我对编程很陌生，尤其是套接字编程。我试图弄清楚通信实际上是如何工作的(不是在我所有的书中)，但立即遇到了我下载的 SimpleEchoServer 示例的第一个问题。 Communicationflow 工作但是当 Clientsocket 关闭他的连接而不发送特定的字符串时，我的 serversocket 崩溃了。你能告诉我我做错了什么吗？

这是服务器端:

import java.net.*; 
import java.io.*; 
import java.net.InetAddress;

public class EchoServer { 

public static void main(String[] args) throws IOException { 

    ServerSocket serverSocket = null;
    Integer port = new Integer(args[0]);

    try { 

        serverSocket = new ServerSocket(port); 

        } 

    catch (IOException e) { 

            System.err.println("Could not listen on port: "+port); 
            System.exit(1); 

        } 

    Socket clientSocket = null; 
    System.out.println ("Waiting for connection on port "+port+" ...");

    try { 

        clientSocket = serverSocket.accept(); 

        }

    catch (IOException e) { 

            System.err.println("Accept failed."); 
            System.exit(1);

        } 

    System.out.println ("Connection successful");
    System.out.println ("Waiting for input.....");

    PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true); 
    BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream(), "UTF-8")); 

    String inputLine; 

    while ((inputLine = in.readLine()) != null) { 

        System.out.println ("received: " + inputLine); 
        out.println(inputLine); 

        if (inputLine.equals("Bye.")) 
        break; 

    } 

    out.close(); 
    in.close(); 
    clientSocket.close(); 
    serverSocket.close(); 

   } 

}

那是客户端

import java.io.*;
import java.net.*;

public class EchoClient {

    public static void main(String[] args) throws IOException {

    String serverHostname = new String (args[0]);
    Integer port = new Integer(args[1]);

    if (args.length > 0)

        serverHostname = args[0];
        System.out.println ("Attemping to connect to host " + serverHostname + " on port 10007.");

        Socket echoSocket = null;
        PrintWriter out = null;
        BufferedReader in = null;

        try {

            echoSocket = new Socket(serverHostname, port);
            out = new PrintWriter(echoSocket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(echoSocket.getInputStream(), "UTF-8"));

            } catch (UnknownHostException e) {

                System.err.println("Don't know about host: " + serverHostname);
                System.exit(1);

            } catch (IOException e) {

                System.err.println("Couldn't get I/O for " + "the connection to: " + serverHostname);
                System.exit(1);

            }

       BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
       String userInput;

     System.out.print ("input: ");

     while ((userInput = stdIn.readLine()) != null) {

           out.println(userInput);
           System.out.println("echo: " + in.readLine());
         System.out.print ("input: ");

       }

       out.close();
       in.close();
       stdIn.close();
       echoSocket.close();

    }

}