秒杀系统—5.第二版升级优化的技术文档三
大纲
8.秒杀系统的秒杀库存服务实现
9.秒杀系统的秒杀抢购服务实现
10.秒杀系统的秒杀下单服务实现
11.秒杀系统的页面渲染服务实现
12.秒杀系统的页面发布服务实现
8.秒杀系统的秒杀库存服务实现
(1)秒杀商品的库存在Redis中的结构
(2)库存分片并同步到Redis的实现
(3)查询秒杀商品的实时库存的实现
(4)消费支付成功的消息时增减库存
(5)消费订单取消的消息时增减库存
(1)秒杀商品的库存在Redis中的结构
//每个秒杀商品的库存结构都是⼀个Hash
"seckillStock:activityId:skuId": {
"salableStock":100,//可销售库存
"lockedStock":10,//锁定库存
"soldStock":20//已销售库存
}
"seckillStock:1001:100001": {
"salableStock":500,//可销售库存
"lockedStock":50,//锁定库存
"soldStock":100//已销售库存
}
(2)库存分片并同步到Redis的实现
首先构建库存在各Redis节点上的库存数据Map对象，然后遍历Redis的节点，接着通过hset命令保存到Redis中(不用设置过期时间)。
//库存分片和同步库存
@Component
public class TriggerStockTask {
@Autowired
private ActivityService activityService;
@Autowired
private ActivitySkuRefService activitySkuRefService;
@Autowired
private LockService lockService;
@Autowired
private InventoryApi inventoryApi;
@Scheduled(fixedDelay = 10_000)
public void run() {
String lockToken = lockService.tryLock(CacheKey.TRIGGER_STOCK_LOCK, 1, TimeUnit.SECONDS);
if (lockToken == null) {
return;
}
log.info("触发库存分片和同步库存，获取分布式锁成功, lockToken={}", lockToken);
try {
//查询已经渲染好页面的所有秒杀活动
List<Activity> activities = activityService.queryListForTriggerStockTask();
if (CollectionUtils.isEmpty(activities)) {
return;
}
for (Activity activity : activities) {
List<ActivitySkuRef> activitySkuRefs = activitySkuRefService.queryByActivityId(activity.getId());
if (CollectionUtils.isEmpty(activitySkuRefs)) {
continue;
}
//要进行缓存初始化的商品，封装库存初始化请求
List<SyncProductStockRequest> request = new ArrayList<>();
for (ActivitySkuRef activitySkuRef : activitySkuRefs) {
SyncProductStockRequest syncProductStockRequest =
SyncProductStockRequest.builder()
.activityId(activitySkuRef.getActivityId())
.skuId(activitySkuRef.getSkuId())
.seckillStock(activitySkuRef.getSeckillStock()).build();
request.add(syncProductStockRequest);
}
//把封装的库存初始化请求，发送到秒杀库存服务里
//每个商品的库存数据都会分散到各个Redis节点上去，实现对商品库存分片存放
if (inventoryApi.syncStock(request)) {
log.info("触发库存分片和同步库存，调用库存接口将商品库存同步到Redis");
activityService.updateStatus(activity.getId(), ActivityStatusVal.PAGE_RENDERED.getCode(), ActivityStatusVal.INVENTORY_SYNCED.getCode());
log.info("触发库存分片和同步库存，将秒杀活动的状态修改为库存已同步");
//完成库存分片后，用户就可以对商品发起秒杀抢购了
} else {
log.error("触发库存分片和同步库存，库存同步失败");
}
}
} finally {
lockService.release(CacheKey.TRIGGER_STOCK_LOCK, lockToken);
log.info("触发库存分片和同步库存，释放分布式锁");
}
}
}
@Service
public class ActivityServiceImpl implements ActivityService {
@Autowired
private ActivityMapper activityMapper;
...
//获取状态是已渲染好页面的秒杀活动
@Override
public List<Activity> queryListForTriggerStockTask() {
QueryWrapper<Activity> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("status", ActivityStatusVal.PAGE_RENDERED.getCode());
return activityMapper.selectList(queryWrapper);
}
...
}
@FeignClient("demo-seckill-inventory-service")
@RequestMapping("/inventory")
public interface InventoryApi {
@PostMapping("/syncStock")
Boolean syncStock(@RequestBody List<SyncProductStockRequest> request);
...
}
@RestController
@RequestMapping("/inventory")
public class InventoryController {
@Autowired
private InventoryService inventoryService;
@PostMapping("/syncStock")
Boolean syncStock(@RequestBody List<SyncProductStockRequest> request) {
for (SyncProductStockRequest syncProductStockRequest : request) {
inventoryService.syncStock(syncProductStockRequest.getActivityId(), syncProductStockRequest.getSkuId(), syncProductStockRequest.getSeckillStock());
log.info("同步商品库存, syncProductStockRequest={}", JSON.toJSONString(syncProductStockRequest));
}
return Boolean.TRUE;
}
...
}
@Service
public class InventoryServiceImpl implements InventoryService {
@Autowired
private CacheSupport cacheSupport;
...
@Override
public Boolean syncStock(Long activityId, Long skuId, Integer stock) {
//下面这种分片方式会有一个问题
//比如，现在库存是10，Redis的节点个数是6
//那么按照如下方式，最后的结果是：1、1、1、1、1、5
//但是我们希望尽可能均分成：2、2、2、2、1、1
//int redisCount = cacheSupport.getRedisCount();
//int stockPerRedis = stock / redisCount;
//int stockLastRedis = stock - (stockPerRedis * (redisCount - 1));
//所以改成如下这种分片方式
//首先获取Redis实例数量，将库存拆分为与Redis实例个数一样的redisCount个库存分片
int redisCount = cacheSupport.getRedisCount();
//然后将具体的库存分片结果存放到一个Map中
//其中key是某Redis节点的索引，value是该Redis节点应该分的库存
Map<Integer, Integer> map = new HashMap<>();
for (int i = 0; i < stock; i++) {
//均匀把stock的数据分散放到我们的各个节点上去
int index = i % redisCount;
//对每个节点的库存数量不停进行累加操作
map.putIfAbsent(index, 0);
map.put(index, map.get(index) + 1);
}
List<Map<String, String>> stockList = new ArrayList<>();
for (int i = 0; i < redisCount; i++) {
Map<String, String> stockMap = new HashMap<>();
stockMap.put(CacheKey.SALABLE_STOCK, map.get(i) + "");
stockMap.put(CacheKey.LOCKED_STOCK, "0");
stockMap.put(CacheKey.SOLD_STOCK, "0");
stockList.add(stockMap);
log.info("库存分片 stockMap={}", JSON.toJSONString(stockMap));
}
cacheSupport.hsetOnAllRedis(CacheKey.buildStockKey(activityId, skuId), stockList);
return Boolean.TRUE;
}
...
}
public class RedisCacheSupport implements CacheSupport {
private final JedisManager jedisManager;
public RedisCacheSupport(JedisManager jedisManager) {
this.jedisManager = jedisManager;
}
@Override
public int getRedisCount() {
return jedisManager.getRedisCount();
}
...
@Override
public void hsetOnAllRedis(String key, List<Map<String, String>> hashList) {
for (int i = 0; i < jedisManager.getRedisCount(); i++) {
//通过hset命令，向每个Redis节点写入库存分片数据
try (Jedis jedis = jedisManager.getJedisByIndex(i)) {
jedis.hset(key, hashList.get(i));
}
}
}
...
}
public class JedisManager implements DisposableBean {
private static final Logger LOGGER = LoggerFactory.getLogger(JedisManager.class);
private final List<JedisPool> jedisPools = new ArrayList<>();
public JedisManager(JedisConfig jedisConfig) {
JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();
jedisPoolConfig.setMaxTotal(jedisConfig.getMaxTotal());//Jedis连接池，最大有多少个连接实例
jedisPoolConfig.setMaxIdle(jedisConfig.getMaxIdle());
jedisPoolConfig.setMinIdle(jedisConfig.getMinIdle());
//加载和解析Redis集群地址
for (String addr : jedisConfig.getRedisAddrs()) {
String[] ipAndPort = addr.split(":");
String redisIp = ipAndPort[0];
int redisPort = Integer.parseInt(ipAndPort[1]);
//针对每个Redis实例，都会去建立一个Jedis Pool，每个Redis实例都需要一个连接池
JedisPool jedisPool = new JedisPool(jedisPoolConfig, redisIp, redisPort);
LOGGER.info("创建JedisPool, jedisPool={}", jedisPool);
//针对各个Redis实例，都有一个连接池
jedisPools.add(jedisPool);
}
}
public int getRedisCount() {
return jedisPools.size();
}
public Jedis getJedisByIndex(int index) {
return jedisPools.get(index).getResource();
}
public Jedis getJedisByHashKey(long hashKey) {
hashKey = Math.abs(hashKey);
int index = (int) (hashKey % getRedisCount());
return getJedisByIndex(index);
}
public Jedis getJedisByHashKey(int hashKey) {
hashKey = Math.abs(hashKey);
int index = hashKey % getRedisCount();
return getJedisByIndex(index);
}
@Override
public void destroy() throws Exception {
for (JedisPool jedisPool : jedisPools) {
LOGGER.info("关闭jedisPool, jedisPool={}", jedisPool);
jedisPool.close();
}
}
}
(3)查询秒杀商品的实时库存的实现
@RestController
@RequestMapping("/inventory")
public class InventoryController {
@Autowired
private InventoryService inventoryService;
...
