使用synchronized关键字或者Lock锁控制并发

示例代码：

使用synchronized关键字：

public class AtomicLongDemo{ private static long count = 0; private static final Object lock = new Object();

public static void main(String[] args) {
    for (int i = 0; i < 10; i++) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int j = 0; j < 10000; j++) {
                    synchronized (lock) {
                        count++;
                    }
                }
            }
        }).start();
    }

    try {
        Thread.sleep(2000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    System.out.println("count=" + count);
}

}

使用Lock锁：

public class AtomicLongDemo{ private static long count = 0; private static Lock lock = new ReentrantLock();

public static void main(String[] args) {
    for (int i = 0; i < 10; i++) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int j = 0; j < 10000; j++) {
                    lock.lock();
                    try {
                        count++;
                    } finally {
                        lock.unlock();
                    }
                }
            }
        }).start();
    }

    try {
        Thread.sleep(2000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    System.out.println("count=" + count);
}

}