高手在吗？求助下这个非常简单的程序

Question

import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Sim{
JTextArea incoming;
JTextField outgoing;
BufferedReader reader;
PrintWriter writer;
Socket sock;

public static void main(String[] args){
new Sim().go();
}
public void go(){
JFrame frame = new JFrame("Simple Chat Client");
JPanel panel = new JPanel();
incoming = new JTextArea(15,50);
incoming.setLineWrap(true);
incoming.setWrapStyleWord(true);
incoming.setEditable(false);
JScrollPane qScroller = new JScrollPane(incoming);
qScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
qScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
outgoing = new JTextField(20);
JButton sendButton = new JButton("send");
sendButton.addActionListener(new sendButtonListener());
panel.add(qScroller);
panel.add(outgoing);
panel.add(sendButton);
setUpNetworking();

Thread readerThread = new Thread(new IncomingReader());
readerThread.start();

frame.getContentPane().add(BorderLayout.CENTER,panel);
frame.setSize(400,500);
frame.setVisible(true);
}

private void setUpNetworking(){
try{
sock = new Socket("127.0.0.1",5000);
InputStreamReader streamReader = new InputStreamReader(sock.getInputStream());
reader = new BufferedReader(streamReader);
writer = new PrintWriter("networking established");

}catch(IOException ex){
ex.printStackTrace();
}
}public class sendButtonListener implements ActionListener{
public void actionPerformed (ActionEvent ev){
try{
writer.println(outgoing.getText());
writer.flush();
}catch(Exception ex){
ex.printStackTrace();
}
outgoing.setText("");
outgoing.requestFocus();
}
}
public class IncomingReader implements Runnable{
public void run(){
String message;
try{

while((message = reader.readLine())!= null){
System.out.println("read"+message);
incoming.append(message+"\n");
}
}catch(Exception ex){ex.printStackTrace();}
}
}
}
这个是客户端程序
import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;public class SimSever{
//ArrayList<Object>clientOutputStreams = new ArrayList<Object>();
ArrayList clientOutputStreams;
public class ClientHandler implements Runnable{
BufferedReader reader;
Socket sock;
public   ClientHandler(Socket clientSocket){
try{
sock = clientSocket;
InputStreamReader isReader = new InputStreamReader(sock.getInputStream());
reader = new BufferedReader(isReader);

}catch(Exception ex){ex.printStackTrace();}
}
public void run(){
String message;
try{
while ((message = reader.readLine())!= null){
System.out.println("read"+message);
tellEveryone(message);
}
}catch(Exception ex){ex.printStackTrace();}
}
}
public static void main(String[] args){
new SimSever().go();
}
public void go(){
clientOutputStreams = new ArrayList();
try{
ServerSocket severSock = new ServerSocket(5000);while(true){
Socket clientSocket = severSock.accept();
PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
clientOutputStreams.add(writer); Thread t = new Thread(new ClientHandler(clientSocket));
t.start();
System.out.println("got a connection");}}catch(Exception ex){
ex.printStackTrace();
}}
public void tellEveryone(String message){
Iterator it = clientOutputStreams.iterator();
while (it.hasNext()){
try{
PrintWriter writer = (PrintWriter) it.next();
writer.println(message);
writer.flush();

}catch(Exception ex){ ex.printStackTrace(); }
}
}
}
这个是服务器端
请问用dos打开服务器端 然后打开客户端的啥时候  服务器显示 得到链接 
但是在客户端发信息 在那个面板不显示 是哪里的问题啊？
本校菜鸡刚学java1个月 真心求教各位大侠

Answer 1

1 客户端一旦运行 
 sock = new Socket("127.0.0.1",5000);
服务器端就显示连接。2 PrintWriter初始化有点问题。            //writer = new PrintWriter("networking established");
    writer = new PrintWriter(sock.getOutputStream());