@PostMapping("/queryCurrentStock")
List<ProductStockVo> queryCurrentStock(@RequestBody QueryCurrentStockRequest request) {
List<ProductStockVo> resultList = new ArrayList<>();
Long activityId = request.getActivityId();
for (Long skuId : request.getSkuIds()) {
ProductStockVo productStockVo = inventoryService.queryCurrentStock(activityId, skuId);
resultList.add(productStockVo);
}
return resultList;
}
...
}
@Service
public class InventoryServiceImpl implements InventoryService {
@Autowired
private CacheSupport cacheSupport;
//从Redis中获取当前库存数据
@Override
public ProductStockVo queryCurrentStock(Long activityId, Long skuId) {
List<Map<String, String>> stockList = cacheSupport.hgetAllOnAllRedis(CacheKey.buildStockKey(activityId, skuId));
int salableStock = 0;
int lockedStock = 0;
int soldStock = 0;
for (Map<String, String> stockMap : stockList) {
salableStock += Integer.parseInt(stockMap.get(CacheKey.SALABLE_STOCK));
lockedStock += Integer.parseInt(stockMap.get(CacheKey.LOCKED_STOCK));
soldStock += Integer.parseInt(stockMap.get(CacheKey.SOLD_STOCK));
}
return ProductStockVo.builder().activityId(activityId).skuId(skuId).salableStock(salableStock).lockedStock(lockedStock).soldStock(soldStock).build();
}
...
}
public class RedisCacheSupport implements CacheSupport {
private final JedisManager jedisManager;
public RedisCacheSupport(JedisManager jedisManager) {
this.jedisManager = jedisManager;
}
@Override
public int getRedisCount() {
return jedisManager.getRedisCount();
}
...
//由于一个商品的库存数据可能会分散在各个Redis节点上
//所以需要从各个Redis节点查询商品库存数据，然后合并起来才算是一份总的数据
@Override
public List<Map<String, String>> hgetAllOnAllRedis(String key) {
List<Map<String, String>> list = new ArrayList<>();
for (int i = 0; i < jedisManager.getRedisCount(); i++) {
try (Jedis jedis = jedisManager.getJedisByIndex(i)) {
list.add(jedis.hgetAll(key));
}
}
return list;
}
...
}
(4)消费支付成功的消息时增减库存
由于有多个Redis实例，那么应该去哪台Redis上增减库存呢？在⽀付成功时需要做的操作是减少锁定库存 + 增加已销售库存。
但是不能随便找⼀台Redis就去执行这个操作，必须是抢购扣减库存时从哪个实例上减的，就到哪个实例上去执行操作。否则库存就会乱，比如会出现有些机器上库存是负的。
所以在秒杀抢购服务中扣减库存时：对于每个抢购请求，都⽣成⼀个long类型的⾃增序列。这个自增序列不需要全局唯⼀，甚⾄也不需要实例内唯⼀。通过这个自增序列来记录从哪台Redis实例上扣减库存，然后把这个⾃增序列透传到订单上去，⽐如透传到订单的扩展信息。
这样消费订单⽀付成功的消息时，就能找到当时扣减库存的那台Redis，然后就可以进行⽀付成功后的库存扣减操作了。
@Component
@RocketMQMessageListener(topic = QueueKey.QUEUE_PAY_ORDER, consumerGroup = "pageOrderGroup")
public class PayOrderListener implements RocketMQListener<String> {
@Autowired
private InventoryService inventoryService;
@Override
public void onMessage(String messageString) {
log.info("收到订单支付成功的消息，mesasge={}", messageString);
OrderPayMessage message = JSON.parseObject(messageString, OrderPayMessage.class);
inventoryService.confirmStock(message.getSequence(), message.getActivityId(), message.getSkuId());
log.info("确认订单支付对应的商品库存");
}
}
@Service
public class InventoryServiceImpl implements InventoryService {
@Autowired
private CacheSupport cacheSupport;
...
@Override
public Boolean confirmStock(Long sequence, Long activityId, Long skuId) {
String stockKey = CacheKey.buildStockKey(activityId, skuId);
String script = LuaScript.buildConfirmStockScript(stockKey);
cacheSupport.eval(sequence, script);
return Boolean.TRUE;
}
...
}
public interface LuaScript {
//消费⽀付成功的消息时增减库存
String CONFIRM_STOCK = "local stockKey = '%s';"
+ "local lockedStock = redis.call('hget', stockKey, 'lockedStock') + 0;"
+ "local soldStock = redis.call('hget', stockKey, 'soldStock') + 0;"
+ "redis.call('hset', stockKey, 'lockedStock', lockedStock - 1);"
+ "redis.call('hset', stockKey, 'soldStock', soldStock + 1);";
static String buildConfirmStockScript(String key) {
return String.format(CONFIRM_STOCK, key);
}
...
}
public class RedisCacheSupport implements CacheSupport {
private final JedisManager jedisManager;
public RedisCacheSupport(JedisManager jedisManager) {
this.jedisManager = jedisManager;
}
...
@Override
public Object eval(Long hashKey, String script) {
try (Jedis jedis = jedisManager.getJedisByHashKey(hashKey)) {
return jedis.eval(script);
}
}
...
}
(5)消费订单取消的消息时增减库存
@Component
@RocketMQMessageListener(topic = QueueKey.QUEUE_CANCEL_ORDER, consumerGroup = "cancelOrderGroup")
public class CancelOrderListener implements RocketMQListener<String> {
@Autowired
private InventoryService inventoryService;
@Override
public void onMessage(String messageString) {
log.info("收到订单取消的消息，mesasge={}", messageString);
OrderCancelMessage message = JSON.parseObject(messageString, OrderCancelMessage.class);
inventoryService.releaseStock(message.getSequence(), message.getActivityId(), message.getSkuId());
log.info("释放掉取消订单对应的商品库存");
}
}
@Service
public class InventoryServiceImpl implements InventoryService {
@Autowired
private CacheSupport cacheSupport;
...
@Override
public Boolean releaseStock(Long sequence, Long activityId, Long skuId) {
String stockKey = CacheKey.buildStockKey(activityId, skuId);
String script = LuaScript.buildReleaseStockScript(stockKey);
cacheSupport.eval(sequence, script);
return Boolean.TRUE;
}
...
}
public interface LuaScript {
...
//消费订单超时未⽀付的消息时增减库存 + 消费订单取消的消息时增减库存
String RELEASE_STOCK = "local stockKey = '%s';"
+ "local salableStock = redis.call('hget', stockKey, 'salableStock') + 0;"
+ "local lockedStock = redis.call('hget', stockKey, 'lockedStock') + 0;"
+ "redis.call('hset', stockKey, 'salableStock', salableStock + 1);"
+ "redis.call('hset', stockKey, 'lockedStock', lockedStock - 1);";
static String buildReleaseStockScript(String key) {
return String.format(RELEASE_STOCK, key);
}
}
9.秒杀系统的秒杀抢购服务实现
(1)秒杀抢购的时序图
(2)秒杀抢购的请求处理入口
(3)校验是否已抢购过某商品的实现
(4)校验在某活动下抢购不同商品数的实现
(5)扣减库存的实现
(6)发送异步下单消息的实现
(7)响应用户抢购成功的实现
(1)秒杀抢购的时序图
(2)秒杀抢购的请求处理入口
这里使用Servlet 3.0的异步化功能来提升性能，具体就是：首先及时释放掉Tomcat的线程，保证Response对象不会被关闭，然后把请求交给自定义的业务线程池去处理。由于秒杀抢购涉及的操作步骤比较多，所以使用了责任链模式来进行编码。
@RestController
@RequestMapping("/purchase")
public class PurchaseController {
@Autowired
private BossEventBus bossEventBus;
@PostMapping
public void seckillPurchase(@RequestBody PurchaseRequest request, HttpServletRequest servletRequest, HttpServletResponse servletResponse) {
String validateResult = request.validateParams();
if (Objects.nonNull(validateResult)) {
servletResponse.setCharacterEncoding("UTF-8");
servletResponse.setContentType("application/json;charset=UTF-8");
try (ServletOutputStream out = servletResponse.getOutputStream()) {
String s = "{\"success\":false, \"info\":\"" + validateResult + "\"}";
out.write(s.getBytes(StandardCharsets.UTF_8));
out.flush();
} catch (IOException e) {
e.printStackTrace();
}
} else {
//对并发HTTP请求的两种处理方式：
//方式一：同步处理请求，即直接返回响应给前端
//基于Boss + Worker双总线架构，首先将抢购的请求直接放入队列中，然后直接返回响应给前端；
//接着再基于队列中转 + 线程池异步并发的去处理抢购请求；
//从而最大幅度提升抢购服务的并发能力和吞吐量；
//也就是说：
//抢购请求发送到这里以后，会直接进入内存队列，然后进行返回，这样可将抢购接口的性能提到最高；
//此时前端界面会提示正在抢购中，请耐心等待抢购结果；
//接着前端会每隔几秒发送一个请求到后台来查询本次抢购的结果；
//方式二：采用Servlet 3.0的异步化架构，异步处理请求，即等待监听后再返回响应给前端
//基于Boss + Worker双总线架构，请求过来后也是立刻将请求提交到内存队列，但并没有直接返回响应给前端；
//1.首先请求提交到内存队列后会进行异步化处理：
//所以此时可以马上释放Tomcat里的业务线程，让处理当前请求的Tomcat线程可以去处理其他请求；
//通过这种方式，可以避免线程同步阻塞等待结果返回，从而大幅度提升抢购服务的并发能力和吞吐量；
//2.其次没有直接返回响应给前端：
