Java TCP通信概念及实例

TCP/UDP 协议

通俗解释：

TCP协议和UDP协议的区别类似于电话系统和邮政系统。

<1>TCP：类似于电话系统，建立双向的通信通道，确定连接，话音顺序接听。

<2>UDP：类似于邮政系统，发送方将信件发送到正确的地址，但并不知道准确的邮路，大多数邮件到达了目的地，个别情况一些邮件会在路上丢失。邮件不保证顺序到达目的地。

TCP套接字

Socket

　　客户端的通信套接字，可指定远端IP地址、端口进行连接通信，也可以通过方法获取已连接的socket的远端IP地址、端口，以及将此socket以字节输入流和输出流的形式返回，当与数据输入流和输出流绑定，便可实现客户端的网络通信。

　　构造函数均为public修饰类型，如果创建socket时发生I/O错误，均抛出IOException异常。常用构造函数如下：

Socket(InetAddress address,int port):创建一个socket并与规定的IP地址的指定的端口相连接。

Socket(String host,int port):创建一个socket并与指定主机的指定端口连接。

ServerSocket

服务器的通讯套接字，用来侦听客户端请求的连接，并为每个新连接创建一个socket对象，由此创建绑定此socket的输入流和输出流，与客户端实现网络通信。

　　构造函数均为public修饰类型，如果创建socket时发生I/O错误，均抛出IOException异常。常用构造函数如下：

　　　ServerSocket(int port):在所给定的用来侦听的端口上建立一个服务器套接字。如果端口号为0，则在任意的空闲的端口上建立要给服务器套接字。外来连接请求的数量默认最大为50。

多线程聊天室实例

服务端Cilent

　　创建ServerSocket并监听设置的端口，调用accpet()方法，直到找到对应的socket与之连接，创建一个线程为止服务。

　　 Launch the Application 部分为Java Swing的窗口部分。

public class ServerCilent {

    private JFrame frmServer;

    private JTextField textField;

    private JTable table;

    private JLabel lblNewLabel;

    private JButton btnRefresh;

    private JButton btnListenstart;

    private SocketManager SocketArr=new SocketManager();

    //创建 Server端

        void getServer(int port)

        {

            try {

                ServerSocket serverSocket=new ServerSocket(port);

                System.out.println("已经开启服务端");

                while(true)

                {

                    Socket socket=serverSocket.accept();

                    new W_Thread(socket).start();

                    SocketArr.add(socket);

                    SocketArr.sendClientInfo();

                }

            } catch (Exception e) {

                // TODO: handle exception

                e.printStackTrace();

            }

        }

    class W_Thread extends Thread

    {

        Socket socket=null;

        private BufferedReader reader;

        private PrintWriter writer;

        public W_Thread(Socket socket)

        {

            this.socket=socket;

        }

        public void run()

        {

            try {

                reader=new BufferedReader(new InputStreamReader(socket.getInputStream()));

                writer=new PrintWriter(socket.getOutputStream(),true);

                String msg;

                while((msg=reader.readLine())!=null )

                {

                    System.out.println(msg);

                    SocketArr.SendtoAll(msg);

                }

            } catch (Exception e) {

                // TODO: handle exception

                e.printStackTrace();

            }

        }

    }

    /**

     * Launch the application.

     */

    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {

            public void run() {

                try {

                    ServerCilent window = new ServerCilent();

                    window.frmServer.setVisible(true);

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

        });

    }

    /**

     * Create the application.

     */

    public ServerCilent() {

        initialize();

    }

    /**

     * Initialize the contents of the frame.

     */

    private void initialize() {

        frmServer = new JFrame();

        frmServer.setResizable(false);

        frmServer.setTitle("ServerCilent");

        frmServer.setBounds(100, 100, 452, 371);

        frmServer.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frmServer.getContentPane().setLayout(null);

        JPanel panel = new JPanel();

        panel.setBorder(new TitledBorder(null, "DefaultSetting", TitledBorder.LEADING, TitledBorder.TOP, null, null));

        panel.setBounds(10, 10, 414, 66);

        frmServer.getContentPane().add(panel);

        panel.setLayout(null);

        JLabel lblPort = new JLabel("Port:");

        lblPort.setBounds(10, 25, 54, 15);

        panel.add(lblPort);

        textField = new JTextField();

        textField.setBounds(48, 22, 122, 21);

        panel.add(textField);

        textField.setColumns(10);

        btnListenstart = new JButton("Listen&Start");

        btnListenstart.addMouseListener(new MouseAdapter() {

            @Override

            public void mouseClicked(MouseEvent arg0) {

                int port=Integer.parseInt(textField.getText());

                ServerCilent serverCilent=new ServerCilent();

                serverCilent.getServer(port);

                textField.setEditable(false);

                btnListenstart.setVisible(false);

            }

        });

        btnListenstart.setBounds(254, 21, 136, 23);

        panel.add(btnListenstart);

        JLabel label = new JLabel("在线人数：");

        label.setBounds(10, 298, 82, 15);

        frmServer.getContentPane().add(label);

        lblNewLabel = new JLabel(String.valueOf(SocketArr.size()));

        lblNewLabel.setBounds(75, 298, 54, 15);

        frmServer.getContentPane().add(lblNewLabel);

        btnRefresh = new JButton("Refresh");

        btnRefresh.setBounds(331, 298, 93, 23);

        frmServer.getContentPane().add(btnRefresh);

