java如何向服务器获取字符串（jave.net/sockets）

我一直在构建一个聊天服务器来学习线程和套接字的使用。我使用了head first java作为指导（我仍然对一些事情感到困惑，这就是为什么我会有这个问题：D），下面的代码就是我所拥有的

如果您阅读我的代码，您将看到我的客户端通过单击“连接”按钮连接到服务器。当他们这样做时，会弹出一个新的jframe，询问他们在聊天会话中的首选名称。当他们输入时，它会保存在客户机代码中的字符串中。我的问题是，如何将此名称传递给服务器，并使其在每次客户端发送消息时，都显示在消息之前

谢谢你的帮助

（另外，如果有人知道一个好的链接，可以解释套接字以及如何通过线程进行套接字/客户端交互，那就太好了！）

服务器代码：

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


public class GameServerOne {
    ArrayList clientOutputStreams;
    String clientName;
    private class ClientThreadHandler implements Runnable {
        BufferedReader clientIncomingReader;
        Socket socket1;
        public ClientThreadHandler(Socket clientSocket2) {
            try {
                socket1 = clientSocket2;
                InputStreamReader clientInputReader = new InputStreamReader(socket1.getInputStream());
                clientIncomingReader = new BufferedReader(clientInputReader);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        public void run() {
            String message;
            try {
                while ((message = clientIncomingReader.readLine()) != null) {
                    tellEveryone(message);
                }
            } catch (Exception e) { 
                e.printStackTrace();
            }
        }
    }
    public void tellEveryone(String message) {
        Iterator it = clientOutputStreams.iterator();
        while(it.hasNext()) {
            try {
                PrintWriter writer = (PrintWriter) it.next();
                writer.println(message);
                writer.flush();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    public void setUpServer() {
        clientOutputStreams = new ArrayList();
        try {
            ServerSocket gameSocket = new ServerSocket(5151);
            //System.out.println("Server Connected");

            while (true) {
                Socket clientSocket = gameSocket.accept();
                PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
                writer.println("User connected");
                writer.flush();
                clientOutputStreams.add(writer);
                Thread t = new Thread(new ClientThreadHandler(clientSocket));
                t.start();


            }

        } catch (Exception ex) {
                ex.printStackTrace();
        }
    }
    public static void main(String[] args) {
        new GameServerOne().setUpServer();
    }


}

客户端代码：

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


public class GameClientOne {
    Socket gameSocket;
    JFrame inputNameFrame;
    JFrame clientFrame;
    JTextArea chatArea;
    JTextField messageInput;
    BufferedReader gameChatReader;
    PrintWriter gameChatWriter;
    JTextField nameField;
    boolean sessionNamePicked = false;
    String userSessionName;
    BufferedReader gameBufferedReader;



    public GameClientOne () {
        setUpGUI();
    }

    public void setUpGUI() {
        clientFrame = new JFrame("Game Window");
        JPanel mainPanel = new JPanel(new BorderLayout());
        JPanel southPanel = new JPanel(new BorderLayout());
        JPanel centerPanel = new JPanel(new BorderLayout());
        chatArea = new JTextArea();
        chatArea.setWrapStyleWord(true);
        chatArea.setLineWrap(true);
        chatArea.setEditable(false);
        JScrollPane chatScroller = new JScrollPane(chatArea);
        messageInput = new JTextField();
        messageInput.addKeyListener(new MessageInputFieldListener());
        JButton sendButton = new JButton("Send");
        sendButton.addActionListener(new SendButtonListener());
        JPanel westPanel = new JPanel(/*new GridLayout(20, 1)*/);
        JPanel eastPanel = new JPanel();
        JButton connectButton = new JButton("Connect");
        connectButton.addActionListener(new ConnectButtonListener());
        connectButton.setPreferredSize(new Dimension(100, 28));
        JPanel northPanel = new JPanel(new FlowLayout());
        JLabel northTitleLabel = new JLabel("Game Screen");
        westPanel.add(connectButton);
        chatScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS) ; 
        chatScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);



        northPanel.add(northTitleLabel);
        centerPanel.add(BorderLayout.CENTER, chatScroller);
        southPanel.add(BorderLayout.CENTER, messageInput);
        southPanel.add(BorderLayout.EAST, sendButton);
        mainPanel.add(BorderLayout.SOUTH, southPanel);
        mainPanel.add(BorderLayout.CENTER, centerPanel);
        mainPanel.add(BorderLayout.WEST, westPanel);
        mainPanel.add(BorderLayout.EAST, eastPanel);
        mainPanel.add(BorderLayout.NORTH, northPanel);

        clientFrame.add(mainPanel);
        clientFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        clientFrame.setSize(450, 600);
        clientFrame.setVisible(true);
        messageInput.requestFocusInWindow();

