如何克服这个错误"com.mongodb.diagnostics.logging.JULLogger log"

Question

我正在使用与MongoDB连接的java程序。当我运行该程序时，它会显示一个错误，但代码正在工作。MongoDB有一个名为MongoDB的数据库，其中有一个称为seatbooking的集合，包含两列(名称、座位号(。这是我的代码：

MongoClient mongoClient = new MongoClient("localhost", 27017);
System.out.println("connection is established");
MongoDatabase mongoDatabase = mongoClient.getDatabase("MongoDB");
MongoCollection mongoCollection = mongoDatabase.getCollection("seatbooking");
Document document = new Document("name","shenal");
document.append("seatnumber",20);
mongoCollection.insertOne(document);

当我运行此代码时，我的输出是：

> Mar 09, 2020 12:41:36 PM
> com.mongodb.diagnostics.logging.JULLogger log INFO: Cluster created
> with settings {hosts=[localhost:27017], mode=SINGLE,
> requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms',
> maxWaitQueueSize=500}
> **connection is established** Mar 09, 2020 12:41:36 PM com.mongodb.diagnostics.logging.JULLogger log INFO: Cluster
> description not yet available. Waiting for 30000 ms before timing out
> Mar 09, 2020 12:41:36 PM com.mongodb.diagnostics.logging.JULLogger log
> INFO: Opened connection [connectionId{localValue:1, serverValue:309}]
> to localhost:27017 Mar 09, 2020 12:41:36 PM
> com.mongodb.diagnostics.logging.JULLogger log INFO: Monitor thread
> successfully connected to server with description
> ServerDescription{address=localhost:27017, type=STANDALONE,
> state=CONNECTED, ok=true, version=ServerVersion{versionList=[4, 2,
> 2]}, minWireVersion=0, maxWireVersion=8, maxDocumentSize=16777216,
> logicalSessionTimeoutMinutes=30, roundTripTimeNanos=5168100} Mar 09,
> 2020 12:41:36 PM com.mongodb.diagnostics.logging.JULLogger log INFO:
> Opened connection [connectionId{localValue:2, serverValue:310}] to
> localhost:27017

Answer 1

日志输出不显示insertOne操作的任何结果。

如果您使用的是4.0之前的MongoDB Java驱动程序版本，则不会返回确认对象。但是，版本4的insertOne方法返回InsertOneResult对象。这是4.0中的一个新功能(在以前的版本中，该方法返回了void(。

您可以使用以下代码来检查插入的结果，如下所示(对于4.0版(：

try {
InsertOneResult insertResult = collection.insertOne(document);
System.out.println("Document inserted with ID: " + insertResult.getInsertedId());
}
catch(MongoWriteException e) {
// write failure happened, handle it here...
}