//这是因为请求的响应会通过Servlet 3.0提供的AsyncListener收到通知后才进行返回；
//当异步化处理完请求后，就会通知AsyncListener，此时Tomcat才会把请求的响应返回前端；
//开启请求的异步化处理，避免Tomcat的线程阻塞
AsyncContext asyncContext = servletRequest.startAsync();
asyncContext.setTimeout(5000);
//添加ServletAsyncListener，当HTTP请求被异步处理完时，就会通知Tomcat可以将响应返回给前端
asyncContext.addListener(new ServletAsyncListener());
PurchaseContext purchaseContext = new PurchaseContext();
purchaseContext.setAsyncContext(asyncContext);
purchaseContext.setActivityId(request.getActivityId());
purchaseContext.setSkuId(request.getSkuId());
purchaseContext.setUserId(request.getUserId());
//秒杀抢购时涉及的步骤比较多，这里采用了责任链模式
bossEventBus.publish("step1", new Step1CheckProduct(), purchaseContext);
}
}
}
public class BossEventBus {
private final Disruptor<BossEvent> bossRingBuffer;
public BossEventBus(BossConfig bossConfig, WorkerConfig workerConfig) {
//双总线架构设计：
//BossEventBus -> 事件会分发到不同的WorkEventBus -> 不同的线程池来进行并发处理
//Boss事件总线：即主事件总线，只有一个
//比如用来处理每一个秒杀请求
//Work事件总线：即工作任务事件总线，有多个，不同类型
//比如用来处理一个秒杀请求的每一个具体步骤
//每个步骤处理完之后又发送到Work事件总线处理下一个步骤
//所以先进来的请求可能不会先被处理完
//双总线架构的设计思想：
//通过将一个请求拆分为多个步骤，当需要处理并发的多个请求时，就可以用多个线程池分别处理每个步骤，从而提升处理并发请求的速度
//因为一段代码的执行可能需要一定的时间，一个CPU时间片并不能执行完，需要很多个CPU时间片来执行，从而产生CPU时间片的等待
//如果将一段代码的执行拆分为几个步骤，那么一个步骤的执行可能一个CPU时间片就执行完了，不会产生比较多的CPU时间片等待
//首先所有的Event先进入BossEventBus里的Disruptor
//然后BossEventBus.Disruptor里的线程会把Event交给BossEventHandler处理
//接着BossEventHandler再将这些Event分发到各自对应的WorkEventBus.Disruptor
//而WorkEventBus.Disruptor里的线程又会把Event拿出来交给WorkEventHandler处理
//最后WorkEventHandler则将Event交给监听的EventListener，由EventListener中的线程池来并发处理
//1.先准备好WorkEventBus
//比如用来处理一个秒杀请求的每个具体步骤Step
WorkEventBusManager workEventBusManager = WorkEventBusManager.getSingleton();
for (WorkerConfig.Config config : workerConfig.getWorkers()) {
workEventBusManager.register(config);
}
//2.再准备好BossEventBus
//比如用来处理每一个秒杀请求
bossRingBuffer = new Disruptor<>(BossEvent::new, bossConfig.getRingbufferSize(), NamedDaemonThreadFactory.getInstance("BossEventBus"));
BossEventHandler[] eventHandlers = new BossEventHandler[bossConfig.getEventHandlerNum()];
for (int i = 0; i < eventHandlers.length; i++) {
eventHandlers[i] = new BossEventHandler();
}
bossRingBuffer.handleEventsWithWorkerPool(eventHandlers);
bossRingBuffer.start();
}
public boolean publish(String channel, BaseEvent event, AsyncContext context) {
//EventTranslator就是把传入的参数，转换为Disruptor里面的Event对象
EventTranslator<BossEvent> translator = (e, s) -> {
e.channel = channel;
e.event = event;
e.context = context;
};
//把封装的BossEvent发布到Disruptor内存队列里
//发布成功后，Disruptor内部线程会消费和处理内存队列里的BossEvent
//也就是会把BossEvent交给BossEventHandler来进行处理
boolean success = bossRingBuffer.getRingBuffer().tryPublishEvent(translator);
if (!success) {
//如果异步发布event到内存队列里失败了
}
return success;
}
}
public class BossEventHandler implements WorkHandler<BossEvent> {
@Override
public void onEvent(BossEvent event) throws Exception {
try {
dispatchBossEvent(event);
} finally {
event.clear();
}
}
//事件分发
@SuppressWarnings("unchecked")
private void dispatchBossEvent(BossEvent event) {
//1.根据channel获取到对应的WorkEventBus
WorkEventBus workEventBus = WorkEventBusManager.getSingleton().getWorkEventBus(event.channel);
//2.根据事件类型获取到对应的Listener，把之前注册的Listener拿出来
List<EventListener> eventListeners = workEventBus.getEventListeners(event.event);
//3.封装WorkEvent
EventTranslator<WorkEvent> translator = (e, s) -> {
e.event = event.event;//事件类型
e.context = event.context;//数据上下文
e.listeners = eventListeners;//注册到WorkEventBus里的Listener
};
//4.把Event分发到channel指定的WorkEventBus里去
//WorkEvent会进入到内存队列里，内部会有一个线程，拿到WorkEvent，交给WorkEventHandler处理
boolean publish = workEventBus.publish(translator);
if (!publish) {
//如果发布到WorkEventBus时，遇到队列满的问题，那么publish就会为false
}
}
}
public abstract class BasePurchaseListener<E extends BaseEvent> implements EventListener<BaseEvent> {
@Autowired
protected BossEventBus bossEventBus;
@Autowired
protected ExecutorService executorService;
@Autowired
protected CacheSupport cacheSupport;
@Override
public void onEvent(BaseEvent event, AsyncContext eventContext) {
PurchaseContext purchaseContext = (PurchaseContext) eventContext;
doThisStep(((E) event), purchaseContext);
}
protected abstract void doThisStep(E event, PurchaseContext purchaseContext);
protected void response(javax.servlet.AsyncContext asyncContext, boolean success, String info) {
ServletResponse response = asyncContext.getResponse();
response.setCharacterEncoding("UTF-8");
response.setContentType("application/json;charset=UTF-8");
try (ServletOutputStream out = response.getOutputStream()) {
String s = "{\"success\":" + success + ", \"info\":\"" + info + "\"}";
out.write(s.getBytes(StandardCharsets.UTF_8));
out.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
asyncContext.complete();
}
}
}
(3)校验是否已抢购过某商品的实现
//校验用户是否已经抢购过某个秒杀商品
@Component
@Channel("step1")
public class Step1Listener extends BasePurchaseListener<Step1CheckProduct> {
@Override
public boolean accept(BaseEvent event) {
return event instanceof Step1CheckProduct;
}
@Override
protected void doThisStep(Step1CheckProduct event, PurchaseContext purchaseContext) {
executorService.execute("step1", () -> {
Long activity = purchaseContext.getActivityId();
Long userId = purchaseContext.getUserId();
Long skuId = purchaseContext.getSkuId();
//以秒杀活动ID + 用户ID + skuID来构建key
String key = CacheKey.buildCheckProductKey(activity, userId, skuId);
//进行防重处理：
//如果用户对这个秒杀活动下的这个秒杀商品还没抢购过，则可以发起抢购
//如果已经抢购过了，则不能重复抢购
if (!cacheSupport.exists(key)) {
log.info("校验用户是否已经抢购过某秒杀商品，用户还未抢购过");
//用户还没成功抢购过这个商品，则进入第二步校验用户在该秒杀活动中抢购过的不同商品数
bossEventBus.publish("step2", new Step2CheckUser(), purchaseContext);
return;
}
response(purchaseContext.getAsyncContext(), false, "你已经抢购过该商品了");
});
}
}
(4)校验在某活动下抢购不同商品数的实现
//校验用户在某秒杀活动下抢购过的不同商品数
//最多允许用户抢购某个秒杀活动中的3个不同商品，这在一定程度上防止用户是黄牛或恶意抢购所有商品
@Component
@Channel("step2")
public class Step2Listener extends BasePurchaseListener<Step2CheckUser> {
@Override
public boolean accept(BaseEvent event) {
return event instanceof Step2CheckUser;
}
@Override
protected void doThisStep(Step2CheckUser event, PurchaseContext purchaseContext) {
executorService.execute("step2", () -> {
Long activity = purchaseContext.getActivityId();
Long userId = purchaseContext.getUserId();
//以秒杀活动Id + 用户ID来构建key
String key = CacheKey.buildCheckUserKey(activity, userId);
Long incr = cacheSupport.incr(key);//返回自增后的值
if (incr <= 3) {
//10分钟内，一个用户在一个秒杀活动里最多抢购3个不同的商品
cacheSupport.expire(key, 600);
log.info("校验用户在某秒杀活动下抢购过的不同商品数，在3次以内");
bossEventBus.publish("step3", new Step3LockStock(), purchaseContext);
return;
}
response(purchaseContext.getAsyncContext(), false, "已抢购过的不同商品数超出限制");
});
}
}
(5)扣减库存的实现
⾸先将标记请求的⾃增序列加1，然后⽤这个⾃增序列确定⼀台Redis实例来执⾏扣减库存的脚本。
如果扣减成功，则直接返回抢购成功。如果扣减失败，那么不再获取新的⾃增序列，⽽是在原来的基础之上在加1，然后继续到下⼀台机器扣减库存。如果⼀直加了所有的Redis节点数还没有扣减库存成功，那么可以认为此时秒杀商品整体售罄了，返回⽤户该秒杀商品已售罄。
通过在扣减库存时，在Redis标记请求，也可以进行超时补偿处理。比如可能秒杀服务在Redis扣减完库存后，出现宕机等异常无法继续处理。当然如果在页面渲染时也出现中断的情况，也可以基于Redis实现补偿。
//扣减库存
@Component
@Channel("step3")
public class Step3Listener extends BasePurchaseListener<Step3LockStock> {
