根据时间戳生成有序id （菜鸟版）

代码

@Slf4j
public class NumUtil {

    private static long tmpID = 0;
    private static final long LOCK_TIME = 1;
    private static final long INCREASE_STEP = 1;
    private static SimpleDateFormat sdf = new SimpleDateFormat("yyMMddHHmmssSSS");
    private static final Lock LOCK = new ReentrantLock();


    public static long nextPkId() throws InterruptedException {
        //当前：（年、月、日、时、分、秒、毫秒）
        long timeCount;
        if (LOCK.tryLock(LOCK_TIME, TimeUnit.SECONDS)) {
            timeCount = Long.parseLong(sdf.format(new Date()));
            try {
                if (tmpID < timeCount) {
                    tmpID = timeCount;
                } else {
                    tmpID += INCREASE_STEP;
                    timeCount = tmpID;
                }
                return timeCount;
            } finally {
                LOCK.unlock();
            }
        } else {
            log.error("lock failed");
            return nextPkId();

        }
    }
}

测试

public static void numTest() {
        ExecutorService executorService = Executors.newCachedThreadPool();
        int n = 10000;
        List<Long> list = new ArrayList<>();
        CountDownLatch latch = new CountDownLatch(n);
        for (int i = 0; i < n; i++) {
            executorService.execute(() -> {
                //执行业务请求
                try {
                    list.add(NumUtil.nextPkId());
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                latch.countDown();
            });
        }
        try {
            // 一定记得加上timeout时间，防止阻塞主线程
            latch.await(3000, TimeUnit.MILLISECONDS);
        } catch (InterruptedException e) {
            log.error(e.getMessage());
        }
        //4.等待所有子任务完成，组装内容
        while (list.size() < n) {
            log.info("集合长度 >>> {}",list.size());
        }
        //5.关闭线程池
        executorService.shutdown();

        for (Long aLong : list) {
            System.out.println(aLong);
        }
    }