    }

}

多线程客户端Cilent

创建Socket，并获取对应的输入输出流即可。

public class Cilent implements Runnable{

    /*Swing*/

    private JFrame frmLogincilent;

    private JTextField IPAdress;

    private JTextField Port;

    private JTextField Nickname;

    private JTextField Sendinfo;

    private JButton Sumbit;

    private JTextArea ShowArea;

    private JButton Send;

    /*Stream*/

    private BufferedReader reader;

    private PrintWriter writer;

    @Override

    public void run(){

        while(true){

            try {

                ShowArea.append(reader.readLine()+"\n");

            } catch (Exception e) {

                // TODO: handle exception

            }

        }

    }

    public void Create_Socket(InetAddress ip,int port){

        ShowArea.append("正在尝试连接到服务端…… ……"+"\n");

        try {

            Socket socket=new Socket(ip, port);

            ShowArea.append("聊天室已经准备好");

            frmLogincilent.setTitle("Ip:"+ip+"   Port:"+port+"   已连接在线");

            reader=new BufferedReader(new InputStreamReader(socket.getInputStream()));

            writer=new PrintWriter(socket.getOutputStream(),true);

            new Thread(this).start();

        } catch (Exception e) {

            // TODO: handle exception

        }

    }

    /**

     * Launch the application.

     */

    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {

            public void run() {

                try {

                    Cilent window = new Cilent();

                    window.frmLogincilent.setVisible(true);

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

        });

    }

    /**

     * Create the application.

     */

    public Cilent() {

        initialize();

    }

    /**

     * Initialize the contents of the frame.

     */

    private void initialize() {

        frmLogincilent = new JFrame();

        frmLogincilent.setResizable(false);

        frmLogincilent.setTitle("Cilent");

        frmLogincilent.setBounds(100, 100, 458, 532);

        frmLogincilent.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frmLogincilent.getContentPane().setLayout(null);

        JPanel panel = new JPanel();

        panel.setBorder(new TitledBorder(null, "Default Setting", TitledBorder.LEADING, TitledBorder.TOP, null, null));

        panel.setBounds(10, 10, 424, 84);

        frmLogincilent.getContentPane().add(panel);

        panel.setLayout(null);

        JLabel lblIpAdress = new JLabel("IP Adress:");

        lblIpAdress.setBounds(10, 20, 73, 15);

        panel.add(lblIpAdress);

        IPAdress = new JTextField();

        IPAdress.setBounds(82, 17, 142, 21);

        panel.add(IPAdress);

        IPAdress.setColumns(10);

        JLabel lblProt = new JLabel("Prot:");

        lblProt.setBounds(10, 48, 54, 15);

        panel.add(lblProt);

        Port = new JTextField();

        Port.setBounds(82, 45, 66, 21);

        panel.add(Port);

        Port.setColumns(10);

        JLabel lblNickname = new JLabel("NickName:");

        lblNickname.setBounds(170, 48, 73, 15);

        panel.add(lblNickname);

        Nickname = new JTextField();

        Nickname.setBounds(238, 45, 176, 21);

        panel.add(Nickname);

        Nickname.setColumns(10);

        Sumbit = new JButton("Lock&Login");

        Sumbit.addMouseListener(new MouseAdapter() {

            @Override

            public void mouseClicked(MouseEvent arg0) {

                    try {

                        /*Create Socket*/

                        String ipString=IPAdress.getText();

                        int port=Integer.parseInt(Port.getText());

                        String Name=Nickname.getText();

                        InetAddress ip=InetAddress.getByName(ipString);

                        Create_Socket(ip, port);

                        /*Swing*/

                        IPAdress.setEditable(false);

                        Port.setEditable(false);

                        Nickname.setEditable(false);

                        Sumbit.setVisible(false);

                    } catch (Exception e) {

                        // TODO: handle exception

                        JOptionPane.showMessageDialog(null, "invalid data");

                    }

                }

        });

        Sumbit.setBounds(272, 16, 142, 23);

        panel.add(Sumbit);

        ShowArea = new JTextArea();

        ShowArea.setBounds(10, 104, 424, 358);

        frmLogincilent.getContentPane().add(ShowArea);

        Sendinfo = new JTextField();

        Sendinfo.setBounds(10, 472, 330, 21);

        frmLogincilent.getContentPane().add(Sendinfo);

        Sendinfo.setColumns(10);

        Send = new JButton("Send");

        Send.addMouseListener(new MouseAdapter() {

            @Override

            public void mouseClicked(MouseEvent arg0) {

                writer.println(Nickname.getText()+":"+Sendinfo.getText());

                Sendinfo.setText("");

            }

        });

        Send.setBounds(349, 471, 85, 23);

        frmLogincilent.getContentPane().add(Send);

    }

}

Socket管理类

继承ArrayList，并添加发送的方法SendtoAll(),以及显示当前连接数目的方法SendCilentInfo()

public class SocketManager extends ArrayList{

    synchronized void add(Socket x)

    {

        super.add(x);

    }

    synchronized void remove(Socket x)

    {

        super.remove(x);

    }

    synchronized void SendtoAll(String str)

    {

        PrintWriter writer=null;

        Socket socket;

        for(int i=0;i<size();i++)

        {

            socket=(Socket)get(i);

            try {

                writer=new PrintWriter(socket.getOutputStream(),true);

                if(writer!=null)

                {

                    writer.println(str);

                }

            } catch (Exception e) {

                // TODO: handle exception

                e.printStackTrace();

            }

        }

    }

    synchronized void sendClientInfo()

    {

        String info="当前位于聊天室的人数为"+size();

        System.out.println(info);

        SendtoAll(info);

    }

}

示例效果：

巴特西