private static final AtomicLong sequencer = new AtomicLong();
private static final String SCRIPT = "local stockKey = '%s';"
+ "local salableStock = redis.call('hget', stockKey, 'salableStock') + 0;"
+ "local lockedStock = redis.call('hget', stockKey, 'lockedStock') + 0;"
+ "if(salableStock > 0) "
+ "then "
+ "redis.call('hset', stockKey, 'salableStock', salableStock - 1);"
+ "redis.call('hset', stockKey, 'lockedStock', lockedStock + 1);"
+ "return 'success';"
+ "else "
+ "return 'failure';"
+ "end;";
@Override
public boolean accept(BaseEvent event) {
return event instanceof Step3LockStock;
}
@Override
protected void doThisStep(Step3LockStock event, PurchaseContext purchaseContext) {
executorService.execute("step3", () -> {
//首先获取一个自增序列
//在第1次扣减库存时，用它来决定后续订单链路的库存扣减都应该到哪台Redis中去处理
//该序列会不停自增，多个线程过执行到这里时，会在多个Redis节点里进行RoundRobin轮询
long sequence = sequencer.incrementAndGet();
Long activity = purchaseContext.getActivityId();
Long userId = purchaseContext.getUserId();
Long skuId = purchaseContext.getSkuId();
String stockKey = CacheKey.buildStockKey(activity, skuId);
String script = String.format(SCRIPT, stockKey);
//获取Redis实例数量
int redisCount = cacheSupport.getRedisCount();
//从sequence到maxSequence的间隔就是Redis实例数量
long maxSequence = sequence + redisCount - 1;
String result;
//遍历循环与Redis实例数量一样多的次数
//首先通过sequence定位到一台用来扣减库存的起始Redis实例
//如果在这台起始Redis实例上没能扣减库存成功，说明在该起始Redis实例上没有库存了
//但此时其他的Redis实例上可能还有库存，所以需要尝试在下一台Redis实例上扣减库存
for (long i = sequence; i <= maxSequence; i++) {
log.info("扣减库存，sequence={}", i);
//针对指定的sequence序号，通过取模找到对应的Redis实例，来执行抢购脚本
result = (String) cacheSupport.eval(i, script);
if (StringUtils.equals(result, "success")) {
//扣减库存成功后，则把用户已经抢购成功的消息记录到Redis中
String key = CacheKey.buildCheckProductKey(activity, userId, skuId);
cacheSupport.set(key, "1");
cacheSupport.expire(key, 7200);
//需要记录是在哪台Redis实例上扣减库存，这样后面确认库存时，就可以到这台Redis实例上进行确认
purchaseContext.setSequence(i);
log.info("扣减库存，扣减库存成功，sequence={}", i);
//抢购成功后，进入下一步发送创建订单的消息到RocketMQ
bossEventBus.publish("step4", new Step4CreateOrder(), purchaseContext);
return;
}
}
response(purchaseContext.getAsyncContext(), false, "该商品已经售罄了");
});
}
}
(6)发送异步下单消息的实现
//发送异步创建秒杀订单的消息
@Component
@Channel("step4")
public class Step4Listener extends BasePurchaseListener<Step4CreateOrder> {
@Autowired
private RocketMQTemplate rocketMQTemplate;
@Override
public boolean accept(BaseEvent event) {
return event instanceof Step4CreateOrder;
}
@Override
protected void doThisStep(Step4CreateOrder event, PurchaseContext purchaseContext) {
executorService.execute("step4", () -> {
//发送异步下单的请求，会把自己扣减库存的redis实例对应的seqwuence序号
String message = OrderCreateMessage.builder()
.sequence(purchaseContext.getSequence())
.activityId(purchaseContext.getActivityId())
.userId(purchaseContext.getUserId())
.skuId(purchaseContext.getSkuId())
.count(1).build().toJsonString();
rocketMQTemplate.convertAndSend(QueueKey.QUEUE_CREATE_ORDER, message);
log.info("发送异步创建秒杀订单的消息");
bossEventBus.publish("step5", new Step5Response(), purchaseContext);
});
}
}
(7)响应用户抢购成功的实现
//响应用户抢购成功
@Component
@Channel("step5")
public class Step5Listener extends BasePurchaseListener<Step5Response> {
@Override
public boolean accept(BaseEvent event) {
return event instanceof Step5Response;
}
@Override
protected void doThisStep(Step5Response event, PurchaseContext purchaseContext) {
executorService.execute("step5", () -> {
log.info("给用户返回抢购成功的响应");
//通过Servlet 3.0的异步化上下文，发送一个响应结果即可
response(purchaseContext.getAsyncContext(), true, "恭喜您抢购成功");
});
}
}
10.秒杀系统的秒杀下单服务实现
这里会消费异步下单的消息，然后调⽤订单服务接⼝来创建秒杀订单。业务逻辑⽐较简单，但是需要考虑以下的问题：
一.正常情况
需要使⽤Redis进行消息去重，保证消息消费幂等。需要进行消费流控，比如调整MQ消费者的线程数、使⽤信号量或Guava限流。需要进行多线程下单。
二.异常情况
如果创建订单的接⼝调⽤失败，需要基于MQ的重试功能进⾏重试。如果重试还是失败，让消息进⼊MQ的死信队列。
//这里会基于Semaphore信号量来进行下单限流
//下单服务最大的技术难点就是控制下单频率，而秒杀时的瞬时单量会特别大
//所以创建秒杀订单时，如果不加控制地调用订单系统的接口进行下单，那么订单系统负载会很高
//Semaphore数量的设置
//可以根据订单系统可以抗下的最大并发数进行估算，比如按照最大并发数 * 80%、70%、60%、50%
//然后将估算出的数字设置到Semaphore里去，表示最多可允许同时创建多少个订单
//从而避免对订单系统造成过大的压力，实现削峰填谷，将瞬时高峰削了，通过低谷来慢慢下单
//用户在前端页面抢购成功后，会进入等待界面(比如显示圆圈不停地旋转)
//此时前端会定时发送请求给后端，比如每隔5s发送请求来检查下单是否成功
//如果秒杀活动开始瞬时产生了1w个订单
//而订单系统的一台机器每秒支持创建500个订单，那么需要20秒才能完成订单的创建，此时用户体验必然不好
//假如订单系统部署了4台4核8G的机器，那么每秒可以支持创建2000订单，那么瞬时1w个订单只需要5s就可以完成创建
@Component
@RocketMQMessageListener(topic = QueueKey.QUEUE_CREATE_ORDER, consumerGroup = "createOrderGroup")
public class CreateOrderListener implements RocketMQListener<String> {
//并发能力为500
private static final Semaphore SEMAPHORE = new Semaphore(500);
@Autowired
private CacheSupport cacheSupport;
@Autowired
private OrderApi orderApi;
@Override
public void onMessage(String messageString) {
SEMAPHORE.acquireUninterruptibly();
try {
handleMessage(messageString);
} finally {
SEMAPHORE.release();
}
}
private void handleMessage(String messageString) {
log.info("收到创建秒杀订单的消息，message={}", messageString);
OrderCreateMessage message = JSON.parseObject(messageString, OrderCreateMessage.class);
Long sequence = message.getSequence();
Long activityId = message.getActivityId();
Long userId = message.getUserId();
Long skuId = message.getSkuId();
Integer count = message.getCount();
//通过Redis来进行幂等控制，避免重复消费
String key = CacheKey.buildConsumeCreateOrderKey(sequence, activityId, userId, skuId);
if (cacheSupport.exists(key)) {
return;
} else {
//设置key的过期时间
cacheSupport.expire(key, 7200);
}
CreateOrderReuqest request = CreateOrderReuqest.builder()
.sequence(sequence)
.activityId(activityId)
.userId(userId)
.skuId(skuId)
.count(count)
.build();
//调用一个订单的接口进行下单
if (orderApi.createOrder(request)) {
log.info("调用依赖的订单系统创建秒杀订单");
} else {
throw new RuntimeException("创建订单失败");
}
}
}
@FeignClient("demo-order-service")
@RequestMapping("/order")
public interface OrderApi {
@PostMapping
Boolean createOrder(@RequestBody CreateOrderReuqest request);
}
@RestController
@RequestMapping("/order")
public class OrderController {
@Autowired
private OrderService orderService;
@Autowired
private ProductApi productApi;
@Autowired
private RocketMQTemplate rocketMQTemplate;
...
@PostMapping
public Boolean createOrder(@RequestBody CreateOrderReuqest request) {
log.info("收到创建订单的请求");
SkuVo skuVo = productApi.queryBySkuId(request.getSkuId());
log.info("调用商品系统接口查询商品, skuVo={}", skuVo);
Map<String, Object> attributes = new HashMap<>();
attributes.put("activityId", request.getActivityId());
attributes.put("sequence", request.getSequence());
Order order = Order.builder()
.userId(request.getUserId())
.skuId(request.getSkuId())
.count(request.getCount())
.amount(request.getCount() * skuVo.getSeckillPrice())
.type(Order.TYPE_SECKILL)
.status(Order.STATUS_CREATED)
.attributes(JSON.toJSONString(attributes))
.build();
orderService.save(order);
log.info("保存订单，orderId={}，order={}", order.getId(), JSON.toJSONString(order));
//发送一个延时消息：14 -> 延时10m，4 -> 延时30s
//messageDelayLevel：1s 5s 10s 30s 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 20m 30m 1h 2h
rocketMQTemplate.syncSend(QueueKey.QUEUE_CHECK_ORDER, MessageBuilder.withPayload(order.getId()).build(), 2000, 14);
log.info("发送订单延时检查消息");
return Boolean.TRUE;
}
...
