Java-ThreadLocal的简单例子

内容：ThreadLocal：允许我们创建只能被同一个线程读写的变量，例如Web应用中将变量从前端到后台，并且需要在这次请求的线程中始终可以随时获取到。内部实现是通过一个ThreadLocalMap这个Map结构来实现的，将线程对象作为Key，变量副本作为Value。

public class TestThreadLocal {

	public static class MyRunnable1 implements Runnable {

		private ThreadLocal<Integer> threadlocal = new ThreadLocal<Integer>();

		@Override
		public void run() {
			threadlocal.set(new Random().nextInt(10));
			try {
				Thread.sleep(2000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println(Thread.currentThread() + " : " + threadlocal.get());
		}
	}

	public static void main(String[] args) {
		System.out.println("start");
		MyRunnable1 runnable = new MyRunnable1();
		Thread thread1 = new Thread(runnable);
		Thread thread2 = new Thread(runnable);
		thread1.start();
		thread2.start();
	}
}