Creating a socket server which allows multiple connections via threads and Java

by

The problem is that currently you’re accepting the connection, but then immediately performing blocking reads on it until it’s closed:

// After a few changes...
Socket clientSocket = serverSocket.accept();
BufferedReader in = new BufferedReader(new InputStreamReader(
     clientSocket.getInputStream()));
String nextLine;
while ((nextLine = in.readLine()) != null) {
    System.out.println(nextline);
}

That means the same thread which accepts the connection is trying to handle the connection. That won’t let you use multiple connections at the same time.

Instead, create a class (e.g. ConnectionHandler) which implements Runnable, and has a constructor taking a Socket. Its run method should handle the connection. Then change your code to:

Socket clientSocket = serverSocket.accept();
Runnable connectionHandler = new ConnectionHandler(clientSocket);
new Thread(connectionHandler).start();

That will leave your “main” thread free to wait for the next connection.

(By the way, the KnockKnockProtocol class isn’t really “external” – it’s part of the example. They just didn’t make it very clear that the source is here…)

More Related Contents:

  1. Official reasons for “Software caused connection abort: socket write error”
  2. Java socket API: How to tell if a connection has been closed?
  3. Getting the IP address of the current machine using Java
  4. What’s causing my java.net.SocketException: Connection reset? [duplicate]
  5. Java sending and receiving file (byte[]) over sockets
  6. Sockets: Discover port availability using Java
  7. socket programming multiple client to one server
  8. Why is it impossible, without attempting I/O, to detect that TCP socket was gracefully closed by peer?
  9. Get MAC address on local machine with Java
  10. Java socket/serialization, object won’t update
  11. Setting a timeout for socket operations
  12. Asynchronous IO in Java?
  13. How to identify end of InputStream in java
  14. What is the difference between connection and read timeout for sockets?
  15. How can I determine the IP of my router/gateway in Java?
  16. java.io.StreamCorruptedException: invalid type code: 00
  17. Java Creating a new ObjectInputStream Blocks
  18. Send HTTP request manually via socket
  19. Sending a message to all clients (Client – Server communication)
  20. Simple Java Client/Server Program
  21. Close multiple resources with AutoCloseable (try-with-resources)
  22. Bluetooth Connection failed “java.io.IOException: read failed, socket might closed or timeout, read ret: -1”
  23. java.net.SocketException: Invalid argument: connect
  24. Cannot assign requested address using ServerSocket.socketBind
  25. Sending and receiving files on socket
  26. java.net.SocketTimeoutException: Read timed out under Tomcat
  27. java socket / output stream writes : do they block?
  28. Using Sockets to send and receive data
  29. ObjectInputStream(socket.getInputStream()); does not work
  30. JDBC MySQL connection using Unix Socket

Leave a Comment