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() {@Overridepublic 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;@Overridepublic 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() {@Overridepublic 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 exceptionJOptionPane.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() {@Overridepublic 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：

转载于:https://www.cnblogs.com/rekent/p/6920440.html