------------------------"); } } } private void add() throws InterruptedException{ mQueue.put(1); } public void play() throws InterruptedException{ EventThread mEventThread = new EventThread(); mEventThread.start(); Thread.sleep(3000); } public static void main(String[] args) throws InterruptedException { TestArrayBlockQueue tab = new TestArrayBlockQueue(); tab.play(); //tab.add(); } }

package com.pateo.api; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.Semaphore;public class TestSemaphore {public static void main(String[] args) { ExecutorService exec = Executors.newCachedThreadPool(); final Semaphore semp = new Semaphore(2); for (int index = 0; index < 10; index++) { final int NO = index;Runnable runable = new Runnable() { public void run() { try { semp.acquire(); System.out.println(Thread.currentThread().getName());Thread.sleep((long) ( 10000)); semp.release(); } catch (InterruptedException e) {}} }; exec.execute(runable); } exec.shutdown();} }