Knock Knock 带有服务器和 UI 的应用程序

Question

我正在创建一个简单的 Knock Knock 应用程序（套接字编程），其中有一个本地主机服务器和一个客户端。程序很简单，服务器会讲敲门笑话，这就是它应该如何进行，

Server: Knock Knock
Client: Who's there?
Server: Turnip.
Client: Turnip Who?
Server: Turnip the heat.

所以这就是程序应该进行。但问题是我的 GUI 没有显示任何消息。在我的文本区域。这是我的代码。

服务器：

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

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

        ServerSocket serverSocket = null;
        try {
            serverSocket = new ServerSocket(4444);
        } catch (IOException e) {
            System.err.println("Could not listen on port: 4444.");
            System.exit(1);
        }

        Socket clientSocket = null;
        try {
            clientSocket = serverSocket.accept();
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        }

        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(
                new InputStreamReader(
                clientSocket.getInputStream()));
        String inputLine, outputLine;
        KnockKnockProtocol kkp = new KnockKnockProtocol();

        outputLine = kkp.processInput(null);
        out.println(outputLine);

        while ((inputLine = in.readLine()) != null) {
             outputLine = kkp.processInput(inputLine);
             out.println(outputLine);
             if (outputLine.equals("Bye."))
                break;
        }
        out.close();
        in.close();
        clientSocket.close();
        serverSocket.close();
    }
}

KnockKnockProtocol

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

public class KnockKnockProtocol {
    private static final int WAITING = 0;
    private static final int SENTKNOCKKNOCK = 1;
    private static final int SENTCLUE = 2;
    private static final int ANOTHER = 3;

    private static final int NUMJOKES = 5;

    private int state = WAITING;
    private int currentJoke = 0;

    private String[] clues = { "Turnip", "Little Old Lady", "Atch", "Who", "Who" };
    private String[] answers = { "Turnip the heat, it's cold in here!",
                                 "I didn't know you could yodel!",
                                 "Bless you!",
                                 "Is there an owl in here?",
                                 "Is there an echo in here?" };

    public String processInput(String theInput) {
        String theOutput = null;

        if (state == WAITING) {
            theOutput = "Knock! Knock!";
            state = SENTKNOCKKNOCK;
        } else if (state == SENTKNOCKKNOCK) {
            if (theInput.equalsIgnoreCase("Who's there?")) {
                theOutput = clues[currentJoke];
                state = SENTCLUE;
            } else {
                theOutput = "You're supposed to say \"Who's there?\"! " +
                "Try again. Knock! Knock!";
            }
        } else if (state == SENTCLUE) {
            if (theInput.equalsIgnoreCase(clues[currentJoke] + " who?")) {
                theOutput = answers[currentJoke] + " Want another? (y/n)";
                state = ANOTHER;
            } else {
                theOutput = "You're supposed to say \"" + 
                clues[currentJoke] + 
                " who?\"" + 
                "! Try again. Knock! Knock!";
                state = SENTKNOCKKNOCK;
            }
        } else if (state == ANOTHER) {
            if (theInput.equalsIgnoreCase("y")) {
                theOutput = "Knock! Knock!";
                if (currentJoke == (NUMJOKES - 1))
                    currentJoke = 0;
                else
                    currentJoke++;
                state = SENTKNOCKKNOCK;
            } else {
                theOutput = "Bye.";
                state = WAITING;
            }
        }
        return theOutput;
    }
}

客户端。

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


public class KnockKnockClient {

    public String fromServer;
    public String fromUser;

    public void Client() throws IOException {

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


        try {
            kkSocket = new Socket("127.0.0.1", 4444);
            out = new PrintWriter(kkSocket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(kkSocket.getInputStream()));
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host: 127.0.0.1");
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to: 127.0.0.1");
            System.exit(1);
        }

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

        while ((fromServer = in.readLine()) != null) {
            System.out.println("Server: " + fromServer);

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

            fromUser = stdIn.readLine();
        if (fromUser != null) {
                System.out.println("Client: " + fromUser);
                out.println(fromUser);
        }
        }

        out.close();
        in.close();
        stdIn.close();
        kkSocket.close();
    }


}

UI

 import java.awt.event.ActionListener;



    public class KnockKnockWindow extends JFrame {

        JTextArea clientTextArea;
        JTextArea serverTextArea;
        JButton submitButton;


        public KnockKnockWindow() {

            super("Chat Window");
            setVisible(true);
            setDefaultCloseOperation(EXIT_ON_CLOSE);
            setLocationRelativeTo(null);
            setSize(420,228);

            getContentPane().setLayout(null);

            clientTextArea = new JTextArea();
            clientTextArea.setBounds(10, 118, 278, 51);
            getContentPane().add(clientTextArea);


            serverTextArea = new JTextArea();
            serverTextArea.setBounds(10, 11, 278, 96);
            getContentPane().add(serverTextArea);

            submitButton = new JButton("Submit");
            submitButton.setBounds(298, 118, 89, 51);
            getContentPane().add(submitButton);
        }


        public void setServerText(String fromServer){
            serverTextArea.setText(fromServer);
        }

        public void setClientText(String fromClient){
            clientTextArea.setText(fromClient);
        }

        public String returnClientText(){
            return clientTextArea.getText();
        }

        public void addSubmitListener(ActionListener sub){
            submitButton.addActionListener(sub);
        }

