如何使用mongoDB Java驱动程序3.4或3.6避免异常提前到达流的末尾？（插入时）

Question

我试图插入一些文档，以上限集合使用此代码片段：

            // 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));
        }

这意味着——重写文档。我插入的新文档中有一个字段，而不是旧文档，因为capped collection不允许用另一个大小更新现有文档。因为我遇到了一个例外：无法更改封顶集合中文档的大小。

老医生看起来像：

新版本如下：

这段代码运行良好，但过了一段时间（在插入过程中），我不断收到一个错误：

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)

正如我正确理解的，错误出现在行中（可能只是格式问题）：

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

我研究并试图解决这个错误使用这样的代码（我使用免费的Tier M0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);

同样的错误：com.mongodb.MongoSocketReadExc0019：过早到达流的结尾

更新：尝试不重写完整文档，只更改一个字段，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)));
    }

但仍然有：

com.mongodb.MongoSocketReadException: Prematurely reached end of stream

尝试更改版本，结果如下。

有人知道我需要纠正什么或者如何解决错误吗？

谢谢你的帮助。

Answer 1

通过连接格式（使用参数maxIdleTimeMS、ssl和authSource）解决了错误：

MaxIdleTimes—连接在被删除和关闭之前在池中保持空闲的最大毫秒数。

MongoClient mongoClient = MongoClients.create("mongodb://user:[e-mail]: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");

或者可以通过编程方式配置凭据（使用java驱动程序3.6versions）：

admin——是Atlas中定义用户的数据库；

user-是用户名；

mypassword——是密码；

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);

>

<区块报价>

定义主机名时，提及所有副本集主机名。

这将解决java.net.未知主机异常。

您不能使用DNS短名称作为mongodb srv连接。

而且，这个错误可以通过调用mongoDB来解决。MongoClient.connect一次，而不是每次请求。尝试将代码重组为调用连接一次，而不是在插入特定文档期间每次调用。在这种情况下，您可以避免选项#1中的任何附加参数。

就够了：

mongodb+srv://admin:[e-mail]/test?retryWrites=true&w=majority

特别感谢您对mongoDB的支持。