blocks|key|975046|text|我刚刚意识到你可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|975047|BasicDBObject+doc+=+new+BasicDBObject(+"name",+"Matt"+);
collection.insert(+doc+);
ObjectId+id+=+(ObjectId)doc.get(+"_id"+);|code-block|syntax|javascript|975048|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I just realized you can do this:

<pre><code>BasicDBObject doc = new BasicDBObject( "name", "Matt" );
collection.insert( doc );
ObjectId id = (ObjectId)doc.get( "_id" );
</code></pre>

blocks|key|975175|text|为了避免在给定com.mongodb.client.MongoCollection+collection和org.bson.Document+doc的情况下从Object转换为ObjectId，您可以执行以下操作：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|975176|collection.insert(doc);
ObjectId+id+=+doc.getObjectId("_id");|code-block|syntax|javascript|975177|entityMap^0|7|19|1H|L|27|6|2G|8|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|L|$]]

To avoid casting from <code>Object</code> to <code>ObjectId</code>, given a <code>com.mongodb.client.MongoCollection collection</code> and a <code>org.bson.Document doc</code>, you can do the following:

<pre><code>collection.insert(doc);
ObjectId id = doc.getObjectId("_id");
</code></pre>

blocks|key|975107|text|这样做是安全的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|975108|doc.set("_id",+new+ObjectId())|code-block|syntax|javascript|975109|如果你看一下驱动程序代码|975110|if+(+ensureID+&&+id+==+null+){
++++id+=+ObjectId.get();
++++jo.put(+"_id"+,+id+);+++++++
}

public+static+ObjectId+get(){
++++return+new+ObjectId();
}|975111|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

It's safe to do 

<pre><code>doc.set("_id", new ObjectId())
</code></pre>

if you look at driver code 

<pre><code>if ( ensureID &amp;&amp; id == null ){
 id = ObjectId.get();
 jo.put( "_id" , id ); 
}

public static ObjectId get(){
 return new ObjectId();
}
</code></pre>

blocks|key|1189228|text|我不知道Java驱动程序，但对于后人来说，可以运行getLastError命令来获取写入的_id，甚至是upsert+(从1.5.4开始)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1189229|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I do not know about the Java driver but for posterity, the getLastError command can be run to get the _id of a write, even an upsert (as of 1.5.4)

blocks|key|1189256|text|将文档插入到MongoDB集合中后，成功的插入应更新必填字段(即，_id)。您可以在插入的对象中查询_id。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1189257|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

After a document is inserted into the MongoDB collection, the successful insertion should update required fields (viz. _id). You may query the inserted object for the _id.

blocks|key|975239|text|在MongoTemplate.class中有一个方法|type|unstyled|depth|inlineStyleRanges|entityRanges|data|975240|protected+<T>+void+doInsert(String+collectionName,+T+objectToSave,+MongoWriter<T>+writer)+{

++++assertUpdateableIdIfNotSet(objectToSave);

++++initializeVersionProperty(objectToSave);

++++maybeEmitEvent(new+BeforeConvertEvent<T>(objectToSave,+collectionName));

++++DBObject+dbDoc+=+toDbObject(objectToSave,+writer);

++++maybeEmitEvent(new+BeforeSaveEvent<T>(objectToSave,+dbDoc,+collectionName));
++++Object+id+=+insertDBObject(collectionName,+dbDoc,+objectToSave.getClass());

++++populateIdIfNecessary(objectToSave,+id);
++++maybeEmitEvent(new+AfterSaveEvent<T>(objectToSave,+dbDoc,+collectionName));
}|code-block|syntax|javascript|975241|该方法将为我们设置id。|975242|protected+void+populateIdIfNecessary(Object+savedObject,+Object+id)+{

++++if+(id+==+null)+{
++++++++return;
++++}

++++if+(savedObject+instanceof+BasicDBObject)+{
++++++++DBObject+dbObject+=+(DBObject)+savedObject;
++++++++dbObject.put(ID_FIELD,+id);
++++++++return;
++++}

++++MongoPersistentProperty+idProp+=+getIdPropertyFor(savedObject.getClass());

++++if+(idProp+==+null)+{
++++++++return;
++++}

++++ConversionService+conversionService+=+mongoConverter.getConversionService();
++++MongoPersistentEntity<?>+entity+=+mappingContext.getPersistentEntity(savedObject.getClass());
++++PersistentPropertyAccessor+accessor+=+entity.getPropertyAccessor(savedObject);

++++if+(accessor.getProperty(idProp)+!=+null)+{
++++++++return;
++++}

++++new+ConvertingPropertyAccessor(accessor,+conversionService).setProperty(idProp,+id);
}|975243|我们可以看到实体是否是BasicDBObject的子类，它将为我们设置一个id。|975244|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

