我对Java和MongoDB(或任何数据库)非常陌生,我一直在构建这个Java程序来测试连接。它只是简单地建立连接并列出所有现有的数据库名称。
import com.mongodb.MongoClient;
import com.mongodb.client.MongoCursor;
public class test {
public static void main(String[] args) {
try{
MongoClient mongoClient = new MongoClient( "localhost" , 27017 );
MongoCursor<String> dbsCursor = mongoClient.listDatabaseNames().iterator();
while(dbsCursor.hasNext()) {
System.out.println(dbsCursor.next());
}
}catch(Exception e){
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
}
}
}
MongoDB服务器已经启动。但是,当我运行此应用程序时,它显示以下错误。
Jun 25, 2016 3:35:06 PM com.mongodb.diagnostics.logging.JULLogger log
INFO: Cluster created with settings {hosts=[localhost:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
Jun 25, 2016 3:35:06 PM com.mongodb.diagnostics.logging.JULLogger log
INFO: No server chosen by ReadPreferenceServerSelector{readPreference=primary} from cluster description ClusterDescription{type=UNKNOWN, connectionMode=SINGLE, all=[ServerDescription{address=localhost:27017, type=UNKNOWN, state=CONNECTING}]}. Waiting for 30000 ms before timing out
Jun 25, 2016 3:35:06 PM com.mongodb.diagnostics.logging.JULLogger log
INFO: Exception in monitor thread while connecting to server localhost:27017
com.mongodb.MongoSocketWriteException: Exception sending message
at com.mongodb.connection.InternalStreamConnection.translateWriteException(InternalStreamConnection.java:462)
at com.mongodb.connection.InternalStreamConnection.sendMessage(InternalStreamConnection.java:205)
at com.mongodb.connection.CommandHelper.sendMessage(CommandHelper.java:89)
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.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:128)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.SocketException: Software caused connection abort: socket write error
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:109)
at java.net.SocketOutputStream.write(SocketOutputStream.java:153)
at com.mongodb.connection.SocketStream.write(SocketStream.java:75)
at com.mongodb.connection.InternalStreamConnection.sendMessage(InternalStreamConnection.java:201)
... 7 more
com.mongodb.MongoTimeoutException: Timed out after 30000 ms while waiting for a server that matches ReadPreferenceServerSelector{readPreference=primary}. Client view of cluster state is {type=UNKNOWN, servers=[{address=localhost:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketWriteException: Exception sending message}, caused by {java.net.SocketException: Software caused connection abort: socket write error}}]
Process finished with exit code 0
这些意味着什么?我应该设置ReadPreferenceServerSelector吗?但是我在网上找不到任何相关的文档。