从 mongodb 的 id 中获取时间
2025-01-22 08:19:30    221 字    #mongodb
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The automatically generated _id (ObjectId) field in MongoDB stores date information. The timestamp is contained within the first 4 bytes of the _id.

The _id (ObjectId) is a 12-byte BSON data, divided into four parts, where:

  1. The first 4 bytes represent the timestamp.
  2. The next 3 bytes are the machine identifier.
  3. The subsequent two bytes consist of the process id (PID).
  4. The last three bytes are randomly generated by the incremental counter.
mongodb _id

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// ...
org.bson.types.ObjectId objectId = new org.bson.types.ObjectId(infoData.getId());
java.util.Date createTime = objectId.getDate();
// ...


↓↓↓↓↓ 中文 ↓↓↓↓↓

MongoDB 自动生成的 _id(ObjectId) 字段存储了日期的信息。时间戳包含在 _id 的前4个字节中。

_id(ObjectId) 是一个12个字节的BSON数据，分成四个部分，其中：

  1. 前4个字节表示时间戳；
  2. 接下来的3个字节是机器标识码；
  3. 紧接的两个字节由进程id组成（PID）；
  4. 最后三个字节是自增计数器生成的随机数；
mongodb _id

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// ...
org.bson.types.ObjectId objectId = new org.bson.types.ObjectId(infoData.getId());
java.util.Date createTime = objectId.getDate();
// ...