Java in a Nutshell, 5th Edition

Name

ServerSocket

Synopsis

This class is used by servers to listen for connection requests from clients. Before you can use a ServerSocket, it must be bound to the local network address that it is to listen on. All of the ServerSocket( ) constructors except for the no-argument constructor create a server socket and bind it to the specified local port, optionally specifying a “connection backlog” value: this is the number of client connection attempts that may be queued up before subsequent connection attempts are rejected.

In Java 1.4 and later, the no-argument ServerSocket( ) constructor allows you to create an unbound socket. Doing this allows you to bind the socket using the bind( ) method which uses a SocketAddress object rather than a port number. It also allows you to call setReuseAddress( ) , which is only useful when done before the socket is bound. Call isBound( ) to determine whether a server socket has been bound. If it has, use getLocalSocketAddress( ) or getLocalPort( ) and getInetAddress( ) to obtain the local address it is bound to.

Once a ServerSocket has been bound, you can call the accept( ) method to listen on the specified port and block until the client requests a connection on the port. When this happens, accept( ) accepts the connection, creating and returning a Socket the server can use to communicate with the client. A typical server starts a new thread to handle the communication with the client and calls accept( ) again to listen for another connection. ...