}
11.秒杀系统的页面渲染服务实现
(1)数据库表的设计
(2)页面渲染的时序图
(3)消费页面渲染的消息和超时补偿机制
(4)页面渲染第一步—加载页面配置
(5)页面渲染第二步—下载页面模版
(6)页面渲染第三步—聚合数据
(7)页面渲染第四步—渲染页面
(8)页面渲染第五步—上传静态化页面
(9)页面渲染第六步—保存页面渲染日志
(10)页面渲染第七步—发送渲染成功的消息到MQ
(1)数据库表的设计
一.模版文件表
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
@TableName("seckill_page_template")
public class PageTemplate implements Serializable {
//主键
private Long id;
//模板名称
private String templateName;
//模板文件的url
private String templateUrl;
private Date createTime;
private Date updateTime;
}
二.页面配置表
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
@TableName("seckill_page_config")
public class PageConfig implements Serializable {
//主键
private Long id;
//模板文件id
private Long templateId;
//模板文件的url
private String templateUrl;
//页面名称
private String pageName;
//页面编码
private String pageCode;
//渲染页面的数据来源
private String aggrDataUrl;
private Date createTime;
private Date updateTime;
}
三.页面渲染流水表
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
@TableName("seckill_page_log")
public class PageLog implements Serializable {
private Long id;
//渲染开始的时间戳
private Long startTime;
private String bizData;
//渲染页面还是删除页面, 渲染是render, 删除是delete
private String opType;
//文件名
private String fileName;
//页面要发布到这些静态资源服务器上，格式ip1,ip2
private String serverIps;
//记录页面已经发布到哪些静态资源服务器上了
private String finishedServerIps;
//渲染结束的的时间戳
private Long completionTime;
//渲染时使用的模板id
private Long templateId;
//生成的静态页面的id
private String staticPageId;
//静态资源的访问地址
private String staticPageUrl;
//触发这个渲染任务的消息内容
private String msg;
//这次操作是否成功
private Boolean success;
//当操作失败时的错误信息
private String info;
private Date createTime;
private Date updateTime;
}
(2)页面渲染的时序图
说明：由于模版内容读多写少，而且数据量不大，所以可存放到Redis甚至内存。
(3)消费页面渲染的消息和超时补偿机制
注意：由于整个渲染流程比较多步骤，而且是基于Disruptor内存队列进行的。所以很可能出现机器重启时，导致页面渲染过慢或者中断等异常。此时可以通过超时补偿机制来解决。也就是在如下定时任务中，如果发现超过10分钟还没完成渲染，则重复推送渲染消息，毕竟即便页面渲染多次也会不影响最终渲染结果。
@Component
public class TriggerPageTask {
@Autowired
private ActivityService activityService;
@Autowired
private ActivitySkuRefService activitySkuRefService;
@Autowired
private LockService lockService;
@Autowired
private RocketMQTemplate rocketMQTemplate;
@Scheduled(fixedDelay = 10_000)
public void run() {
//通过加锁，可以确保，同时只有一个定时调度任务在处理页面渲染触发
String lockToken = lockService.tryLock(CacheKey.TRIGGER_PAGE_LOCK, 1, TimeUnit.SECONDS);
if (lockToken == null) {
return;
}
log.info("触发渲染页面，获取分布式锁成功, lockToken={}", lockToken);
try {
//在秒杀活动展示之前1小时开始渲染页面
//发起渲染条件是：showTime - now < 1小时，同时秒杀活动已通过审核
List<Activity> activities = activityService.queryListForTriggerPageTask();
if (CollectionUtils.isEmpty(activities)) {
return;
}
for (Activity activity : activities) {
Long id = activity.getId();
List<ActivitySkuRef> activitySkuRefs = activitySkuRefService.queryByActivityId(id);
if (CollectionUtils.isEmpty(activitySkuRefs)) {
continue;
}
//发送渲染秒杀活动商品列表页的消息
List<Long> skuIds = activitySkuRefs.stream().map(ActivitySkuRef::getSkuId).collect(Collectors.toList());
String renderActivityPageMessage = PageRenderMessage.builder()
.pageCode("seckill_activity")
.bizData(ImmutableMap.of("type", "activity", "activityId", id))
.params(ImmutableMap.of("activityId", id, "activityName", activity.getActivityName(), "startTime", activity.getStartTime(), "endTime", activity.getEndTime(), "skuIds", skuIds))
.fileName(FileNameUtils.generateSeckillActivityFilename(id))
.build().toJsonString();
rocketMQTemplate.syncSend(QueueKey.QUEUE_RENDER_PAGE, renderActivityPageMessage);
log.info("触发渲染页面，发送渲染商品列表页的消息, message={}", renderActivityPageMessage);
for (ActivitySkuRef activitySkuRef : activitySkuRefs) {
//发送渲染秒杀商品详情页的消息
Long skuId = activitySkuRef.getSkuId();
String renderProductPageMessage = PageRenderMessage.builder()
.pageCode("seckill_product")
.bizData(ImmutableMap.of("type", "product", "activityId", id, "skuId", skuId))
.params(ImmutableMap.of("skuId", skuId))
.fileName(FileNameUtils.generateSeckillProductFilename(skuId))
.build().toJsonString();
rocketMQTemplate.syncSend(QueueKey.QUEUE_RENDER_PAGE, renderProductPageMessage);
log.info("触发渲染页面，发送渲染商品详情页的消息, message={}", renderProductPageMessage);
}
//把秒杀活动的状态修改为页面渲染中
activityService.updateStatus(id, ActivityStatusVal.AUDIT_PASS.getCode(), ActivityStatusVal.PAGE_RENDERING.getCode());
log.info("触发渲染页面，把秒杀活动状态改成页面渲染中");
}
} finally {
lockService.release(CacheKey.TRIGGER_PAGE_LOCK, lockToken);
log.info("触发渲染页面，释放分布式锁");
}
}
}
@Component
@RocketMQMessageListener(topic = QueueKey.QUEUE_RENDER_PAGE, consumerGroup = "rendPageConsumer")
public class RenderPageListener implements RocketMQListener<String> {
//异步框架BossEventBus
@Autowired
private BossEventBus bossEventBus;
@Override
public void onMessage(String messageString) {
log.info("收到渲染页面的消息, message={}", messageString);
try {
JSONObject message = JSONObject.parseObject(messageString);
PageRenderContext context = new PageRenderContext();
context.setPageCode(message.getString("pageCode"));
context.setBizData(message.getJSONObject("bizData"));
context.setParams(message.getJSONObject("params"));
context.setFileName(message.getString("fileName"));
context.setPageLog(new PageLog());
context.getPageLog().setStartTime(System.currentTimeMillis());
context.getPageLog().setBizData(JSON.toJSONString(context.getBizData()));
context.getPageLog().setOpType("render");
context.getPageLog().setFileName(context.getFileName());
context.getPageLog().setServerIps(BussinessConfig.getNginxServerIps());
context.getPageLog().setMsg(messageString);
//页面渲染的步骤：
//加载页面配置 -> 下载页面模板 -> 聚合数据 -> 渲染页面 -> 上传静态化页面 -> 保存页面渲染日志 -> 发布页面渲染成功的消息
bossEventBus.publish(ChannelKey.CHANNEL_01_LOAD_PAGE_CONFIG, PageRenderEventHolder.EVENT_01, context);
} catch (Exception ignore) {
}
}
}
(4)页面渲染第一步—加载页面配置
@Component
@Channel(CHANNEL_01_LOAD_PAGE_CONFIG)
public class Event01Listener extends BaseRenderPageListener<Event01LoadPageConfig> {
@Autowired
private PageConfigService pageConfigService;
@Override
public boolean accept(BaseEvent event) {
return event instanceof Event01LoadPageConfig;
}
//页面渲染第一步：加载页面配置
//加载到页面配置后，才可以进行页面渲染
@Override
protected void doThisStep(Event01LoadPageConfig event, PageRenderContext context) {
//pageCode的取值是：seckill_product或seckill_activity
String pageCode = context.getPageCode();
//封装一个Runnable异步任务
Runnable task = () -> {
//根据pageCode来获取PageConfig页面配置
PageConfig pageConfig = pageConfigService.queryByPageCode(pageCode);
if (pageConfig == null) {
context.getPageLog().setSuccess(false);
context.getPageLog().setInfo("page不存在");
context.setShouldSkip(true);
return;
}
//将页面配置设置到上下文中
context.setPageConfig(pageConfig);
context.getPageLog().setTemplateId(pageConfig.getTemplateId());
//发送Event到第二个channel的WorkEventBus里，通过bossEventBus进行中转
bossEventBus.publish(CHANNEL_02_DOWNLOAD_TEMPLATE_FILE, EVENT_02, context);
log.info("第1步：加载页面配置, pageConfig={}", JSON.toJSONString(pageConfig, true));
};
//将封装好的任务，提交到线程池进行执行
executorService.execute(CHANNEL_01_LOAD_PAGE_CONFIG, task);
}
}
public class ExecutorService {
private static final ConcurrentHashMap<String, SafeThreadPool> BUFFER = new ConcurrentHashMap<>();
public ExecutorService(ExecutorConfig executorConfig) {
for (ExecutorConfig.Config config : executorConfig.getExecutors()) {
BUFFER.put(config.getThreadPool(), new SafeThreadPool(config.getThreadPool(), config.getThreadCount()));
