Java中的Socket服务中如何实现客户端和服务端多次通讯

比如，服务器给客户端发一个信息。然后服务端根据客户端发送的信息判断，再回复一个信息，就是多次读和写的问题

可以利用多线程， 服务器端不断接收客户端连接， 连接一个就开一个线程处理 客户端的交互，

这里有一个简单的例子，Client端发送消息给Server端，并读取Server端的回复信息；而Server端则先读取Client端的数据，再回复数据。
Server端：

 public class Main {
    public static void main(String[] args) {
        ServerSocket server;
        try {
            server = new ServerSocket(8800);
            System.out.println("Wait for connection...");
            Socket socket = server.accept();
            BufferedInputStream is = new BufferedInputStream(
                    socket.getInputStream());
            byte[] buff = new byte[1024];
            int size;
            while ((size = is.read(buff)) != -1) {
                System.out.println(new String(buff, 0, size));
            }

            OutputStream os = socket.getOutputStream();
            os.write("您好，我是Server端".getBytes());
            os.flush();
            os.close();
            System.out.println("ok,client send over.");
            server.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Client端：

 public class Client {
    public static void main(String[] args) throws Exception 
    {
        Socket s = new Socket("localhost",8800);
        OutputStream os = s.getOutputStream();
        os.write("您好，我是客户端".getBytes());
        os.close();

        InputStream in = s.getInputStream();
        byte[] buff = new byte[1024];
        BufferedInputStream is = new BufferedInputStream(in);
        int size;
        while((size = is.read(buff)) != -1){
            System.out.println(new String(buff,0,size));
        }
        System.out.println("over...");
        s.close();
    }
}