    }   



The Controller


import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;


public class KnockKnockController {

    private KnockKnockClient client;
    private KnockKnockWindow window;

    public KnockKnockController(KnockKnockClient client, KnockKnockWindow window){
        this.client = client;
        this.window = window;

        window.addSubmitListener(new SubmitListener());
        window.setServerText(client.fromServer);
    }

    public class SubmitListener implements ActionListener{

        public void actionPerformed(ActionEvent arg0) {
            client.fromUser = window.returnClientText();
        }
    }
}

和主应用程序

import javax.swing.JFrame;

public class KnockTest extends JFrame{

    public static void main (String[] args){
        KnockKnockClient kkcl = new KnockKnockClient();
        KnockKnockWindow kkw = new KnockKnockWindow();
        KnockKnockController kkc = new KnockKnockController(kkcl,kkw);
    }
}

我们将首先运行服务器，然后是主应用程序。

但为什么我没有收到服务器发送的任何消息？当我点击开始时。服务器的文本区域应该显示 KnockKnock。但它似乎没有显示，有什么想法吗？抱歉，代码很长，但我不知道在这里缩短它们。因为我知道其中大部分都很重要

Answer 1

正如您所说， while 循环只是获取文本并将其打印到控制台，您到底在哪里打印到文本区域。

// Put this code somewhere in the Client class so that when it receives something,
// it can be added to the `JTextArea`
while ((fromServer = in.readLine()) != null) 
{
    // You seems like missed the part that sends it to the textArea
    System.out.println("Server: " + fromServer);
    // Here send the received thing to your textarea, which goes something like this
    String str = "Server : " + fromServer + "\n";
    tarea.append(str);

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

    // You can remove this part and put it inside the textField's actionPerformed method. 
    fromUser = stdIn.readLine();
    if (fromUser != null) 
    {
        System.out.println("Client: " + fromUser);
        out.println(fromUser);
    }
}

全新编辑：

只需从命令提示符启动 KnockKnockServer，而不是从扩展 JFrame 的类启动。只需简单地编写 java KnockKnockServer，即可在命令提示符下运行您的服务器，现在在新的命令提示符下编译我给您的这个类并像 java KnockKnockClient 一样运行它，您会发现它并没有完全工作。

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


public class KnockKnockClient extends JFrame
{

    public String fromServer;
    public String fromUser;
    // Added by me.--------------------
    private JTextArea tarea;
    private JTextField tfield;
    private JScrollPane spane;
    private PrintWriter out = null;
    /*------------------------------------*/

    public void Client() throws IOException 
    {
        Socket kkSocket = null;
        //PrintWriter out = null;  Shifted this to the instance variable
        BufferedReader in = null;

        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
        try {
            kkSocket = new Socket("127.0.0.1", 4444);
            out = new PrintWriter(kkSocket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(kkSocket.getInputStream()));
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host: 127.0.0.1");
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to: 127.0.0.1");
            System.exit(1);
        }

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);

        JPanel contentPane = new JPanel();

        tarea = new JTextArea(10, 10);
        spane = new JScrollPane(tarea);
        tarea.setLineWrap(true);
        tfield = new JTextField(10);

        tfield.requestFocusInWindow();

        contentPane.setLayout(new BorderLayout());
        contentPane.add(spane, BorderLayout.CENTER);
        contentPane.add(tfield, BorderLayout.PAGE_END);

        setContentPane(contentPane);
        pack();
        setVisible(true); 

        Thread receiveMessage = new Thread(new ReceiveChat(in, stdIn, out));    
        receiveMessage.start();



        tfield.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                // Here you will send it to the server side too, put that code here
                fromUser = tfield.getText() + "\n";
                if (fromUser != null) 
                {
                    System.out.println("Client: " + fromUser);
                    tarea.append(fromUser);
                    out.println(fromUser);
                    tfield.setText("");
                }
            }
        });
        //out.close();
        //in.close();
        //stdIn.close();
        //kkSocket.close();
     }    

     private class ReceiveChat implements Runnable
     {
        private BufferedReader in;
        private BufferedReader stdIn;
        private PrintWriter out;

        public ReceiveChat(BufferedReader in, BufferedReader stdIn, PrintWriter out)
        {
            this.in = in;
            this.stdIn = stdIn;
            this.out = out;
        }

        public void run()
        {
            try
            {
                while ((fromServer = in.readLine()) != null) {
                //System.out.println("Server: " + fromServer);
                String str = "Server : " + fromServer + "\n";
                tarea.append(str);
                tarea.setCaretPosition(tarea.getDocument().getLength());

                if (fromServer.equals("Bye."))
                    break;
                /*Commented out by me.*/
                /*fromUser = stdIn.readLine();
                if (fromUser != null) {
                    System.out.println("Client: " + fromUser);
                    out.println(fromUser);
                }   */
                }
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
        }
     }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                KnockKnockClient client = new KnockKnockClient();
                try
                {
                    client.Client();
                }
                catch(Exception e)
                {
                    e.printStackTrace();
                }
            }
        });
    }
}

只需让 KnockKnockServer 类的 while 循环如下所示：

while ((inputLine = in.readLine()) != null) 
{
    if (inputLine.length() > 0)
    {
        outputLine = kkp.processInput(inputLine);            
        out.println(outputLine);
        if (outputLine.equals("Bye."))
            break;
    }   
}

这将使其按预期工作。