}
}
public void execute(String channel, Runnable task) {
//Optional.ofNullable()方法的作用是将一个可能为null的值包装到Optional容器中
//如果该值为null，则返回一个空的Optional对象，否则返回一个包含该值的Optional对象
//使用Optional.ofNullable()可以有效地避免空指针异常，因为它可以让我们在获取一个可能为null的对象时，先判断该对象是否为空，从而避免出现空指针异常
Optional.ofNullable(BUFFER.get(channel)).ifPresent(safeThreadPool -> safeThreadPool.execute(task));
}
}
public class SafeThreadPool {
private final Semaphore semaphore;
private final ThreadPoolExecutor threadPoolExecutor;
public SafeThreadPool(String name, int permits) {
//设置Semaphore信号量为线程数量
semaphore = new Semaphore(permits);
//根据线程数量封装一个线程池，其中最大线程数量maximum的大小就是线程数量permits * 2
//可以往这个线程池里提交最多maximumPoolSize个任务
threadPoolExecutor = new ThreadPoolExecutor(
0,
permits * 2,
60,
TimeUnit.SECONDS,
new SynchronousQueue<>(),
NamedDaemonThreadFactory.getInstance(name)
);
}
public void execute(Runnable task) {
//每次往这个线程池提交任务时，都需要先获取一个信号量
//所以同一时刻，最多只能提交数量与信号量(线程数量)相同的任务到线程池里
//当有超过线程数量的任务提交时，便会在执行下面的代码"获取信号量"时，被阻塞住
semaphore.acquireUninterruptibly();
//虽然使用了semaphore去限制提交到线程池的线程任务数
//但是极端情况下，还是可能会有(信号量 * 2)个线程任务被提交到线程池
//这种极端情况就是：
//线程任务执行完任务并释放掉信号量时，还没释放自己被线程池回收，其他线程就获取到信号量提交到线程池了
threadPoolExecutor.submit(() -> {
try {
//执行任务
task.run();
} finally {
//释放信号量
semaphore.release();
}
//某线程执行到这里时，还没完全把自己释放出来，但信号量已释放，可能新的任务已经加入线程池
});
}
}
(5)页面渲染第二步—下载页面模版
其实就是从Redis中获取页面模版文件。
@Component
@Channel(CHANNEL_02_DOWNLOAD_TEMPLATE_FILE)
public class Event02Listener extends BaseRenderPageListener<Event02DownloadTemplateFile> {
@Autowired
private FileService fileService;
@Override
public boolean accept(BaseEvent event) {
return event instanceof Event02DownloadTemplateFile;
}
//页面渲染第二步：下载页面模板文件
@Override
protected void doThisStep(Event02DownloadTemplateFile event, PageRenderContext context) {
Runnable task = () -> {
//从Redis中获取页面模版文件
String templateContent = fileService.download(context.getPageConfig().getTemplateUrl());
if (Objects.isNull(templateContent)) {
context.getPageLog().setSuccess(false);
context.getPageLog().setInfo("模板文件不存在");
context.setShouldSkip(true);
return;
}
//将页面模板设置到上下文中
context.setTemplateContent(templateContent);
bossEventBus.publish(CHANNEL_03_AGGR_DATA, EVENT_03, context);
log.info("第2步：下载页面模板文件");
};
//提交任务task给线程池执行
executorService.execute(CHANNEL_02_DOWNLOAD_TEMPLATE_FILE, task);
}
}
@Service
public class FileServiceImpl implements FileService {
//缓存的是：模版文件内容、渲染好的HTML静态页面的内容
private final Cache<String, String> cache = CacheBuilder.newBuilder()
.maximumSize(100)
.expireAfterWrite(30, TimeUnit.MINUTES)
.build();
//这里会把页面模板文件、渲染好的HTML静态页面保存到Redis上
@Autowired
private CacheSupport cacheSupport;
public String download(String url) {
try {
//为了简便，下载页面模版文件或下载渲染好的HTML静态页面，其实就是从Redis从获取数据
//页面模板文件、渲染好的HTML静态页面，可以放在某个服务器的文件里，也可以放在阿里云的OSS文件存储中
return cache.get(url, () -> cacheSupport.get(url));
} catch (ExecutionException e) {
e.printStackTrace();
return null;
}
}
public String upload(String content) {
String url = UUID.randomUUID().toString();
//上传页面，就是把页面内容存放到Redis里
cacheSupport.set(url, content);
return url;
}
}
(6)页面渲染第三步—聚合数据
@Component
@Channel(CHANNEL_03_AGGR_DATA)
public class Event03Listener extends BaseRenderPageListener<Event03GetAggrData> {
@Autowired
private RestTemplate restTemplate;
@Override
public boolean accept(BaseEvent event) {
return event instanceof Event03GetAggrData;
}
//页面渲染第二步：调用dataUrl获取聚合数据
@Override
protected void doThisStep(Event03GetAggrData event, PageRenderContext context) {
Runnable task = () -> {
//此时上下文中已经有了页面模板的html字符串，需要继续获取这个页面模板需要的数据
//首先从页面配置中取出可以获取聚合数据的url地址
//然后再基于restTemplate发起HTTP请求，请求页面聚合服务的地址，拉取需要的数据
String aggrDataUrl = context.getPageConfig().getAggrDataUrl();
Map params = context.getParams();
Map map = restTemplate.postForObject(aggrDataUrl, params, Map.class);
if (MapUtils.isEmpty(map)) {
context.getPageLog().setSuccess(false);
context.getPageLog().setInfo("聚合数据有问题");
context.setShouldSkip(true);
return;
}
//将聚合数据设置到上下文中
context.setAggrData(map);
bossEventBus.publish(CHANNEL_04_RENDER_PAGE, EVENT_04, context);
log.info("第3步：调用dataUrl获取聚合数据，aggrData={}", JSON.toJSONString(map, true));
};
executorService.execute(CHANNEL_03_AGGR_DATA, task);
}
}
@RestController
public class SeckillProductAggrController {
@Autowired
private ProductApi productApi;
//获取聚合数据
@PostMapping("/seckill/product")
public Map aggr(@RequestBody Map params) {
Long skuId = Long.parseLong(String.valueOf(params.get("skuId")));
//根据商品系统提供的接口，查询sku数据及其对应的商品spu数据
SkuVo skuVo = productApi.queryBySkuId(skuId);
SpuVo spuVo = productApi.queryBySpuId(skuVo.getSpuId());
Map aggrData = new LinkedHashMap();
aggrData.put("brandId", spuVo.getBrandId());
aggrData.put("brandName", spuVo.getBrandName());
aggrData.put("brandLogo", spuVo.getBrandLogo());
aggrData.put("categoryId", spuVo.getCategoryId());
aggrData.put("categoryName", spuVo.getCategoryName());
aggrData.put("skuId", skuVo.getId());
aggrData.put("skuName", skuVo.getName());
aggrData.put("price", skuVo.getPrice());
aggrData.put("seckillPrice", skuVo.getSeckillPrice());
aggrData.put("image", skuVo.getImage());//缩略图
String[] images = skuVo.getImages().split(",");//images，图文详情里可以有很多图片
for (int i = 0; i < images.length; i++) {
String image = images[i];
aggrData.put("image" + i, image);
}
return aggrData;
}
}
(7)页面渲染第四步—渲染页面
@Component
@Channel(CHANNEL_04_RENDER_PAGE)
public class Event04Listener extends BaseRenderPageListener<Event04RenderPage> {
public boolean accept(BaseEvent event) {
return event instanceof Event04RenderPage;
}
//页面渲染第四步：根据"页面模板 + 聚合数据"渲染页面
//其中的页面模版是基于FreeMarker语法写的HTML静态文件，模版文件中会加入很多FreeMarker语法的占位符(${dd})
//渲染页面时就是基于FreeMarker模板引擎的API，把这些${dd}占位符替换成对应的聚合数据
@Override
protected void doThisStep(Event04RenderPage event, PageRenderContext context) {
Runnable task = () -> {
Map<String, Object> mapData = new HashMap<>(1);
mapData.put("data", context.getAggrData());
String staticPageFile;
try {
String key = "template";
//创建一个FreeMarker的Configuration配置对象
Configuration configuration = new Configuration(Configuration.DEFAULT_INCOMPATIBLE_IMPROVEMENTS);
//创建一个字符串模板类型的Loader对象
StringTemplateLoader stringTemplateLoader = new StringTemplateLoader();
//将上下文中的页面模板数据放到Loader对象中
stringTemplateLoader.putTemplate(key, context.getTemplateContent());
//将Loader对象放入到Configuration配置对象中
configuration.setTemplateLoader(stringTemplateLoader);
//获取一个Template模板对象
Template template = configuration.getTemplate(key);
//FreeMarkerTemplateUtils工具类，会用提供的聚合数据，将页面模板里的占位符进行替换，最后成为一个HTML静态页面的字符串
staticPageFile = FreeMarkerTemplateUtils.processTemplateIntoString(template, mapData);
} catch (Exception e) {
context.getPageLog().setSuccess(false);
context.getPageLog().setInfo("根据页面模板+聚合数据渲染页面时出现问题");
context.setShouldSkip(true);
return;
}
//将HTML静态页面字符串设置到上下文中
context.setStaticPageContent(staticPageFile);
bossEventBus.publish(CHANNEL_05_UPLOAD_STATIC_PAGE, EVENT_05, context);
log.info("第4步：渲染页面");
};
executorService.execute(CHANNEL_04_RENDER_PAGE, task);
}
}
(8)页面渲染第五步—上传静态化页面
其实就是将静态页面HTML字符串存放到Redis中。
@Component
@Channel(CHANNEL_05_UPLOAD_STATIC_PAGE)
public class Event05Listener extends BaseRenderPageListener<Event05UploadStaticPage> {
@Autowired
private FileService fileService;
@Override
public boolean accept(BaseEvent event) {
return event instanceof Event05UploadStaticPage;
