Client kann keine Verbindung zum Server in Chat-Anwendung herstellen

Question

Ich versuche, einen Client mit dem Server zu verbinden, aber es kann keine Verbindung zu ihm herstellen. Wenn der Client gestartet wird, möchte ich, dass er auf den Server wartet. Wenn der Server gestartet wird, sollte der Client eine Verbindung herstellen und mit dem Chatten beginnen.

Auftraggeber:

import java.io.*; 
import java.net.*; 
import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*; 

public class Client extends JFrame implements Runnable { 
    private Thread t; 
    private JTextField userText; 
    private JTextArea chatwindow; 
    private ObjectOutputStream output; 
    private ObjectInputStream input; 
    private String message = ""; 
    //ip address of the server 
    private String serverIp; 
    private Socket connection; 

    //give the ip address of the server to connect 
    public Client(String host){ 
     super("Client"); 
     serverIp = host; 
     userText = new JTextField(); 
     userText.setEditable(false); 
     userText.addActionListener(new ActionListener() { 

      @Override 
      public void actionPerformed(ActionEvent event) { 
       // TODO Auto-generated method stub 
       sendMessage(event.getActionCommand()); 
       userText.setText(""); 
      } 
     }); 

     add(userText,BorderLayout.NORTH); 
     chatwindow = new JTextArea(); 
     add(new JScrollPane(chatwindow),BorderLayout.CENTER); 
     setSize(500,500); 
     setVisible(true); 
    } 

    //connect to server 
    public void run(){ 
     while(true){ 
      showMessage("attempting connection ...... "); 
      try { 
       connection = new Socket("host", 6789); 
       if(connection.isConnected()) 
        break; 
      } catch (IOException e) { 
       // TODO Auto-generated catch block 

      } 
      try { 
       Thread.sleep(5000); 
      } catch (InterruptedException e) { 
       // TODO Auto-generated catch block 

      } 

     } 
     showMessage("connected ..... \n "+connection.getInetAddress().getHostName()); 
    } 
    public void startRunning(){ 


      try{ 
       //connect to one specific server 
       //connectToServer(); 
       setupStreams(); 
       whileChatting(); 
      }catch(EOFException eofException){ 
       showMessage("Client terminate connection \n"); 
      }catch(IOException ioException){ 
       showMessage("error"); 
      }/*finally{ 
       closeCrap(); 
      }*/ 

    } 

    //connect to server 
    /*private void connectToServer() throws IOException{ 
//new Runnable() { 

      @Override 
      public void run() { 
       // TODO Auto-generated method stub 
       while(true){ 
        showMessage("attempting connection ...... "); 
        //port on the server =6789 
        try { 
         connection = new Socket("host", 6789); 
         Thread.sleep(50); 
        } catch (UnknownHostException e) { 
         // TODO Auto-generated catch block 
         //e.printStackTrace(); 
        } catch (IOException e) { 
         // TODO Auto-generated catch block 
         //e.printStackTrace(); 
        } catch (InterruptedException e) { 
         // TODO Auto-generated catch block 
         //e.printStackTrace(); 
        } 
        //connection = new Socket(InetAddress.getByName(serverIp),6789); 
        showMessage("connected ..... \n "+connection.getInetAddress().getHostName()); 
        } 
      } 
     }; 

    }*/ 

    //setup streams to send and recieve message 
    private void setupStreams() throws IOException{ 
     output = new ObjectOutputStream(connection.getOutputStream()); 
     output.flush(); 
     input = new ObjectInputStream(connection.getInputStream()); 
     showMessage("streams are now setup"); 
    } 

    //while chatting with server 
    private void whileChatting() throws IOException{ 
     ableToType(true); 
     do{ 

      try{ 
       // to read whatever sent as string 
       message = (String)input.readObject(); 
       showMessage("\n "+message); 
      }catch(ClassNotFoundException classNotFoundException){ 
       showMessage("unknow object type"); 
      } 
     }while(!message.equals("Server : END")); 
    } 

    // close the streams and sockets 
    private void closeCrap(){ 
     showMessage("\n closing crap down ....."); 
     ableToType(false); 
     try{ 

      output.close(); 
      input.close(); 
      connection.close(); 
     }catch(IOException ioException){ 
      ioException.printStackTrace(); 
     } 
    } 

    //send message to server 
    private void sendMessage(String message){ 
     try{ 
      output.writeObject("Client : "+message); 
      output.flush(); 
      showMessage("\n Client : "+message); 
     }catch(IOException ioException){ 
      chatwindow.append("error \n "); 
     } 
    } 

    //update chat window 
    private void showMessage(final String text){ 
     SwingUtilities.invokeLater(new Runnable() { 

      @Override 
      public void run() { 
       // TODO Auto-generated method stub 
       chatwindow.append(text); 
      } 
     }); 
    } 

    //permession to type in textbox 
    private void ableToType(final boolean variable){ 
     SwingUtilities.invokeLater(new Runnable() { 

      @Override 
      public void run() { 
       // TODO Auto-generated method stub 
       userText.setEditable(variable); 
      } 
     }); 
    } 
} 

