ObjectInputStream - ObjectOutputStream, socket problem

Hello,
I'm tring to send and receive some object between a client and a server application.
When the client application send an object the server is stock.
This is a part of the server code:
try
inObj = new ObjectInputStream(client.getInputStream()); /// here the server program is stock
     mes1 = (Message) inObj.readObject();
     System.out.println(mes1);
     out.println("end");
catch (ClassNotFoundException e)
e.printStackTrace();
catch(IOException e)
     e.printStackTrace();
The client code:
try
     in=new BufferedReader(new InputStreamReader(soclu.getInputStream()));
     out=new PrintWriter(new BufferedWriter(new OutputStreamWriter(soclu.getOutputStream())),true);
     outObj = new ObjectOutputStream(soclu.getOutputStream());
     out.print("Info");
     //          out.flush();
     outObj.writeObject(m1);
     outObj.flush();
     raspuns = in.readLine();
     System.out.println(raspuns);
     System.out.println("Closing the communication!");
     out.print("end");
     out.close();
     in.close();
     outObj.close();
     soclu.close();
catch(IOException e)
     System.out.println("Problems Tx/Rx");
     e.printStackTrace();
The class Message implements Serializable
if there is somebody hwo cold help me I appreciate that.
Thnak you,
aclaudia1

You should not be opening both a PrintWriter and an ObjectOutputStream on the same socket. You should use a single stream to do all the output on the socket.

Similar Messages

ObjectOutputStream/ObjectInputStream/Socket Problem

I make request on a server with socket connection.
I want to use one socket open connection.
So, I don't close the socket.
This is like that :
public void serverConnection()
try
DataOutputStream out = new DataOutputStream(s.getOutputStream());
ObjectOutputStream objectOutStream = new ObjectOutputStream(out);
objectOutStream.writeObject(configConnection);
DataInputStream in = new DataInputStream(s.getInputStream());
ObjectInputStream objectInStream = new ObjectInputStream(in);
arrayBlocks = (BFTransactionBlock[]) objectInStream.readObject();
} catch (Exception e)
valid = false;
System.out.println("Error " + e);
When I use this funtion more then one time with the same socket, the prorgam wait an the instruction :
ObjectInputStream objectInStream = new ObjectInputStream(in);
I use objectInStream.close() ...
But it create an other problem : i lost the socket connection.
What's the solution ?

You don't need a new input stream for the same socket. You just need to read the data off of the original socket.
DataInputStream in = new DataInputStream(s.getInputStream());
ObjectInputStream objectInStream = new ObjectInputStream(in);The above code is fine. You need to loop through the code below until you are done with the socket. Then you close the socket. If you close the stream, you will close the underlying socket.
arrayBlocks = (BFTransactionBlock[]) objectInStream.readObject();

Sockets problem

Hi ,
I written a server class that simply writes the numbers and the client simply reads those numbers and prints them. When I run the both client and server on tha same machine there is no data loss found. But when I run the server on different machine than client I found heavy dataloss.(while theserver written numbers from 1-9000 the client is able read only 6000 plus). The data loss is increased when the data read from the server socket created by the VB application. Here with i am pasting the code snippet for the Server and the Client java files . Please help me in solving this problem.
Client.java
import java.net.*;
import java.io.*;
public class Client
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Server.java
import java.net.*;
import java.io.*;
public class Server
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thanks in advance,
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This has nothing to do with JSSE; please post in a more appropriate forum.

Data socket problems with LVRT 8.2

I am in the process of migrating to LV 8.2 from LV7.1.1. My system has 18 RT targets which send data to a Host PC through data socket (DS). The Host PC runs LV on Windows XP Pro. With LV7.1.1 on both host and RT targets DS works perfectly. The RT targets update the host every 500 ms.
I've taken a three-step process in the migration. First tests were done with the host migrated to LV8.2 while keeping the RTs at LV7.1.1. Result: the system worked perfect. Then I changed one RT to 8.2 keeping the rest the rest at LV7.1.1. Result: DS timed out before all the data could be sent to Host. Finally, all RTs were migrated to LVRT 8.2. Result: Only about 5 out of the 18 RTs report to the Host before DS times out. However, if only one RT target is used, i.e., the other 17 RTs are diasbled, communication is very fast. Is there a special setting that I need to make? Btw, the roughly 5 RTs that report vary randomly from test to test, i.e., there is no bias towards any particular RTs.
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Vancouver, Canada

Ben,
I must say I am very surprised by Nadim's email. His point, which I must say I don't agree with, was made quite clear to me yesterday during a conference call between my team and the NI team comprising Chris, Nadim, and Avinash. So I don't know what purpose this morning's email is supposed to serve. Be that as it may, I think NI has gotten it wrong here. I do not think it should be one or the other. The discussion forum is a much wider forum comprised of people with varying experiences - not just NI employees. That is precisely why I posted my problem to the forum: to tap into the vast experiences of the discussants. But when I did not get any responses after I had posted answers to Nadim's questions, I decided to make a formal service request to NI, all perfectly legal. So I was really surprised when I was being blamed for tying up NI resources on one problem. I believe the resource allocation issue should be NI's to solve, not mine. I have no way of knowing that NI had formally assigned somebody to my problem. What if nobody from NI responds, am I allowed to make a service request to NI? My feeling is that NI's logic is flawed here, assuming Nadim's views are NI's views.
Thanks,
Chatonda Mtika
Algis Corporation
Vancouver, Canada

