3、消息存储实现消息存储实现，比较复杂，也值得大家深入了解，后面会单独成文来分析，这小节只以代码说明一下具体的流程。
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// Set the storage timemsg.setStoreTimestamp(System.currentTimeMillis());// Set the message body BODY CRC (consider the most appropriate settingmsg.setBodyCRC(UtilAll.crc32(msg.getBody()));StoreStatsService storeStatsService = this.defaultMessageStore.getStoreStatsService();synchronized (this) { long beginLockTimestamp = this.defaultMessageStore.getSystemClock().now(); // Here settings are stored timestamp, in order to ensure an orderly global msg.setStoreTimestamp(beginLockTimestamp); // MapedFile：操作物理文件在内存中的映射以及将内存数据持久化到物理文件中 MapedFile mapedFile = this.mapedFileQueue.getLastMapedFile(); // 将Message追加到文件commitlog result = mapedFile.appendMessage(msg, this.appendMessageCallback); switch (result.getStatus()) { case PUT_OK:break; case END_OF_FILE: // Create a new file, re-write the message mapedFile = this.mapedFileQueue.getLastMapedFile(); result = mapedFile.appendMessage(msg, this.appendMessageCallback); break; DispatchRequest dispatchRequest = new DispatchRequest( topic,// 1 queueId,// 2 result.getWroteOffset(),// 3 result.getWroteBytes(),// 4 tagsCode,// 5 msg.getStoreTimestamp(),// 6 result.getLogicsOffset(),// 7 msg.getKeys(),// 8 /** * Transaction */ msg.getSysFlag(),// 9 msg.getPreparedTransactionOffset());// 10 // 1.分发消息位置到ConsumeQueue // 2.分发到IndexService建立索引 this.defaultMessageStore.putDispatchRequest(dispatchRequest);}[url=][/url]
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