如何避免異常使用 mongoDB Java 驅動程序 3.4+ 或 3.6+ 過早到達 stream 的結尾？ （插入時）

Question

我正在嘗試使用這段代碼將一些文檔插入到上限集合中：

            // get document with specific fields
            Document found = collection.find().first();
            String getTitle = (String) found.get("title");
            String getUrl = (String) found.get("url");
            String getImg = (String) found.get("img");
            String getPrice = (String) found.get("price");

            // document which I want to get as new
            Document doc = collection.find(new Document("title", getTitle)
                    .append("url", getUrl)
                    .append("img", getImg)
                    .append("price", getPrice)
                    .append("sent", true)).first();

            // if the document doesn't exist, then insert as new
            if (doc == null) {
             collection.insertOne(new Document("title", getTitle)
                   .append("url", getUrl)
                   .append("img", getImg)
                   .append("price", getPrice)
                   .append("sent", true));
        }

這意味着 - 重寫文件。 我插入的新文檔多了一個字段，而不是舊文檔，因為上限集合不允許用另一種大小更新現有文檔。 因為我得到一個例外： Cannot change the size of a document in a capped collection 。

舊文檔看起來像：

新的將是：

這段代碼工作正常，但過了一會兒（插入期間）我不斷收到錯誤消息：

com.mongodb.MongoSocketReadException: Prematurely reached end of stream
    at com.mongodb.connection.SocketStream.read(SocketStream.java:88)
    at com.mongodb.connection.InternalStreamConnection.receiveResponseBuffers(InternalStreamConnection.java:491)
    at com.mongodb.connection.InternalStreamConnection.receiveMessage(InternalStreamConnection.java:221)
    at com.mongodb.connection.CommandHelper.receiveReply(CommandHelper.java:134)
    at com.mongodb.connection.CommandHelper.receiveCommandResult(CommandHelper.java:121)
    at com.mongodb.connection.CommandHelper.executeCommand(CommandHelper.java:32)
    at com.mongodb.connection.InternalStreamConnectionInitializer.initializeConnectionDescription(InternalStreamConnectionInitializer.java:83)
    at com.mongodb.connection.InternalStreamConnectionInitializer.initialize(InternalStreamConnectionInitializer.java:43)
    at com.mongodb.connection.InternalStreamConnection.open(InternalStreamConnection.java:115)
    at com.mongodb.connection.UsageTrackingInternalConnection.open(UsageTrackingInternalConnection.java:46)
    at com.mongodb.connection.DefaultConnectionPool$PooledConnection.open(DefaultConnectionPool.java:381)
    at com.mongodb.connection.DefaultConnectionPool.get(DefaultConnectionPool.java:96)
    at com.mongodb.connection.DefaultConnectionPool.get(DefaultConnectionPool.java:82)
    at com.mongodb.connection.DefaultServer.getConnection(DefaultServer.java:72)
    at com.mongodb.binding.ClusterBinding$ClusterBindingConnectionSource.getConnection(ClusterBinding.java:86)
    at com.mongodb.operation.OperationHelper.withConnectionSource(OperationHelper.java:237)
    at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:212)
    at com.mongodb.operation.FindOperation.execute(FindOperation.java:482)
    at com.mongodb.operation.FindOperation.execute(FindOperation.java:79)
    at com.mongodb.Mongo.execute(Mongo.java:772)
    at com.mongodb.Mongo$2.execute(Mongo.java:759)
    at com.mongodb.FindIterableImpl$FindOperationIterable.first(FindIterableImpl.java:207)
    at com.mongodb.FindIterableImpl.first(FindIterableImpl.java:148)
    at project.Bot.onUpdateReceived(Bot.java:347)

據我正確理解，錯誤出現在行上（可能只是格式問題）：

 Document found = collection.find().first();

