java网络编程入门程序问题？

import java.io.*;import java.net.*;public class ChatServer {        public static void main(String []args) {                try {                        ServerSocket ss = new ServerSocket(6888);                        Socket so = ss.accept();                        BufferedReader br = new BufferedReader(new InputStreamReader(so.getInputStream()));                        BufferedReader brs = new BufferedReader(new InputStreamReader(System.in));                        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(so.getOutputStream()));                        String s = br.readLine();                        System.out.println("Client" + s);                      String c = null;                        while(s != "exit") {                                System.out.println("Client : " + s);                                    c = brs.readLine();                                bw.write(c);                                bw.flush();                                System.out.println("Server : " + c);                                s = br.readLine();                            }                          System.out.println("Chat Over");                        br.close();                        brs.close();                        bw.close();                }                catch(Exception e) {}           }   }

我的一个小程序，上面是server

import java.io.*;import java.net.*;public class ChatClient {        public static void main(String []args) {                try {                        Socket so = new Socket("127.0.0.1",6888);                        BufferedReader br = new BufferedReader(new InputStreamReader(so.getInputStream()));                        BufferedReader brw = new BufferedReader(new InputStreamReader(System.in));                        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(so.getOutputStream()));                        String c = brw.readLine();                        bw.write(c);                        System.out.println("client" + c);                        while(c != "exit") {                                bw.write(c);                                bw.flush();                                System.out.println("Client : " + c);                                System.out.println("Server : " + br.readLine());                                    c = brw.readLine();                        }                           System.out.println("Chat Over");                        br.close();                        brw.close();                        bw.close();                }                catch(Exception e) {}           }   }

这是client，其实就是一个简单的，白痴的对话器，但是我怎么调试也不对，编译通过了，但是运行的时候一直卡在那里，感觉是io出问题了，大师们劳烦看看呗。非常感谢，实在是自己看不出来了。。。。。