大家帮我看下这个程序有没有问题，为什么我测试时什么从客户端的控制台输入，服务端的控制台没有输出呢
客户端
import *;
import *;

public class ClientSide {

    private Socket socket;
    private BufferedReader reader;
    private PrintWriter writer;
   
    public ClientSide()
    {
        try{
            socket=new Socket(InetAddress.getByName("localhost"),4700);
            reader=new BufferedReader(new InputStreamReader(socket.getInputStream()));
            writer=new PrintWriter(new OutputStreamWriter(socket.getOutputStream()),true);
        }
        catch(IOException e){
            System.out.println("Build Socket Error:"+e);
            System.exit(1);
        }
    }
    public void ClientStart()
    {
        try{
            BufferedReader readConsole=new BufferedReader(new InputStreamReader(System.in));
            String str;
            while((str=readConsole.readLine())!=null){
                writer.write(str);
                str=reader.readLine();
                System.out.println(str);
            }
            reader.close();
            writer.close();
            socket.close();
        }
        catch(IOException e){
            System.out.println("Error while client start:"+e);
        }
    }

    /**
     * @param args
     */
    public static void main(String[] args)throws IOException {
        // TODO Auto-generated method stub
        ClientSide client=new ClientSide();
        client.ClientStart();
    }

}
服务端
import *;
import *;

public class ServerSide {

    private ServerSocket serversocket;
    private Socket socket;

    public ServerSide(){
        try{
            serversocket=new ServerSocket(4700);
        }
        catch(IOException e){
             System.out.println("Build ServerSocket Error:"+e);
             System.exit(1);
        }
    }
    public void ServerStart() throws IOException{
        try{
            while(true){
                socket=serversocket.accept();
                new ServerThread(socket);
            }
        }
        catch(IOException e){
            System.out.println("ServerSocket can't accept a socket:"+e);
        }
        finally{
            socket.close();
            serversocket.close();
        }
    }
    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        try{
            ServerSide server=new ServerSide();
            server.ServerStart();
        }
        catch(IOException e){
            System.out.println("Can't no close ServerSocket");
        }
    }

}


class ServerThread extends Thread{
    private BufferedReader reader;
    private PrintWriter writer;
   
    public ServerThread(Socket soc){
        try{
            reader=new BufferedReader(new InputStreamReader(soc.getInputStream()));
            writer=new PrintWriter(new OutputStreamWriter(soc.getOutputStream()),true);
            start();
        }
        catch(IOException e){
            System.out.println("Bulid ServerThread Error:"+e);
            System.exit(1);
        }
    }
    public void run() {
        try{
            String str;
            while((str=reader.readLine())!="BYT"){
                writer.write(str);
                System.out.println(str);
            }
            reader.close();
            writer.close();
        }
        catch(IOException e){
            System.out.println("Read ClientSide Input Error:"+e);
        }
    }
}

悲剧啊，忘了启动线程了。