我研究並嘗試使用此代碼解決錯誤（我正在使用免費的 M0 層集群）：

  MongoCredential credential = MongoCredential.createCredential("admin1", "admin", "mypassword".toCharArray());
        MongoClientSettings settings = MongoClientSettings.builder()
                .credential(credential)
                .retryWrites(true)
                .applyToConnectionPoolSettings(builder ->
                        builder.maxConnectionIdleTime(60000, TimeUnit.MILLISECONDS))
                .applyToSocketSettings(builder ->
                        builder.keepAlive(true))
                .applyToSslSettings(builder -> builder.enabled(true))
                .applyToClusterSettings(builder -> {
                    builder.hosts(Arrays.asList(
                            new ServerAddress("cluster0-shard-00-00-ox90k.mongodb.net", 27017),
                            new ServerAddress("cluster0-shard-00-01-ox90k.mongodb.net", 27017),
                            new ServerAddress("cluster0-shard-00-02-ox90k.mongodb.net", 27017)
                    ));
                    builder.requiredReplicaSetName("Cluster0-shard-0");
                })
                .build();

        MongoClient mongoClient = MongoClients.create(settings);

同樣的錯誤： com.mongodb.MongoSocketReadException: Prematurely reached end of stream

更新：嘗試而不是重寫整個文檔，只更改一個字段，如：

Document found = database.getCollection("capped_collection").find(new Document("title", title)
                .append("url", url)
                .append("img", img)
                .append("price", price)).first();

        if (found == null) {
            collection.insertOne(new Document("title", title)
                            .append("url", url)
                            .append("img", img)
                            .append("price", price)
                            .append("sent", false));

    Document doc = collection.find(eq("sent", false)).first();

    if(doc != null){
     collection.updateOne(eq("sent", false), new Document("$set", new Document("sent", true)));
    }

但還是有：

com.mongodb.MongoSocketReadException: Prematurely reached end of stream

---

試過換版本，結果在這里。

有誰知道我需要更正什么或如何解決錯誤Prematurely reached end of stream ？

我感謝任何幫助。

Answer 1

選項1

該錯誤通過連接格式解決（使用參數maxIdleTimeMS 、 ssl和authSource ）：

maxIdleTimeMS - 連接在被移除和關閉之前可以在池中保持空閑的最大毫秒數。

MongoClient mongoClient = MongoClients.create("mongodb://user:mypassword@cluster0-shard-00-00-ox90k.mongodb.net:27017,cluster0-shard-00-01-ox90k.mongodb.net:27017,cluster0-shard-00-02-ox90k.mongodb.net:27017/test?ssl=true&replicaSet=Cluster0-shard-0&authSource=admin&retryWrites=true&maxIdleTimeMS=5000");

---

或者您可以以編程方式配置憑據（使用 java 驅動程序3.6+版本）：

admin - 是在 Atlas 中定義用戶的數據庫；

user - 是用戶名；

mypassword - 是密碼；

MongoCredential credential = MongoCredential.createCredential("user", "admin", "mypassword".toCharArray());
        MongoClientSettings settings = MongoClientSettings.builder()
                .credential(credential)
                .retryWrites(true)
                .applyToConnectionPoolSettings(builder ->
                        builder.maxConnectionIdleTime(5000, TimeUnit.MILLISECONDS))
                .applyToSslSettings(builder -> builder.enabled(true))
                .applyToClusterSettings(builder -> {
                    builder.hosts(Arrays.asList(
                            new ServerAddress("cluster0-shard-00-00-ox90k.mongodb.net", 27017),
                            new ServerAddress("cluster0-shard-00-01-ox90k.mongodb.net", 27017),
                            new ServerAddress("cluster0-shard-00-02-ox90k.mongodb.net", 27017)
                    ));
                    builder.requiredReplicaSetName("Cluster0-shard-0");
                })
                .build();

        MongoClient mongoClient = MongoClients.create(settings);

1. 定義主機名時，提及所有副本集主機名。

這將解決 java.net.UnknownHostException。

2. 您不能像 mongodb+srv 連接那樣使用 DNS 短名稱。

---

選項#2

而且，可以通過調用mongodb.MongoClient.connect一次來解決錯誤，而不是每個請求。 嘗試重構您的代碼以在插入特定文檔期間調用連接一次而不是每次都調用。 在這種情況下，您可以避免選項 #1 中的任何其他參數。

剛剛夠：

mongodb+srv://admin:password@cluster0-ox90k.mongodb.net/test?retryWrites=true&w=majority

---

特別感謝mongoDB 支持。

Answer 2

當您嘗試連接到 Atlas 上的免費集群時，請檢查您的 IP 是否已列入白名單。 Go 1) 添加連接IP地址，點擊IP Access List選項卡，可以添加IP地址。