问题
I am making a prototype client & server so that I can understand how to handle reconnects.
The server ought to create a serversocket and listen forever. A client may connect, send its data, and close its socket but it will not send a "I'm done and closing" type message to the server. For this reason, the server gets a EOFException
when it does a readByte()
since the remote client has closed. In the error handler for the EOFException
, it will close the socket and open a new one.
Here's the problem: The client sometimes gets a SocketWriteError
when it does the outputStream.write()
call even after it successfully opens the socket/inputstream/outpustream. It may have something to do with the frequency that I'm opening and closing these sockets. One interesting thing is that the client does an arbitrary number of writes/close/reconnects before crapping out. It will sometimes crap out on the first reconnect, other times it will take 50 reconnects before seeing the SocketWriteError
.
Here's the error on the client side:
java.net.SocketException: Connection reset by peer: socket write error at java.net.SocketOutputStream.socketWrite0(Native Method) at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92) at java.net.SocketOutputStream.write(SocketOutputStream.java:115) at bytebuffertest.Client.main(Client.java:37)
Here are some snippets of code:
SERVER:
public static void main(String[] args)
{
Server x = new Server();
x.initialize();
}
private void initialize()
{
ServerSocket s;
InputStream is;
DataInputStream dis;
while (true) //ADDED THIS!!!!!!!!!!!!!!!!!!!!!!
{
try
{
s = new ServerSocket(4448);
s.setSoTimeout(0);
s.setReuseAddress(true);
is = s.accept().getInputStream();
System.out.println("accepted client");
dis = new DataInputStream(is);
try
{
byte input = dis.readByte();
System.out.println("read: " + input);
} catch (Exception ex)
{
System.out.println("Exception");
dis.close();
is.close();
s.close();
}
} catch (IOException ex)
{
System.out.println("ioexception");
}
}
}
CLIENT:
public static void main(String[] args)
{
Socket s;
OutputStream os;
try
{
s = new Socket("localhost", 4448);
s.setKeepAlive(true);
s.setReuseAddress(true);
os = s.getOutputStream();
int counter = 0;
while (true)
{
try
{
os.write((byte) counter++);
os.flush();
os.close();
s.close();
s = new Socket("localhost", 4448);
s.setKeepAlive(true);
s.setReuseAddress(true);
os = s.getOutputStream();
} catch (Exception e)
{
e.printStackTrace();
System.err.println("ERROR: reconnecting...");
}
}
} catch (Exception ex)
{
ex.printStackTrace();
System.err.println("ERROR: could not connect");
}
}
Does anyone know how to properly reconnect?
回答1:
Don't close the ServerSocket on an error, just .accept() a new connection.
What I normally do is each time ServerSocket.accept() returns a Socket, I spawn off a thread to handle sending and receiving from that Socket. That way you're ready to start accepting a new connection as soon as somebody wants to connect to you.
来源:https://stackoverflow.com/questions/674892/java-reconnection-on-a-socket-sometimes-gives-error