How to send and receive serialized object in socket channel

Question

I want to transmit a serialized object over a socket channel. I want make "Hi friend" string as serialized object and then write this object in socket channel while in the other end i want to read the same object and retrieve the data.

All these things I want to do using Java SocketChannel. How to do this? I have tried like below, but did not get any data in the recipient side.

private static void writeObject(Object obj, SelectionKey selectionKey) {     ObjectOutputStream oos;     try {         SocketChannel channel = (SocketChannel) selectionKey.channel();         oos = new ObjectOutputStream(Channels.newOutputStream(channel));          oos.writeObject(obj);     } catch (IOException ex) {         ex.printStackTrace();     } }  private static Object readObject(SelectionKey selectionKey) {     ObjectInputStream ois;     Object obj = new Object();     SocketChannel channel = (SocketChannel) selectionKey.channel();     try {         ois = new ObjectInputStream(Channels.newInputStream(channel));         obj = ois.readObject();     } catch (Exception ex) {         ex.printStackTrace();     }     return obj; } 

Answer 1

Your SocketChannel handling seems to be incomplete, see this complete example for SocketChannels transferring a byte:

/*  * Writer  */ import java.io.IOException; import java.io.ObjectOutputStream; import java.net.InetSocketAddress; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SocketChannel;  public class Sender {     public static void main(String[] args) throws IOException {         System.out.println("Sender Start");          ServerSocketChannel ssChannel = ServerSocketChannel.open();         ssChannel.configureBlocking(true);         int port = 12345;         ssChannel.socket().bind(new InetSocketAddress(port));          String obj ="testtext";         while (true) {             SocketChannel sChannel = ssChannel.accept();              ObjectOutputStream  oos = new                        ObjectOutputStream(sChannel.socket().getOutputStream());             oos.writeObject(obj);             oos.close();              System.out.println("Connection ended");         }     } } 

And the Reader

/*  * Reader  */ import java.io.IOException; import java.io.ObjectInputStream; import java.net.InetSocketAddress; import java.nio.channels.SocketChannel;  public class Receiver {     public static void main(String[] args)      throws IOException, ClassNotFoundException {         System.out.println("Receiver Start");          SocketChannel sChannel = SocketChannel.open();         sChannel.configureBlocking(true);         if (sChannel.connect(new InetSocketAddress("localhost", 12345))) {              ObjectInputStream ois =                       new ObjectInputStream(sChannel.socket().getInputStream());              String s = (String)ois.readObject();             System.out.println("String is: '" + s + "'");         }          System.out.println("End Receiver");     } } 

When you first start the Server, then the Receiver, you'll get the following output:

Server's console

Sender Start Connection ended 

Receiver's console

Receiver Start String is: 'testtext' End Receiver 

This is not the best solution, but follows your use of Java's ServerSocketChannel