}
//页面渲染第五步：上传渲染好的HTML静态页面
@Override
protected void doThisStep(Event05UploadStaticPage event, PageRenderContext context) {
Runnable task = () -> {
//将静态页面HTML字符串存放到Redis中
String setStaticPageId = fileService.upload(context.getStaticPageContent());
if (setStaticPageId == null) {
context.getPageLog().setSuccess(false);
context.getPageLog().setInfo("上传html文件出现问题");
context.setShouldSkip(true);
return;
}
context.setStaticPageId(setStaticPageId);
context.getPageLog().setStaticPageId(setStaticPageId);
context.getPageLog().setCompletionTime(System.currentTimeMillis());
log.info("第5步：上传渲染好的HTML静态页面，url={}", setStaticPageId);
bossEventBus.publish(CHANNEL_06_SAVE_PAGE_LOG_MESSAGE, EVENT_06, context);
};
executorService.execute(CHANNEL_05_UPLOAD_STATIC_PAGE, task);
}
}
@Service
public class FileServiceImpl implements FileService {
//缓存的是：模版文件内容、渲染好的HTML静态页面的内容
private final Cache<String, String> cache = CacheBuilder.newBuilder()
.maximumSize(100)
.expireAfterWrite(30, TimeUnit.MINUTES)
.build();
//这里会把页面模板文件、渲染好的HTML静态页面保存到Redis上
@Autowired
private CacheSupport cacheSupport;
public String download(String url) {
try {
//为了简便，下载页面模版文件或下载渲染好的HTML静态页面，其实就是从Redis从获取数据
//页面模板文件、渲染好的HTML静态页面，可以放在某个服务器的文件里，也可以放在阿里云的OSS文件存储中
return cache.get(url, () -> cacheSupport.get(url));
} catch (ExecutionException e) {
e.printStackTrace();
return null;
}
}
public String upload(String content) {
String url = UUID.randomUUID().toString();
//上传页面，就是把页面内容存放到Redis里
cacheSupport.set(url, content);
return url;
}
}
(9)页面渲染第六步—保存页面渲染日志
@Component
@Channel(CHANNEL_06_SAVE_PAGE_LOG_MESSAGE)
public class Event06Listener extends BaseRenderPageListener<Event06SavePageLog> {
@Autowired
private PageLogService pageLogService;
@Override
public boolean accept(BaseEvent event) {
return event instanceof Event06SavePageLog;
}
//页面渲染第六步：保存页面渲染日志
@Override
protected void doThisStep(Event06SavePageLog event, PageRenderContext context) {
Runnable task = () -> {
String staticPagePath = FilePathUtils.generateFilePath(context.getFileName());
//设置存放静态页面的路径地址
context.setStaticPagePath(staticPagePath);
PageLog pageLog = context.getPageLog();
pageLog.setStaticPageUrl(staticPagePath);
pageLog.setCreateTime(new Date());
pageLog.setUpdateTime(pageLog.getCreateTime());
pageLog.setSuccess(true);
//把本次静态化页面的log写入到数据库
pageLogService.save(pageLog);
log.info("第6步：保存页面渲染日志，pageLog={}", JSON.toJSONString(pageLog, true));
bossEventBus.publish(CHANNEL_07_SEND_PUBLISH_MESSAGE, EVENT_07, context);
};
executorService.execute(CHANNEL_06_SAVE_PAGE_LOG_MESSAGE, task);
}
}
(10)页面渲染第七步—发送渲染成功的消息到MQ
@Component
@Channel(CHANNEL_07_SEND_PUBLISH_MESSAGE)
public class Event07Listener extends BaseRenderPageListener<Event07SendPublishPageMessage> {
@Autowired
private RocketMQTemplate rocketMQTemplate;
@Override
public boolean accept(BaseEvent event) {
return event instanceof Event07SendPublishPageMessage;
}
//页面渲染第七步：发送页面渲染成功的消息到MQ
@Override
protected void doThisStep(Event07SendPublishPageMessage event, PageRenderContext context) {
Runnable task = () -> {
String publishPageMessage = PagePublishMessage.builder()
.pageLogId(context.getPageLog().getId())
.staticPageId(context.getStaticPageId())
.staticPagePath(context.getStaticPagePath())
.build()
.toJsonString();
rocketMQTemplate.syncSend(QueueKey.QUEUE_PUBLISH_PAGE, publishPageMessage);
log.info("第7步：发送页面渲染成功的消息到MQ, message={}", publishPageMessage);
};
executorService.execute(CHANNEL_07_SEND_PUBLISH_MESSAGE, task);
}
}
12.秒杀系统的页面发布服务实现
(1)消费页面渲染成功的消息
(2)发布页面第一步—从Redis加载静态页面
(3)发布页面第二步—将静态页面写到磁盘上
(4)发布页面第三步—发送页面发布完成的消息
(5)发布页面第四步—清除Redis的静态页面
(1)消费页面渲染成功的消息
@Component
@RocketMQMessageListener(topic = QueueKey.QUEUE_PUBLISH_PAGE, consumerGroup = "publishPageGroup", messageModel = MessageModel.BROADCASTING)
public class PublishPageListener implements RocketMQListener<String> {
@Autowired
private BossEventBus bossEventBus;
//消息格式示例
//.pageLogId(context.getPageLog().getId())
//.staticPageUrl(context.getStaticPageUrl())
//.staticPagePath(staticPagePath)
@Override
public void onMessage(String messageString) {
log.info("收到页面渲染成功的消息, message={}", messageString);
JSONObject message = JSONObject.parseObject(messageString);
DownloadEvent event = new DownloadEvent();
event.setPageLogId(message.getLong("pageLogId"));
event.setStaticPageId(message.getString("staticPageId"));
event.setStaticPagePath(message.getString("staticPagePath"));
//发布页面的步骤：
//从Redis加载渲染好的静态页面 -> 将静态页面写到磁盘上 -> 发送页面发布完成的消息 -> 清除Redis的静态页面
bossEventBus.publish(ChannelKey.CHANNEL_DOWNLOAD, event, null);
}
}
(2)发布页面第一步—从Redis加载静态页面
@Component
@Channel(ChannelKey.CHANNEL_DOWNLOAD)
public class DownloadEventListener implements EventListener<DownloadEvent> {
@Autowired
private BossEventBus bossEventBus;
@Autowired
private ExecutorService executorService;
@Autowired
private CacheSupport cacheSupport;
@Override
public boolean accept(BaseEvent event) {
return event instanceof DownloadEvent;
}
//第一步：从Redis上下载已经渲染好的静态页面
@Override
public void onEvent(DownloadEvent event, AsyncContext eventContext) {
executorService.execute(ChannelKey.CHANNEL_DOWNLOAD, () -> {
String staticPageContent = cacheSupport.get(event.getStaticPageId());
log.info("第1步：下载页面, event={}", JSON.toJSONString(event));
WriteToDiskEvent e = new WriteToDiskEvent();
e.setPageLogId(event.getPageLogId());
e.setStaticPageId(event.getStaticPageId());
e.setStaticPagePath(event.getStaticPagePath());
e.setStaticPageContent(staticPageContent);
bossEventBus.publish(ChannelKey.CHANNEL_WRITE_TO_DISK, e, null);
});
}
}
(3)发布页面第二步—将静态页面写到磁盘上
@Component
@Channel(ChannelKey.CHANNEL_WRITE_TO_DISK)
public class WriteToDiskEventListener implements EventListener<WriteToDiskEvent> {
@Autowired
private BossEventBus bossEventBus;
@Autowired
private ExecutorService executorService;
@Override
public boolean accept(BaseEvent event) {
return event instanceof WriteToDiskEvent;
}
//第二步：将下载的已渲染的静态页面写到磁盘上
@Override
public void onEvent(WriteToDiskEvent event, AsyncContext eventContext) {
executorService.execute(ChannelKey.CHANNEL_WRITE_TO_DISK, () -> {
String staticPagePath = event.getStaticPagePath();
String staticPageContent = event.getStaticPageContent();
boolean success = true;
//确保目录存在
String parentDir = FilePathUtils.getParentDir(staticPagePath);
File parent = new File(parentDir);
if (!parent.exists()) {
success = parent.mkdirs();
}
if (success) {
//把页面的内容写到文件中
File file = new File(staticPagePath);
try (RandomAccessFile raf = new RandomAccessFile(file, "rw")) {
raf.write(staticPageContent.getBytes());
} catch (IOException e) {
e.printStackTrace();
success = false;
}
}
log.info("第2步：把静态页面写到磁盘上, event={}", JSON.toJSONString(event));
PulishResultEvent e = new PulishResultEvent();
e.setPageLogId(event.getPageLogId());
e.setStaticPageId(event.getStaticPageId());
e.setSuccess(success);
//这里只是演示把文件写入本地的磁盘里
//当然也可以通过执行scp命令，把写入磁盘的静态页面html文件上传到Nginx服务器指定的目录中
//然后调用的CDN厂商的API，把页面数据预热和加载到CDN
bossEventBus.publish(ChannelKey.CHANNEL_PUBLISH_RESULT, e, null);
});
}
}
(4)发布页面第三步—发送页面发布完成的消息
@Component
@Channel(ChannelKey.CHANNEL_PUBLISH_RESULT)
public class PublishResultEventListener implements EventListener<PulishResultEvent> {
@Autowired
private BossEventBus bossEventBus;
@Autowired
