線程與線程池，實例比較。，線程池實例比較

線程與線程池，實例比較。，線程池實例比較

線程池：

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());

輸出結果：

1 172
2 200000

線程：

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());

輸出結果：

1 33556
2 200000

總結：差異在於線程池是復用線程的，而不使用線程池是每次都要去創建線程。線程中執行工作很簡單，創建線程的開銷占整個時間的比例較大。