线程与线程池，实例比较。线程池：
int count = 200000; long startTime = System.currentTimeMillis(); final List<Integer> l = new LinkedList<Integer>(); ThreadPoolExecutor tp = new ThreadPoolExecutor(1, 1, 60, TimeUnit.SECONDS, new LinkedBlockingDeque<Runnable>(count)); final Random random = new Random(); for (int i = 0; i < count; i++) { tp.execute(new Runnable() { @Override public void run() { l.add(random.nextInt()); } }); } tp.shutdown(); try { tp.awaitTermination(1, TimeUnit.DAYS); } catch (InterruptedException e) { e.PRintStackTrace(); } System.out.println(System.currentTimeMillis() - startTime); System.out.println(l.size());
输出结果：
1 1722 200000
线程：
int count = 200000; long startTime = System.currentTimeMillis(); final List<Integer> l = new LinkedList<Integer>(); final Random random = new Random(); for (int i = 0; i < count; i++) { Thread thread = new Thread(){ @Override public void run(){ l.add(random.nextInt()); } }; thread.start(); try { thread.join(); } catch (InterruptedException e) { e.printStackTrace(); } } System.out.println(System.currentTimeMillis() - startTime); System.out.println(l.size());
输出结果：
1 335562 200000
总结：差异在于线程池是复用线程的，而不使用线程池是每次都要去创建线程。线程中执行工作很简单，创建线程的开销占整个时间的比例较大。
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