Server:

import java.io.*; 
    import java.net.*; 
    import java.awt.*; 
    import java.awt.event.*; 
    import javax.swing.*; 

    public class Server extends JFrame{ 

    //that's the area you type your message before sent 
    private JTextField userText; 
    // the area that display tha conversation 
    private JTextArea chatWindow; 
    //build output streams 
    private ObjectOutputStream output; 
    //build input stream 
    private ObjectInputStream input; 
    private ServerSocket server; 
    //connection==socket 
    private Socket connection; 

    public Server(){ 
     //add title on tha top of tha winddow 
     super("Server"); 
     userText = new JTextField(); 
     //before you connect you don't allow to type anything in the message box 
     userText.setEditable(false); 
     userText.addActionListener(new ActionListener() { 

      @Override 
      public void actionPerformed(ActionEvent event) { 
       // TODO Auto-generated method stub 
       // when user write something and hit enter that method is performed 
       //to send message 
       sendMessage(event.getActionCommand()); 
       userText.setText(""); 

      } 
     }); 
     add(userText,BorderLayout.NORTH); 
     chatWindow = new JTextArea(); 
     add(new JScrollPane(chatWindow)); 
     setSize(500,500); 
     setVisible(true); 
    } 

    //setup and run the server 
    public void startRunning(){ 
     try{ 
      //port number=6789 
      //only a 100 people allow to hold and wait in the port 
      server = new ServerSocket(6789,100); 
      // this is the code you want to run it over and over again 
      while(true){ 
       try{ 
        //connect and have conversation 
        waitForConnection(); 
        //setup tha input and output streams 
        setupStreams(); 
        //send message back and forth 
        whileChatting(); 

        //exception end of connection 
       }catch(EOFException eofException){ 
        showMessage("error"); 
       }finally{ 
        closeCrap(); 
       } 
      } 

     }catch(IOException ioException){ 
      ioException.printStackTrace(); 
     } 
    } 

    //wait for connection,then display connection information 
    private void waitForConnection(){ 
     showMessage("wainting for some one to connect....\n"); 
     //connection is the socket that server accept it once someone want to connect 
     try { 
      connection = server.accept(); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
     //return the address and tha ip adress 
     showMessage("now connected to "+connection.getInetAddress().getHostName()); 
    } 

    //get stream to send and receive date 
    private void setupStreams() throws IOException{ 
     //create the path way to another computer want to connect to 
     output = new ObjectOutputStream(connection.getOutputStream()); 
     output.flush(); 
     input = new ObjectInputStream(connection.getInputStream()); 
     showMessage(" streams are now setup"); 

    } 

    //during the chat conversation 
    private void whileChatting() throws IOException{ 
     String message = "You are now connected"; 
     sendMessage(message); 
     // let the user type and chatting 
     ableToType(true); 
     do{ 
      //have a conversation 
      try{ 
       //read a message and make sure it a string 
       message = (String)input.readObject(); 
       showMessage("\n"+message); 
      }catch(ClassNotFoundException classNotFoundException){ 
       showMessage("what is that O.o wired "); 
      } 
     }while(!message.equals("Client : END")); 
    } 

    //close streams and sockets after you done chatting 
    private void closeCrap(){ 
     showMessage("\n end of cpnnection ...... \n"); 
     ableToType(false); 
     try{ 
      //close the streams 
      output.close(); 
      input.close(); 
      //close the socket 
      connection.close(); 
     }catch(IOException ioException){ 
      ioException.printStackTrace(); 

     } 
    } 

    //send a message to client 
    private void sendMessage(String message){ 
     try{ 
      //send a message throw the output stream "user name" 
      output.writeObject("Server : "+message); 

      output.flush(); 
      showMessage("\n Server : "+message); 
     }catch(IOException ioException){ 
      //put it in the chat area 
     chatWindow.append("\n error O.o that message can't be sent"); 
     } 
    } 

    //update chat window 
    private void showMessage(final String text){ 
     //allow to create a thread -update chat window- 
     SwingUtilities.invokeLater(new Runnable() { 

      @Override 
      public void run() { 
       // TODO Auto-generated method stub 
       // add a message to the chat wondow 
       chatWindow.append(text); 
      } 
     }); 
    } 

    // allow client to type 
    private void ableToType(final boolean variable){ 
     SwingUtilities.invokeLater(new Runnable() { 

      @Override 
      public void run() { 
       // TODO Auto-generated method stub 
       userText.setEditable(variable); 
      } 
     }); 

    } 
} 

cientChat:

 import javax.swing.JFrame; 
    public class CientChat { 

    public static void main(String[] args) { 
     // TODO Auto-generated method stub 


     //127.0.0.1 means localhost 
     Client testClient = new Client ("127.0.0.1"); 
     testClient.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     testClient.run(); 
     testClient.startRunning(); 
    } 

} 

ServerChat:

import javax.swing.JFrame; 
public class ServerChat { 

    public static void main(String[] args) { 
     // TODO Auto-generated method stub 

     Server test = new Server(); 
     test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     test.startRunning(); 
    } 

} 

Answer 1

dies:

connection = new Socket("host", 6789); 

nicht der richtige Weg ist, Verbindung zu starten, sollten Sie entweder "localhost" oder die IP-"127.0.0.1"

versuchen stattdessen versuchen:

connection = new Socket("localhost", 6789);