采用Java Socket实现基于TCP方式的客户服务器聊天程序

本文讲演示如何通过Java Socket建立C/S方式的聊天程序。实现的功能

主要包括如下几个方面：

1. 用户登录，在线用户列表刷新

2.客户端与服务器的TCP连接，实现消息的发送与接受

3.Java Swing与多线程编程技巧

一个整体的Class关系图如下：

程序实现的服务器端UI如下：

一个JList组件用来显示在线的所有用户，一个JTextArea组件用来显示所有消息

记录。所有消息必须通过服务器端转发。点击【start】按钮启动服务器端监听

默认监听端口为9999。

启动服务器端的Action中的代码如下：

 Thread startThread = new Thread(new Runnable() {                  public void run() {                   startServer(9999);                  }              });   startThread.start();   startBtn.setEnabled(false);   shutDownBtn.setEnabled(true);

startServer（）的代码如下：

private void startServer(int port) {   try {    serverSocket = new ServerSocket(port);    System.out.println("Server started at port :" + port);    while(true) {     Socket client = serverSocket.accept(); // blocked & waiting for income socket     System.out.println("Just connected to " + client.getRemoteSocketAddress());     DataInputStream bufferedReader = new DataInputStream(client.getInputStream());     byte[] cbuff = new byte[256];     int size = bufferedReader.read(cbuff);     char[] charBuff = convertByteToChar(cbuff, size);     String userName = String.valueOf(charBuff);     ChatServerClientThread clentThread = new ChatServerClientThread(userName, client, this);     clientList.add(clentThread);     userNameList.add(userName);     clentThread.start();     updateUserList();    }     } catch (IOException e) {    e.printStackTrace();   }  }

