socket使用中ObjectOutputStream ,ObjectInputStream的问题

服务器端
try {
ServerSocket server = new ServerSocket(5678);
Socket client=server.accept();
ObjectInputStream in=new ObjectInputStream(client.getInputStream());
PrintWriter out=new PrintWriter(client.getOutputStream()); 
   try {
list=(List) in.readObject();
   } catch (ClassNotFoundException e) {}
out.flush(); 
client.close();
} catch (IOException e) {}客户端 
try {
server=new Socket(InetAddress.getLocalHost(),5678);
in=new BufferedReader(new InputStreamReader(server.getInputStream())); 
out=new ObjectOutputStream(server.getOutputStream()); 
out.writeObject(list);
out.flush();
String test=in.readLine();
server.close();
} catch (IOException e1) {} 客户端用ObjectOutputStream流将list传给服务器端
可我这么写服务器端接收不到list,不知道错在哪,还是使用方法错了,请前辈们指教