mongodb scala驅動程序 - 無法檢索文檔

Question

我無法使用新的scala驅動程序在mongoDB中檢索文檔。

這裏我的代碼：

def retrieveDocument(id: Int, 
     collectionName: String, 
     databaseName: String, 
     url: String): Option[Document] = { 
var res: Option[Document] = None 
getMongoCollectionImmutable(collectionName, databaseName, url) 
    .find(Filters.equal("_id", id)) 
    .first().subscribe(
    (doc: Document) => res = Some(doc), 
    (e: Throwable) => throw e, 
() =>()) 
res 
} 

def getMongoCollectionImmutable(collectionName: String, 
     databaseName: String, 
     url: String = DEFAULT_URL): MongoCollection[ImmuDoc] = { 
db match { 
    case None => 
    getMongoDatabase(databaseName, url).getCollection(collectionName) 
    case Some(db) => 
    db.client.getDatabase(databaseName).getCollection(collectionName) 
} 

def getMongoDatabase(name: String, url: String = DEFAULT_URL): MongoDatabase = { 
db match { 
    case None => 
    db = Some(new _Database(url)) 
    getMongoDatabase(name) 
    case Some(db) => 
    db.client.getDatabase(name) 
} 

def retrieve(id: Int): Try[User] = { 
try { 
    val docOption = Database.retrieveDocument(id, USER_COLLECTION, DATABASE_NAME, DEFAULT_URL) 
    docOption match { 
    case None  => Failure(new Exception(s"Unable to retrieve a user with id ${id}")) 
    case Some(doc) => Try(User(doc)) 
    } 
} catch { 
    case e: Throwable => Failure(e) 
} 

}

這裏是驅動程序的（顯著）日誌：

19:16:24.334 DEBUG cluster - Updating cluster description to {type=STANDALONE, servers=[{address=localhost:27017, type=STANDALONE, roundTripTime=0.7 ms, state=CONNECTED}] 
19:16:24.366 INFO connection - Opened connection [connectionId{localValue:2, serverValue:90}] to localhost:27017 
19:16:24.377 DEBUG query - Asynchronously sending query of namespace jobless.user on connection [connectionId{localValue:2, serverValue:90}] to server localhost:27017 
19:16:24.381 DEBUG query - Query results received 1 documents with cursor null 

這裏我的測試輸出

Run starting. Expected test count is: 1 
UserTest: 
User Document((_id,BsonInt32{value=1}), (firstname,BsonString{value='user1'}), (lastname,BsonString{value='last1'}), (encryptedPass,BsonString{value='pass'}), (cvListPath,BsonArray{values=[{ "name" : "path1", "path" : "name1" }, { "name" : "path2", "path" : "name2" }]}), (motivationLettersPath,BsonArray{values=[{ "name" : "path1", "path" : "name1" }, { "name" : "path2", "path" : "name2" }]})) 
- retrieve from DB Failure(java.lang.Exception: Unable to retrieve a user with id 1) *** FAILED *** 
    java.lang.Exception: Unable to retrieve a user with id 1 (UserTest.scala:31) 

但！通過使用wireshark，我可以看到正確的數據庫查詢並返回文檔！ （我檢查使用蒙戈linux命令進行查詢的，它是非常相同）

Frame 1262: 123 bytes on wire (984 bits), 123 bytes captured (984 bits) on interface 0 
Linux cooked capture 
Internet Protocol Version 4, Src: 127.0.0.1, Dst: 127.0.0.1 
Transmission Control Protocol, Src Port: 42714, Dst Port: 27017, Seq: 438, Ack: 1272, Len: 55 
Mongo Wire Protocol 
    Message Length: 55 
    Request ID: 0x00000008 (8) 
    Response To: 0x00000000 (0) 
    OpCode: Query (2004) 
    Query Flags 
    fullCollectionName: xxx.user 
    Number To Skip: 0 
    Number to Return: -1 
    Query 
     Document length: 14 
     Elements 
      Element: _id 
       Type: Int32 (0x10) 
       Value: 1 

和數據庫的響應也是正確的。

我在做什麼錯？

Answer 1

好了，所以，我怪我自己（和驅動程序的神祕文檔）

這個驅動是異步的，所以我們只能等待它完成... 所以總結起來使用（發現here），這是真正的文檔中使用無需驅動程序本身

implicit class DocumentObservable[C](val observable: Observable[Document]) extends ImplicitObservable[Document] { 
    override val converter: (Document) => String = (doc) => doc.toJson 
} 

implicit class GenericObservable[C](val observable: Observable[C]) extends ImplicitObservable[C] { 
    override val converter: (C) => String = (doc) => doc.toString 
} 

trait ImplicitObservable[C] { 
    val observable: Observable[C] 
    val converter: (C) => String 

    def results(): Seq[C] = Await.result(observable.toFuture(), Duration(10, TimeUnit.SECONDS)) 
    def headResult() = Await.result(observable.head(), Duration(10, TimeUnit.SECONDS)) 
    def printResults(initial: String = ""): Unit = { 
    if (initial.length > 0) print(initial) 
    results().foreach(res => println(converter(res))) 
    } 
    def printHeadResult(initial: String = ""): Unit = println(s"${initial}${converter(headResult())}") 
} 

正在和不斷變化的檢索方式：

def retrieveDocument(id: Int, collectionName: String, databaseName: String, url: String): Option[Document] = { 
var res: Option[Document] = None 
getMongoCollectionImmutable(collectionName, databaseName, url) 
    .find(Filters.equal("_id", id)) 
    .limit(1).results().foreach({ x => res = Some(x) }) 
res 

}

它修復了我的問題。