如何在并发场景下，使用非线程安全的集合类

1、背景介绍

       ArrayList、HashSet、HashMap等非线程安全类，如何在并发场景下使用呢？

2、Collections

       Collections工具类，提供了几个方法，可以将非线程安全的类对象，转换为线程安全的类对象。具体方法为：synchronizedList、synchronizedSet、synchronizedMap。

3、实例代码

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TestSingleton {
	
	boolean lock ;
	
	public boolean isLock() {
		return lock;
	}

	public void setLock(boolean lock) {
		this.lock = lock;
	}
	
	public static void main(String[] args) throws InterruptedException {
		final Set instanceSet = Collections.synchronizedSet(new HashSet());
		final TestSingleton lock = new TestSingleton();
		lock.setLock(true);
		ExecutorService executorService = Executors.newCachedThreadPool();
		for (int i = 0; i < 100; i++) {
			executorService.execute(new Runnable() {
				
				public void run() {
					while (true) {
						if (!lock.isLock()) {
							Singleton singleton = Singleton.getInstance();
							instanceSet.add(singleton.toString());
							break;
						}
					}
				}
			});
		}
		Thread.sleep(5000);
		lock.setLock(false);
		Thread.sleep(5000);
		System.out.println("------并发情况下我们取到的实例------");
		for (String instance : instanceSet) {
			System.out.println(instance);
		}
		executorService.shutdown();
	}
}

说明，实例代码转自：http://blog.csdn.net/zuoxiaolong8810/article/details/9005611