java关于socket服务器与客户端交互

我的程序执行结果出现java.net.SocketException: Connection reset，初学者，求大神解决
服务器发送usr给客户端
客户端收到usr后发送linda给服务器，
服务器收到linda就回复welcome，否则回复wrong name
代码如下：

服务器：

  import java.net.*;
import java.io.*;
public class ServerRegister {
    public static void main(String args[])
    {
        try{
        ServerSocket Ss=new ServerSocket(1111);
        Socket s=Ss.accept();
        PrintStream out=new PrintStream(s.getOutputStream());
        BufferedReader in=new BufferedReader(new InputStreamReader(s.getInputStream()));

            while(true)
            {
                System.out.println("send to Client "+"user:");
                out.println("user");
                String x=in.readLine();
                System.out.println("get from client"+x);
                if(x.equals("linda"))
                {
                    System.out.println("send to Client"+"Login welcome!");
                    out.println("welcome!");
                }
                else
                    out.println("wrong name");
                out.close();
                in.close();
                s.close();
            }
        }catch(IOException e)
        {
            System.out.println(e.toString());
        }
    }

}

客户端：

 import java.io.*;
import java.net.*;
public class ClientRegister {
    public static void main(String args[])
    {
        try
        {
            Socket s=new Socket("127.0.0.1",1111);
            BufferedReader in=new BufferedReader(new InputStreamReader(s.getInputStream()));
            PrintStream out=new PrintStream(s.getOutputStream());
            String x=in.readLine();
            if(x.equals("user:"))
            {
                System.out.println("get from server:"+x);
                System.out.println("send to server"+"linda");
                out.println("linda");
                x=in.readLine();
                System.out.println("get from server"+x);
                if(x=="welcome!")
                {
                    System.out.println("register sussfully");

                }
                else if(x=="wrong name")
                    System.out.println("register unsussfully");
            }else{
                System.exit(0);}
            out.close();
            in.close();
            s.close();
        }catch(IOException e)
        {
            System.out.println(e.toString());
        }
}

    }

你是想发送什么 看不懂

BufferedReader in=new BufferedReader(new InputStreamReader(s.getInputStream())); 客户端的 (s.getInputStream()）

服务器发送usr：给客户端
客户端收到usr后发送linda给服务器，
服务器收到linda就回复welcome否则回复wrong name