简单协议规则：

1.      任何消息发送完以后系统自动加上结束标志EOF

2.      接受到用户消息以后通过解析EOF来完成消息传递

3.      自动发送更新用户列表到所有客户端当有新客户登入时

为什么我要实现上述简单协议，其实任何网络通信都是基于协议实现

只有基于协议实现才可控制，可检查。协议是网络通信的最重要一环。

客户端UI设计如下：

一个自定义的JPanel实现背景渐进颜色填充。

- Message组件用来接受用户输入的聊天信息

- Friend List 会自动刷新用户列表，当有新用户登录时候

- History Record用来显示聊天记录

- 【Connect】点击连接到Server端，前提是必须填写设置中全部，默认

    的机器IP为127.0.0.1端口为9999

- 【send】按钮点击会发送用户输入的消息到指定的其它客户端。如果

    没有选择用户，则发送到服务器端。

-  一次发送消息的大小不得大于200个字节。

完整的客户端代码如下：

package com.gloomyfish.socket.tutorial.chat;    import java.awt.BorderLayout;  import java.awt.FlowLayout;  import java.awt.GridLayout;  import java.awt.event.ActionEvent;  import java.awt.event.ActionListener;  import java.io.IOException;  import java.net.InetSocketAddress;  import java.net.Socket;  import java.net.SocketAddress;    import javax.swing.BorderFactory;  import javax.swing.JButton;  import javax.swing.JCheckBox;  import javax.swing.JFrame;  import javax.swing.JLabel;  import javax.swing.JList;  import javax.swing.JOptionPane;  import javax.swing.JPanel;  import javax.swing.JPasswordField;  import javax.swing.JScrollPane;  import javax.swing.JTextArea;  import javax.swing.JTextField;    import com.gloomyfish.custom.swing.ui.CurvedGradientPanel;    public class ChatClient extends JFrame implements ActionListener {   public final static String CONNECT_CMD = "Connect";   public final static String DISCONNECT_CMD = "Disconnect";   public final static String SEND_CMD = "Send";   public final static String END_FLAG = "EOF";     /**    *     */   private static final long serialVersionUID = 5837742337463099673L;   private String winTitle;   private JLabel userLabel;   private JLabel passwordLabel;   private JLabel ipLabel;   private JLabel portLabel;      // text field   private JTextField userField;   private JPasswordField passwordField;   private JTextField ipField;   private JTextField portField;      private JList friendList;   private JTextArea historyRecordArea;   private JTextArea chatContentArea;      // buttons   private JButton connectBtn;   private JButton disConnectBtn;   private JButton sendBtn;   private JCheckBox send2AllBtn;      // socket   private Socket mSocket;   private SocketAddress address;   private ChatClientThread m_client;      public ChatClient() {    super("Chat Client");    initComponents();    setupListener();   }      private void initComponents() {    JPanel settingsPanel = new CurvedGradientPanel();    JPanel chatPanel = new CurvedGradientPanel();    GridLayout gy = new GridLayout(1,2,10,2);    getContentPane().setLayout(gy);    getContentPane().add(settingsPanel);    getContentPane().add(chatPanel);        // set up settings info    settingsPanel.setLayout(new BorderLayout());    settingsPanel.setOpaque(false);    JPanel gridPanel = new JPanel(new GridLayout(4, 2));    gridPanel.setBorder(BorderFactory.createTitledBorder("Server Settings & User Info"));    gridPanel.setOpaque(false);    userLabel = new JLabel("User Name:");    passwordLabel = new JLabel("User Password:");    ipLabel = new JLabel("Server IP Address:");    portLabel = new JLabel("Server Port");    userLabel.setOpaque(false);    passwordLabel.setOpaque(false);    ipLabel.setOpaque(false);    portLabel.setOpaque(false);    userField = new JTextField();    passwordField = new JPasswordField();    ipField = new JTextField();    portField = new JTextField();    connectBtn = new JButton(CONNECT_CMD);    disConnectBtn = new JButton(DISCONNECT_CMD);    JPanel btnPanel = new JPanel();    btnPanel.setOpaque(false);    btnPanel.setLayout(new FlowLayout());    btnPanel.add(connectBtn);    btnPanel.add(disConnectBtn);        gridPanel.add(userLabel);    gridPanel.add(userField);    gridPanel.add(passwordLabel);    gridPanel.add(passwordField);    gridPanel.add(ipLabel);    gridPanel.add(ipField);    gridPanel.add(portLabel);    gridPanel.add(portField);    friendList = new JList();    JScrollPane friendPanel = new JScrollPane(friendList);    friendPanel.setOpaque(false);    friendPanel.setBorder(BorderFactory.createTitledBorder("Friend List:"));    settingsPanel.add(btnPanel, BorderLayout.SOUTH);    settingsPanel.add(gridPanel, BorderLayout.NORTH);    settingsPanel.add(friendPanel,BorderLayout.CENTER);        chatPanel.setLayout(new GridLayout(3,1));    chatPanel.setOpaque(false);    historyRecordArea = new JTextArea();    JScrollPane histroyPanel = new JScrollPane(historyRecordArea);    histroyPanel.setBorder(BorderFactory.createTitledBorder("Chat History Record:"));    histroyPanel.setOpaque(false);    chatContentArea = new JTextArea();    JScrollPane messagePanel = new JScrollPane(chatContentArea);    messagePanel.setBorder(BorderFactory.createTitledBorder("Message:"));    messagePanel.setOpaque(false);    // chatPanel.add(friendPanel);    chatPanel.add(histroyPanel);    chatPanel.add(messagePanel);    sendBtn = new JButton(SEND_CMD);    send2AllBtn = new JCheckBox("Send to All online Users");    send2AllBtn.setOpaque(false);    JPanel sendbtnPanel = new JPanel();    sendbtnPanel.setOpaque(false);    sendbtnPanel.setLayout(new FlowLayout());    sendbtnPanel.add(sendBtn);    sendbtnPanel.add(send2AllBtn);    chatPanel.add(sendbtnPanel);   }      private void setupListener() {    connectBtn.addActionListener(this);    disConnectBtn.addActionListener(this);    sendBtn.addActionListener(this);    disConnectBtn.setEnabled(false);   }      /**    * <p></p>    *     * @param content - byte array    * @param bsize - the size of bytes    */   public synchronized void handleMessage(char[] content, int bsize) {    // char[] inputMessage = convertByteToChar(content, bsize);    String receivedContent = String.valueOf(content);    int endFlag = receivedContent.indexOf(END_FLAG);    receivedContent = receivedContent.substring(0, endFlag);    System.out.println("Client " + userField.getText() + " Message:" + receivedContent);    if(receivedContent.contains("#")) {     String[] onlineUserList = receivedContent.split("#");     friendList.setListData(onlineUserList);    } else {     // just append to chat history record...     appendHistoryRecord(receivedContent + "\r\n");    }   }      public synchronized void appendHistoryRecord(String record) {    historyRecordArea.append(record);   }      private String getSelectedUser() {    int index = friendList.getSelectedIndex();    if(index >= 0) {    String user = (String)friendList.getSelectedValue();    return user;    } else {     return "Server";    }   }     // private char[] convertByteToChar(byte[] cbuff, int size) {  //  char[] charBuff = new char[size];  //  for(int i=0; i<size; i++) {  //   charBuff[i] = (char)cbuff[i];  //  }  //  return charBuff;  // }      public void setTitle(String title) {    winTitle = title;    super.setTitle(winTitle);   }      public String getTitle() {    return super.getTitle();   }      public static void main(String[] args) {    ChatClient client = new ChatClient();    client.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    client.pack();    client.setVisible(true);   }     @Override   public void actionPerformed(ActionEvent e) {    if(SEND_CMD.equals(e.getActionCommand())) {     String chatContent = chatContentArea.getText();     if(checkNull(chatContent)) {      JOptionPane.showMessageDialog(this, "Please enter the message at least 6 characters!");      return;     } else if(chatContent.getBytes().length > 200) {      JOptionPane.showMessageDialog(this, "The length of the message must be less than 200 characters!");      return;     }     try {      m_client.dispatchMessage(getSelectedUser() + "#" + chatContent);      m_client.dispatchMessage(END_FLAG);      appendHistoryRecord("me :" + chatContent + "\r\n");      chatContentArea.setText(""); // try to clear user enter......     } catch (IOException e1) {      e1.printStackTrace();     }    } else if(DISCONNECT_CMD.equals(e.getActionCommand())) {     enableSettingsUI(true);    } else if(CONNECT_CMD.equals(e.getActionCommand())) {     String serverHostName = ipField.getText();     String portStr = portField.getText();     String userName = userField.getText();     char[] password = passwordField.getPassword();     System.out.println("Password = " + password.length);     if(checkNull(serverHostName) || checkNull(portStr) || checkNull(userName)) {      JOptionPane.showMessageDialog(this, "Please enter user name, server host name, server port!");      return;     }     setTitle("Chat Client-" + userName);     address = new InetSocketAddress(serverHostName, Integer.parseInt(portStr));     mSocket = new Socket();     try {      mSocket.connect(address);      m_client = new ChatClientThread(this, mSocket);      m_client.dispatchMessage(userName); // send user name      // m_client.dispatchMessage(END_FLAG); // send end flag      m_client.start();      enableSettingsUI(false);     } catch (IOException ioe) {      ioe.printStackTrace();     }         }   }      private void enableSettingsUI(boolean enable) {    ipField.setEditable(enable);    portField.setEnabled(enable);    userField.setEditable(enable);    passwordField.setEnabled(enable);    connectBtn.setEnabled(enable);    disConnectBtn.setEnabled(!enable);   }      private boolean checkNull(String inputString) {    if(inputString ==  null || inputString.length() == 0) {     return true;    } else {     return false;    }   }    }