In MongoTemplate.class has a method

<pre><code>protected &lt;T&gt; void doInsert(String collectionName, T objectToSave, MongoWriter&lt;T&gt; writer) {

 assertUpdateableIdIfNotSet(objectToSave);

 initializeVersionProperty(objectToSave);

 maybeEmitEvent(new BeforeConvertEvent&lt;T&gt;(objectToSave, collectionName));

 DBObject dbDoc = toDbObject(objectToSave, writer);

 maybeEmitEvent(new BeforeSaveEvent&lt;T&gt;(objectToSave, dbDoc, collectionName));
 Object id = insertDBObject(collectionName, dbDoc, objectToSave.getClass());

 populateIdIfNecessary(objectToSave, id);
 maybeEmitEvent(new AfterSaveEvent&lt;T&gt;(objectToSave, dbDoc, collectionName));
}
</code></pre>

and the method will set id for us

<pre><code>protected void populateIdIfNecessary(Object savedObject, Object id) {

 if (id == null) {
 return;
 }

 if (savedObject instanceof BasicDBObject) {
 DBObject dbObject = (DBObject) savedObject;
 dbObject.put(ID_FIELD, id);
 return;
 }

 MongoPersistentProperty idProp = getIdPropertyFor(savedObject.getClass());

 if (idProp == null) {
 return;
 }

 ConversionService conversionService = mongoConverter.getConversionService();
 MongoPersistentEntity&lt;?&gt; entity = mappingContext.getPersistentEntity(savedObject.getClass());
 PersistentPropertyAccessor accessor = entity.getPropertyAccessor(savedObject);

 if (accessor.getProperty(idProp) != null) {
 return;
 }

 new ConvertingPropertyAccessor(accessor, conversionService).setProperty(idProp, id);
}
</code></pre>

we can see if the entity is a sub-class of BasicDBObject,it will set a id for us.

blocks|key|1189480|text|我认为这个问题的答案是“不”。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1189481|您可以做的是自己提供_id，或者手动提供，或者实现CollectibleCodec机制(这正是BasicBDDocument所做的)。但是，所有这些解决方案都涉及到客户端ID的生成。|offset|length|style|CODE|1189482|话虽如此，我不认为生成_id客户端有任何问题。|1189483|entityMap^0|0|A|3|P|G|1B|F|0|B|3|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@$D|N|E|O|F|G]|$D|P|E|Q|F|G]|$D|R|E|S|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|T|8|@$D|U|E|V|F|G]]|9|@]|A|$]]|$1|J|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|K|$]]

I think the answer to this is "No". 

What you can do is provide your the <code>_id</code> yourself, either manually, or implement the <code>CollectibleCodec</code> mechanism (which is exactly what <code>BasicBDDocument</code> does). However all these solutions involve generating the ID clientside.

Having said that, I don't think there's any problem with generating the <code>_id</code> clientside.

blocks|key|1189313|text|这是插入操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1189314|DBCollection+table1+=+db.getCollection("Collection+name");
BasicDBObject+document+=+new+BasicDBObject();
document.put("_id",value);++++++
document.put("Name",+name);
table1.insert(document);|code-block|syntax|javascript|1189315|在插入u之后，获取最后插入的id：|1189316|DBCollection+tableDetails+=+db.getCollection("collection+name");
BasicDBObject+queryDetails+=+new+BasicDBObject();
queryDetails.put("_id",+value);
DBCursor+cursorDetails+=tableDetails.find(queryDetails);
DBObject+oneDetails;
oneDetails=cursorDetails.next();++++++++
String+data=oneDetails.get("_id").toString();
System.out.println(data);|1189317|获取值后，将其转换为内部类型。|1189318|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

This is insert operation:

<pre><code>DBCollection table1 = db.getCollection("Collection name");
BasicDBObject document = new BasicDBObject();
document.put("_id",value); 
document.put("Name", name);
table1.insert(document);
</code></pre>

After insert u get last inserted id:

<pre><code>DBCollection tableDetails = db.getCollection("collection name");
BasicDBObject queryDetails = new BasicDBObject();
queryDetails.put("_id", value);
DBCursor cursorDetails =tableDetails.find(queryDetails);
DBObject oneDetails;
oneDetails=cursorDetails.next(); 
String data=oneDetails.get("_id").toString();
System.out.println(data);
</code></pre>

after getting value convert to inter type.

Is there an easy way to get the ID (ObjectID) of the last inserted document of a mongoDB instance using the Java driver?

Get ID of last inserted document in a mongoDB w/ Java driver

MongoDB

Java

有没有一种简单的方法来获得mongoDB实例最后插入的文档的ID (ObjectID)？

问获取mongoDB驱动程序中最后插入的文档的ID
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问获取mongoDB驱动程序中最后插入的文档的IDEN

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问获取mongoDB驱动程序中最后插入的文档的ID
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