原理 就是 利用 increment 原子增加操作
@RunWith(SpringRunner.class)
@SpringBootTest
public class RedisTest {
@Autowired
private StringRedisTemplate stringRedisTemplate;
private static final String ORDER_NUMBER_PREFIX = "0";
private static final String REDIS_ORDER_NUMBER_KEY = "orderNo";
private static final DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyyMMddHHmmss");
private static final Lock lock = new ReentrantLock();
private static List<String> list = Collections.synchronizedList(new ArrayList<>());
/**
* 20121212121212 + 3位递增
*/
@Test
public void test() throws InterruptedException {
int count = 2000;
CyclicBarrier barrier = new CyclicBarrier(count, () -> {
try {
System.out.println(" 全部就位... ");
System.out.println(" 3");
Thread.sleep(1000);
System.out.println(" 2");
Thread.sleep(1000);
System.out.println(" 1");
Thread.sleep(1000);
System.out.println(" 开始 GO.");
} catch (InterruptedException e) {
e.printStackTrace();
}
});
ExecutorService executor = Executors.newFixedThreadPool(count);
for (int i = 0; i < count; i++) {
executor.execute(() -> {
try {
System.out.println("Thread " + Thread.currentThread().getName() + "就位");
barrier.await();
System.out.println("Thread " + Thread.currentThread().getName() + "执行");
getOrderNo();
} catch (Exception e) {
e.printStackTrace();
}
});
}
//保证所有线程执行完毕
Thread.sleep(600000);
executor.shutdown();
}
private String getOrderNo() {
lock.lock();
String orderNo = null;
try {
// 获取redis此时订单号
if (StringUtils.isEmpty(stringRedisTemplate.opsForValue().get(REDIS_ORDER_NUMBER_KEY))) {
// 初始化
stringRedisTemplate.opsForValue().set(REDIS_ORDER_NUMBER_KEY, LocalDateTime.ofInstant(new Date().toInstant(), ZoneId.systemDefault()).format(dateTimeFormatter) + "000");
}
// 获取当前订单号2019 0628 173739 001
long currentOrder = stringRedisTemplate.opsForValue().increment(REDIS_ORDER_NUMBER_KEY, 1L);
long current = Long.valueOf(String.valueOf(currentOrder).substring(0, 14));
// 当前时间
long now = Long.valueOf(LocalDateTime.ofInstant(new Date().toInstant(), ZoneId.systemDefault()).format(dateTimeFormatter));
if (current != now) {
if (now < current) {
// 循环等待到下一秒 重新从001 开始
while (true) {
now = Long.valueOf(LocalDateTime.ofInstant(new Date().toInstant(), ZoneId.systemDefault()).format(dateTimeFormatter));
if (now == current) {
// 重新 001 开始
stringRedisTemplate.opsForValue().set(REDIS_ORDER_NUMBER_KEY, now + "000");
orderNo = ORDER_NUMBER_PREFIX + stringRedisTemplate.opsForValue().increment(REDIS_ORDER_NUMBER_KEY, 1L);
break;
}
}
} else {
// 重新 001 开始
stringRedisTemplate.opsForValue().set(REDIS_ORDER_NUMBER_KEY, now + "000");
orderNo = ORDER_NUMBER_PREFIX + stringRedisTemplate.opsForValue().increment(REDIS_ORDER_NUMBER_KEY, 1L);
}
} else {
// 直接返回当前的订单号
orderNo = ORDER_NUMBER_PREFIX + currentOrder;
}
System.out.println(LocalDateTime.now() + ":orderNo = " + orderNo + ":flag=" + list.contains(orderNo));
list.add(orderNo);
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
return orderNo;
}
}
2019-06-29T00:08:01.999:orderNo = 020190629000801515:flag=false
2019-06-29T00:08:02:orderNo = 020190629000802001:flag=false
2019-06-29T00:08:02.001:orderNo = 020190629000802002:flag=false
2019-06-29T00:08:02.492:orderNo = 020190629000802999:flag=false
2019-06-29T00:08:03:orderNo = 020190629000803001:flag=false
2019-06-29T00:08:03.001:orderNo = 020190629000803002:flag=false