客户端SOCKET通信线程的代码如下：

package com.gloomyfish.socket.tutorial.chat;    import java.io.DataInputStream;  import java.io.DataOutputStream;  import java.io.IOException;  import java.net.Socket;    public class ChatClientThread extends Thread {   private ChatClient _mClient;   private Socket _mSocket;   private DataOutputStream dos;      public ChatClientThread(ChatClient cclient, Socket socket) {    this._mClient = cclient;    this._mSocket = socket;   }      public void run() {    try {     DataInputStream bufferedReader = new DataInputStream(_mSocket.getInputStream());     byte[] cbuff = new byte[256];     char[] tbuff = new char[256];     int size = 0;     int byteCount = 0;     int length = 0;     while(true) {      if((size = bufferedReader.read(cbuff))> 0) {       char[] temp = convertByteToChar(cbuff, size);       length = temp.length;       if((length + byteCount) > 256) {        length = 256 - byteCount;       }       System.arraycopy(temp, 0, tbuff, byteCount, length);       byteCount += size;       if(String.valueOf(tbuff).indexOf(ChatClient.END_FLAG) > 0) {        _mClient.handleMessage(tbuff, byteCount);        byteCount = 0;        clearTempBuffer(tbuff);       }      }     }    } catch (IOException e) {     e.printStackTrace();    }   }      private void clearTempBuffer(char[] tbuff) {    for(int i=0; i<tbuff.length; i++) {     tbuff[i] = ' ';    }   }      private char[] convertByteToChar(byte[] cbuff, int size) {    char[] charBuff = new char[size];    for(int i=0; i<size; i++) {     charBuff[i] = (char)cbuff[i];    }    return charBuff;   }      public synchronized void dispatchMessage(String textMsg) throws IOException {    if(dos == null) {     dos = new DataOutputStream(_mSocket.getOutputStream());    }    byte[] contentBytes = textMsg.getBytes();    dos.write(contentBytes, 0, contentBytes.length);   }  }

服务器端的消息转发代码如下：

 public synchronized void dispatchMessage(String[] keyValue, String userName) throws IOException {    chatArea.append(userName + " to " + keyValue[0] + " : " + keyValue[1] + "\r\n");    for(ChatServerClientThread client : clientList) {     if(client.getUserName().equals(keyValue[0])) {      client.dispatchMessage(userName + " says: " + keyValue[1]);      client.dispatchMessage(END_FLAG);      break;     }    }   }

服务器端的客户端线程run方法的代码如下：

public void run() {   System.out.println("start user = " + userName);   try {    DataInputStream bufferedReader = new DataInputStream(userSocket.getInputStream());    byte[] cbuff = new byte[256];    char[] tbuff = new char[256];    int size = 0;    int byteCount = 0;    int length = 0;    while(true) {     if((size = bufferedReader.read(cbuff))> 0) {      char[] temp = convertByteToChar(cbuff, size);      length = temp.length;      if((length + byteCount) > 256) {       length = 256 - byteCount;      }      System.arraycopy(temp, 0, tbuff, byteCount, length);      byteCount += size;      if(String.valueOf(tbuff).indexOf(ChatServer.END_FLAG) > 0) {       String receivedContent = String.valueOf(tbuff);       int endFlag = receivedContent.indexOf(ChatServer.END_FLAG);       receivedContent = receivedContent.substring(0, endFlag);       String[] keyValue = receivedContent.split("#");       if(keyValue.length > 1) {        server.dispatchMessage(keyValue, userName);       }       byteCount = 0;       clearTempBuffer(tbuff);      }     }    }   } catch (IOException e) {    e.printStackTrace();   }  }

最终程序的运行结果截屏如下：