private ExecutorService executorService;
@Autowired
private RocketMQTemplate rocketMQTemplate;
@Override
public boolean accept(BaseEvent event) {
return event instanceof PulishResultEvent;
}
//第三步：发送页面发布完成的消息到MQ
@Override
public void onEvent(PulishResultEvent event, AsyncContext eventContext) {
executorService.execute(ChannelKey.CHANNEL_PUBLISH_RESULT, () -> {
String message = PagePublishResultMessage.builder()
.pageLogId(event.getPageLogId())
.success(event.isSuccess())
.serverIp(BusinessConfig.getMyIp())
.build().toJsonString();
rocketMQTemplate.syncSend(QueueKey.QUEUE_PUBLISH_PAGE_RESULT, message);
log.info("第3步：发送页面发布完成的消息到MQ, message={}", message);
RemoveStaticPageEvent e = new RemoveStaticPageEvent();
e.setStaticPageId(event.getStaticPageId());
bossEventBus.publish(ChannelKey.CHANNEL_REMOVE_STATIC_PAGE, e, null);
});
}
}
@Component
@RocketMQMessageListener(topic = QueueKey.QUEUE_PUBLISH_PAGE_RESULT, consumerGroup = "publishPageResultGroup")
public class PublishPageResultListener implements RocketMQListener<String> {
@Autowired
private PageLogService pageLogService;
@Autowired
private RocketMQTemplate rocketMQTemplate;
//消息格式示例
//.pageLogId(event.getPageLogId())
//.success(event.isSuccess())
//.serverIp(BussinessConfig.getMyIp())
@Override
public void onMessage(String messageString) {
log.info("收到页面发布完成的消息, message={}", messageString);
JSONObject message = JSONObject.parseObject(messageString);
Long pageLogId = message.getLong("pageLogId");
Boolean success = message.getBoolean("success");
String serverIp = message.getString("serverIp");
PageLog pageLog = pageLogService.queryById(pageLogId);
if (!success) {
log.error("{}发布{}页面失败", serverIp, pageLog.getFileName());
return;
}
String lastestFinshedServerIps;
String finishedServerIps = pageLog.getFinishedServerIps();
if (finishedServerIps == null) {
lastestFinshedServerIps = serverIp;
} else {
lastestFinshedServerIps = finishedServerIps + "," + serverIp;
}
List<String> list = Arrays.asList(lastestFinshedServerIps.split(","));
list.sort(Comparator.comparing(e -> e));
lastestFinshedServerIps = String.join(",", list);
pageLogService.updateFinishedServerIps(pageLogId, lastestFinshedServerIps);
log.info("收到页面发布的结果, 修改流水的FinishedServerIps字段");
if (StringUtils.equals(pageLog.getServerIps(), lastestFinshedServerIps)) {
String msg = PageRenderResultMessage.builder().bizData(JSON.parseObject(pageLog.getBizData())).success(true).build().toJsonString();
rocketMQTemplate.convertAndSend(QueueKey.QUEUE_RENDER_PAGE_RESULT, msg);
log.info("收到页面发布完成的消息, 检查发现页面已发布到所有的静态资源服务器上，发送页面渲染结果的消息，可以开始同步库存, message={}", msg);
}
}
}
//消费渲染页面结果的消息(每渲染和发布完一个页面就会发送一条页面渲染结果的消息)
@Component
@RocketMQMessageListener(topic = QueueKey.QUEUE_RENDER_PAGE_RESULT, consumerGroup = "pageResultGroup")
public class PageResultListener implements RocketMQListener<String> {
@Autowired
private ActivityService activityService;
@Autowired
private ActivitySkuRefService activitySkuRefService;
@Override
public void onMessage(String messageString) {
log.info("收到渲染页面的结果, message={}", messageString);
JSONObject message = JSONObject.parseObject(messageString);
if (!message.getBoolean("success")) {
log.error("页面渲染失败，需要及时查看问题");
return;
}
//获取指定的bizData
//渲染秒杀活动列表页时指定的bizData如下：
//.bizData(ImmutableMap.of("type", "activity", "activityId", activity.getId()))
//渲染秒杀商品详情页时指定的bizData如下：
//.bizData(ImmutableMap.of("type", "product", "activityId", activity.getId(), "skuId", activitySkuRef.getSkuId()))
JSONObject bizData = message.getJSONObject("bizData");
String type = bizData.getString("type");
Long activityId = bizData.getLong("activityId");
//判断本次渲染成功的页面，是活动列表页还是商品详情页
if (StringUtils.equals(type, "activity")) {
activityService.updatePageReady(activityId, true);
log.info("收到渲染页面的结果, 是活动页面的结果, 把活动的pageReady字段修改为true");
} else if (StringUtils.equals(type, "product")) {
activitySkuRefService.updatePageReady(activityId, bizData.getLong("skuId"), true);
log.info("收到渲染页面的结果, 是商品页面的结果, 把商品的pageReady字段修改为true");
}
//判断当前活动是否所有的静态页面都渲染好了
Activity activity = activityService.queryById(activityId);
//count一下该秒杀活动下还没渲染完成的商品数量
Integer count = activitySkuRefService.countByActivityIdAndPageReady(activityId, false);
//当秒杀活动的页面已渲染成功 + 秒杀活动的所有商品详情页也渲染成功，则更新秒杀活动的状态为'页面已完成渲染'
if (activity.getPageReady() && count == 0) {
//更新该秒杀活动的状态，从"页面渲染中"到"页面已完成渲染"
activityService.updateStatus(activityId, ActivityStatusVal.PAGE_RENDERING.getCode(), ActivityStatusVal.PAGE_RENDERED.getCode());
log.info("收到渲染页面的结果, 检查后发现当前活动的活动页面和商品页面都渲染好了，把活动状态改为'页面已渲染'");
//下一步就是同步库存到Redis，进行库存数据的初始化了
//触发执行库存数据初始化的定时任务的两个条件：
//1.秒杀活动的所有页面已渲染完毕 + 2.now距离showTime在1小时以内
}
}
}
//库存分片和同步库存
@Component
public class TriggerStockTask {
@Autowired
private ActivityService activityService;
@Autowired
private ActivitySkuRefService activitySkuRefService;
@Autowired
private LockService lockService;
@Autowired
private InventoryApi inventoryApi;
@Scheduled(fixedDelay = 10_000)
public void run() {
String lockToken = lockService.tryLock(CacheKey.TRIGGER_STOCK_LOCK, 1, TimeUnit.SECONDS);
if (lockToken == null) {
return;
}
log.info("触发库存分片和同步库存，获取分布式锁成功, lockToken={}", lockToken);
try {
//查询已经渲染好页面的所有秒杀活动
List<Activity> activities = activityService.queryListForTriggerStockTask();
if (CollectionUtils.isEmpty(activities)) {
return;
}
for (Activity activity : activities) {
List<ActivitySkuRef> activitySkuRefs = activitySkuRefService.queryByActivityId(activity.getId());
if (CollectionUtils.isEmpty(activitySkuRefs)) {
continue;
}
//要进行缓存初始化的商品，封装库存初始化请求
List<SyncProductStockRequest> request = new ArrayList<>();
for (ActivitySkuRef activitySkuRef : activitySkuRefs) {
SyncProductStockRequest syncProductStockRequest = SyncProductStockRequest.builder()
.activityId(activitySkuRef.getActivityId())
.skuId(activitySkuRef.getSkuId())
.seckillStock(activitySkuRef.getSeckillStock()).build();
request.add(syncProductStockRequest);
}
//把封装的库存初始化请求，发送到秒杀库存服务里
//每个商品的库存数据都会分散到各个Redis节点上去，实现对商品库存分片存放
if (inventoryApi.syncStock(request)) {
log.info("触发库存分片和同步库存，调用库存接口将商品库存同步到Redis");
activityService.updateStatus(activity.getId(), ActivityStatusVal.PAGE_RENDERED.getCode(), ActivityStatusVal.INVENTORY_SYNCED.getCode());
log.info("触发库存分片和同步库存，将秒杀活动的状态修改为库存已同步");
//完成库存分片后，用户就可以对商品发起秒杀抢购了
} else {
log.error("触发库存分片和同步库存，库存同步失败");
}
}
} finally {
lockService.release(CacheKey.TRIGGER_STOCK_LOCK, lockToken);
log.info("触发库存分片和同步库存，释放分布式锁");
}
}
}
(5)发布页面第四步—清除Redis的静态页面
@Component
@Channel(ChannelKey.CHANNEL_REMOVE_STATIC_PAGE)
public class RemoveStaticPageEventListener implements EventListener<RemoveStaticPageEvent> {
@Autowired
private ExecutorService executorService;
@Autowired
private CacheSupport cacheSupport;
@Override
public boolean accept(BaseEvent event) {
return event instanceof RemoveStaticPageEvent;
}
//第四步：删除Redis上的静态页面
@Override
public void onEvent(RemoveStaticPageEvent event, AsyncContext eventContext) {
executorService.execute(ChannelKey.CHANNEL_REMOVE_STATIC_PAGE, () -> {
cacheSupport.del(event.getStaticPageId());
log.info("第4步，删除Redis上的静态页面");
});
}
}
后端技术栈的基础修养 文章被收录于专栏
详细介绍后端技术栈的基础内容，包括但不限于：MySQL原理和优化、Redis原理和应用、JVM和G1原理和优化、RocketMQ原理应用及源码、Kafka原理应用及源码、ElasticSearch原理应用及源码、JUC源码、Netty源码、zk源码、Dubbo源码、Spring源码、Spring Boot源码、SCA源码、分布式锁源码、分布式事务、分库分表和TiDB、大型商品系统、大型订单系统等