Serversock/socket problem pls Help

Hi all,
I have a serversocket that accepts client's connections, reads from this stream, processes the data and sends back response to the client. This works fine for a standard scenario.
The problem occurs if for some reason the client looses connection after writing to the serversocket. The server behaves as if nothing happens and sends back the response. I want the server to be able to detection any connection loss and report back. My code snippet is shown below
ServerSocket server;
Socket conn;
BufferedReader input;
PrintWriter out;
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server= new ServerSocket(4550,10);
conn=server.accept();
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process data .....
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}catch(IOException e){
e.printStackTrace();
}finally{
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Regards
Tim

err, yeah, i got that bit....
and there is nothing, nothing at all in java, C, C++, any and i mean ANY TCP/IP programming that can tell if the client has been unplugged without trying to send something to it
you can use a keepAlive in Socket to automatically occasionally send a dummy packet (for which it expects a response)
but apart from that the Socket cannot know it is not connected unless it recieves indication from the client (the end that is closed first sends a FIN packet and the other end replies with ACK FIN)
a pair of Sockets connectd through a network does not get a permanent physical connection, they give the impression of such by exchanging packets with sequence numbers and ack numbers coresponding to the last packet recived.
if neither Socket has nothing to send, nothing is sent and it is assumed that the connection is still valid, so isConnected() will return true unless it actually knows that the client has closed the connection or an Exception occured when it tried to send something
isConnected() does not test the connection, just reports true if it has been connected and there has not been an IOException or either end has closed
maybe you could explain why you need to avoid sending the response if the client has been unplugged?

Create OPC I/O server and front panel data socket problem

Hi all!
I installed the NI OPC server. When I try to create a new server I/O in a LabVIEW project I don't see the "OPC client" possibility.
Is something software missing?
Other question: I tryed to connect to OPC server using front panel data socket but my problem is same. When I click the numeric control and I go to the "data operation" menu there is no possibility to make data socket connection.
I don't know what is the problem.
I attached two pictures about my problem.
Solved!
Go to Solution.

Dear vajasgeri1,
do you have LabVIEW DSC module installed? Without it you will not have the OPC client funtionality.
And to configure DataSocket binding you need to go to the Data Binding tab in the Properties of a control.
BR,
Mateusz Stokłosa
Applications Engineer
National Instruments

Socket Problem, Problem about printing the response from server

Or even I am not sure if there is a response from server. My code is like that
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problem is solved, the reason it doesn't work is i didn't write the parts correctly. I mean it should be exactly the same packetIf you mean that the entire request must be sent in a single IP packet, this isn't true.
and host name must also be exactly sent to server.Of course.
They must be like in the wireshark.No. The actual data you send must be the same, but the server has no way of telling about what the IP packet looks like or how many there were.
One of your problems is that newlines in HTTP are defined as \r\n. In one case you're just using \n and in the other case you're using whatever the platform line terminator is. Neither is correct.

Datagram Socket Problem !!!!!!!!!!!!!!!

Hi to All ,
I am facing problem regarding the Datagram Socket Programming .
I wana to make a java program that is using the datagram socket. I wana to retrive the IP Address of all the machines that are connected in a local network by using the datagram Socket !!!!!!!!!!!!!!
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You can't use any Java to find all the machines on your network (whatever that means). You will need to shell out and parse the output from the shell.
If you want to simply use datagram sockets to send UDP broadcasts, the Javadoc covers it in some detail.
However, UDP is called a "send and pray" protocol - you send the message and pray that the client receives it. Also, there is no acknowledgement from the client when the message is received. So, in a nutshell, you cannot use multicasts to find clients.
You need to use some other protocols in the TCP/IP stack for finding machines on the network - and Java does not have any pre-built support for these.

File transfer via socket problem (with source code)

I have a problem with this simple client/server filetransfer program. When I run it, only half the file is transfered via the net? Can someone point out to me why this is happening?
Client:
import java.net.*;
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Server:
import java.net.*;
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Hi!!
The problem is at this line:
System.out.println("Copies "+fileIn.read(buffer)+" bytes");
Just comment out this line of code and see the difference. This line of code causes another "read" statement to be executed, but you are writing only the data read from the first read statement which causes approximately half the file to be send to the server.

Reading data from socket problem

Hello;
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Sometimes I cannot get the data in one chunk but I have solved that problem(I hope).. Here is my code:
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And don't use ready() or available as a test for end of stream like that. That's not what it's for. (What is is for is a moot question.) Using it like that is a recipe for losing data.

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Started; log sequence number 0 43655
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Here was my solution/workaround for this issue to the rest of us poor fellas that have too fight around with Squeezebox server from time to time:
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http://wiki.slimdevices.com/index.php/ExistingMySQLInstance
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Enter password: admin_password
Welcome to the MySQL monitor.
Commands end with ; or \g.
Your MySQL connection id is 103 to server version: 5.0.24a-log
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Query OK, 0 rows affected (0.13 sec)
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Query OK,
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dbpassword: slimserver_password
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//// Start Code ////
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Hi,
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It says at the top :) think i posted too much code but that way everyone knows exactly what is happening. Cant get the StartConv class to commmunicate with the ChatHandler basically

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Hey all, basically the problem i got is related to sockets, client program freezes up once i press the button 'send', Mainly all im trying to do right now is have a client send text to the server, then the server sends back whatever the client sent and this is then shown on the clients screen..
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}However after debugging the application, i think the main problem comes from the server side, mainly the while loop which keeps looping to see if the input recieved is null, i think the problem why the client freezes up is because nothing is being sent therefore the loops keeps going on in circles, hence not supplying the client with any text..
I would appreciate if someone could give me some help how to fix this problem
Thanks

What else could the server do? There's no problem there. The problem is that you're calling network code inside an actionPerformed method. This freezes your GUI because the method is invoked within the AWT thread, which handles all the events on the GUI. As your code is blocked in network operations, no GUI events can be processed.
Do the network operations in a separate thread.

ObjectInputStream - ObjectOutputStream, socket problem

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