    }
    public void setUpInputNameFrame() {
        inputNameFrame = new JFrame("Insert Name");
        JPanel mainPanel = new JPanel(new BorderLayout());
        nameField = new JTextField();
        nameField.addKeyListener(new NameFieldListener());
        JButton submitButton = new JButton("Submit");
        submitButton.addActionListener(new SubmitButtonListener());
        JLabel inputNameLabel = new JLabel("Please pick a name for the chat session");
        JPanel northPanel = new JPanel(new FlowLayout());
        JPanel southPanel = new JPanel(new BorderLayout());
        northPanel.add(inputNameLabel);
        southPanel.add(BorderLayout.CENTER, nameField);
        southPanel.add(BorderLayout.EAST, submitButton);
        mainPanel.add(BorderLayout.NORTH, northPanel);
        mainPanel.add(BorderLayout.SOUTH, southPanel);
        inputNameFrame.add(mainPanel);
        inputNameFrame.setSize(300, 150);
        inputNameFrame.setVisible(true);
        nameField.requestFocusInWindow();
    }

    public void connectToGameServer() {
            try {

                gameSocket = new Socket("127.0.0.1", 5151);
                InputStreamReader gameSocketReader = new InputStreamReader(gameSocket.getInputStream());
                gameBufferedReader = new BufferedReader(gameSocketReader);
                gameChatWriter = new PrintWriter(gameSocket.getOutputStream());
                chatArea.append("Connected with name: " + userSessionName + "\n");
                Thread incomingTextThread = new Thread(new IncomingTextReader());
                incomingTextThread.start();
                //System.out.println("Connected to Game");
            } catch (Exception e) {
                System.out.println("Could not connect to game...");
                e.printStackTrace();
            }

    }

    //ALL LISTENER CLASSES BELOW HERE
    //main chat page listeners
    private class ConnectButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if (!sessionNamePicked) {
                setUpInputNameFrame();
            } else {
                chatArea.append("You already connected!\n");
            }


        }
    }
    private class SendButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if (!sessionNamePicked)  {
                chatArea.append("Please connect first\n");
                messageInput.setText("");
                messageInput.requestFocusInWindow();
            } else {
                try {
                    gameChatWriter.println(messageInput.getText());
                    gameChatWriter.flush();
                } catch (Exception ex2) {
                    ex2.printStackTrace();
                }
                //chatArea.append(userSessionName + ": " + messageInput.getText() + "\n");
                messageInput.setText("");
                messageInput.requestFocusInWindow();
            }
        }
    }
    private class MessageInputFieldListener implements KeyListener {
        public void keyPressed(KeyEvent e) {

        }
        public void keyTyped(KeyEvent e) {

        }
        public void keyReleased(KeyEvent e) {
            if (e.getKeyCode() == KeyEvent.VK_ENTER) {
                if (!sessionNamePicked)  {
                    chatArea.append("Please connect first\n");
                    messageInput.setText("");
                } else {
                    try {
                        gameChatWriter.println(messageInput.getText());
                        gameChatWriter.flush();
                    } catch (Exception ex2) {
                        ex2.printStackTrace();
                    }
                    //chatArea.append(userSessionName + ": " + messageInput.getText() + "\n");
                    messageInput.setText("");
                }
            }
        }
    }

    //pick chat session name listeners: nameField/submitButton
    private class NameFieldListener implements KeyListener {
        public void keyPressed(KeyEvent e) {

        }
        public void keyTyped(KeyEvent e) {

        }
        public void keyReleased(KeyEvent e) {
                if (!nameField.getText().isEmpty() && e.getKeyCode() == KeyEvent.VK_ENTER) {
                    userSessionName = nameField.getText();
                    sessionNamePicked = true;
                    connectToGameServer();
                    inputNameFrame.dispose();
                    messageInput.requestFocusInWindow();
                }

        }
    }
    private class SubmitButtonListener implements ActionListener {
        public void actionPerformed (ActionEvent e) {
            if (!nameField.getText().isEmpty()) {
                userSessionName = nameField.getText();
                sessionNamePicked = true;
                connectToGameServer();
                inputNameFrame.dispose();
                messageInput.requestFocusInWindow();
            }
        }
    }
    //Runnable implementation for threads
    private class IncomingTextReader implements Runnable {
        public void run() {
            String incomingMessage;
            try {
                while ((incomingMessage = gameBufferedReader.readLine()) != null) {
                    chatArea.append(incomingMessage + "\n");
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }


    public static void main(String[] args) {
        GameClientOne gameClient = new GameClientOne();
    }


}

---

如果您不想像现在这样只发送一条消息，那么您需要一个协议来决定如何处理接收到的字符串，而不仅仅是将它发送给所有其他客户端

例如，在客户端发送客户端名称时，您可以写name:（client's name），然后在服务器上，您将在：处拆分字符串，并检查第一部分是否为name，如果是，则将客户端名称设置为字符串的其余部分。您应该考虑可能还需要发送哪些其他类型的数据，并设计一个适用于该数据的协议

以下是如何执行上述操作的示例：

在客户端上，您可以添加一行

gameChatWriter。连接完成后立即写入（“名称：”+NAME）

（当然先创建名称）。然后在服务器上，在收到消息时，不要调用

tellEveryone（message）

，而是创建一个名为processInput的方法并调用它，它可能如下所示：

private void processInput(String message){
    String[] commands=message.split(':');
    if(commands[0].equals("NAME")){
        clientName=commands[1];
    }
    else{
        tellEveryone(message);
    }
}

现在，您只有一个

stringclientname

，并且您显然需要与其他客户机进行对话，因此我建议将线程处理程序设置为一个单独的类，您可以为每个客户机实例化该类，并可以保存类似的内容

---

在这项工作完成后，您还可以创建一个单独的方法来编写要发送到客户端或服务器的其他内容，以及一个在客户端处理输入的方法。希望这能有所帮助。

请看示例和。谢谢，我现在来看：）如果您不介意我打扰您一分钟，您能给我一个如何执行此协议的快速示例吗。我是新手，需要一些帮助