How can I send multiple objects over one socket in java?

Question

When I send only one object through a socket i am ok. But when i am trying to send two objects, i get

Exception in thread "main" java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source))

I have tried almost everything like flush() or reset() but none of them work.

public String SendObject(Object o) throws IOException {
    OutputStream outToServer = client.getOutputStream();
    ObjectOutputStream out = new ObjectOutputStream(outToServer);
    out.writeUnshared(o);
    InputStream inFromServer = client.getInputStream();
    DataInputStream in = new DataInputStream(inFromServer);
    return in.readUTF();
}

Please edit your original post with the code you have (properly formatted). Don't put it in comments. Also, include the exact errors that you got. — sstan
– sstan, Commented Jun 7, 2015 at 1:04

Elliott Frisch · Accepted Answer · 2015-06-07 01:17:48Z

1

You're using an ObjectOutputStream to write the Object(s) from the client. You should be using an ObjectInputStream (not a DataInputStream) to read them on the server. To read two Objects might look something like,

InputStream inFromServer = client.getInputStream();
ObjectInputStream in = new ObjectInputStream(inFromServer);
Object obj1 = in.readObject();
Object obj2 = in.readObject();

Also, on the client, I think you wanted writeObject (instead of writeUnshared) like

ObjectOutputStream out = new ObjectOutputStream(outToServer);
out.writeObject(o);

edited Jun 7, 2015 at 1:17

answered Jun 7, 2015 at 1:07

Elliott Frisch

202k20 gold badges166 silver badges265 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

orestiskim Over a year ago

but why does it work when i send just one object?I have tried the WriteObject and i had the same results

Elliott Frisch Over a year ago

@orestiskim Did you check the writeUnshared Javadoc?

user207421 Over a year ago

Nothing wrong with using writeUnshared() here: indeed, good idea if he is planning to re-send objects.

user207421 · Accepted Answer · 2015-06-07 01:23:13Z

1

You must use the same streams for the life of the socket, not new ones per send (or receive).
You need to decide between Object streams and Data streams. Don't mix them.
Don't try to mix between writeObject()/writeUnshared() and readUTF().

answered Jun 7, 2015 at 1:23

user207421

312k45 gold badges324 silver badges493 bronze badges

Comments

Stephen C · Accepted Answer · 2015-06-07 01:32:02Z

1

While the other answers (e.g. @EJP's) are correct about the right way to send / receive objects and handle the streams, I think that the immediate problem is on the server side:

Exception in thread "main" java.net.SocketException: Connection reset

This seems to be saying that the connection has broken before the client receives a response. When the client side attempts to read, it sees the broken (reset) connection and throws the exception.

If (as you say) the sendObject method works first time, then I suspect that the server side is closing its output stream to "flush" the response ... or something like that.

answered Jun 7, 2015 at 1:32

Stephen C

723k95 gold badges849 silver badges1.3k bronze badges

2 Comments

orestiskim Over a year ago

so what do u suggest?

Stephen C Over a year ago

I suggest that you look at what the server side is doing.

Collectives™ on Stack Overflow

How can I send multiple objects over one socket in java?

3 Answers 3

3 Comments

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

3 Comments

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related