java成神之——网络编程基本操作

• 网络编程
  • 获取ip
  • UDP程序示例
  • TCP程序
• 结语

网络编程

获取ip

InetAddress id = InetAddress.getLocalHost();                    // InetAddress id = InetAddress.getByName("www.baidu.com");

System.out.println(id);                                         // DESKTOP-S2V8PJF/192.168.0.35
System.out.println(id.getHostName());                           // DESKTOP-S2V8PJF
System.out.println(id.getHostAddress());                        // 192.168.0.35

UDP程序示例

发送端
    public class Send {
        public static void main(String[] args) {
            try {
                byte[] sendData = "发送的数据".getBytes();
                InetAddress id = InetAddress.getByName("127.0.0.1");
                DatagramPacket dp = new DatagramPacket(sendData, sendData.length, id, 9000);
                DatagramSocket ds = null;
                try {
                    ds = new DatagramSocket();
                    try {
                        ds.send(dp);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                } catch (SocketException e) {
                    e.printStackTrace();
                } finally {
                    ds.close();
                }
            } catch (UnknownHostException e) {
                e.printStackTrace();
            }
        }
    }

接收端
    public class Receive  {
        public static void main(String[] args) {
            DatagramSocket ds = null;
            DatagramPacket dp = null;
            byte[] receiveData = new byte[1024];
            try {
                ds = new DatagramSocket(9000);
                dp = new DatagramPacket(receiveData, receiveData.length);
                try {
                    ds.receive(dp);
                    System.out.println("由" + dp.getAddress().getHostAddress()+ ":" + dp.getPort() + "发送的数据->" + new String(receiveData, 0, dp.getLength()));
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } catch (SocketException e) {
                e.printStackTrace();
            }finally {
                ds.close();
            }
        }
    }

TCP程序

客户端
    public class ClientSide {
        public static void main(String[] args) {
            Socket so;
            OutputStream os;
            try {
                so = new Socket("127.0.0.1", 9000);
                os = so.getOutputStream();
                os.write("我是 客户端".getBytes()); // 给服务器发送数据

                InputStream in = so.getInputStream();
                byte[] data = new byte[1024];
                int len = in.read(data);
                System.out.println(new String(data, 0, len)); // 接受服务器数据

                so.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

服务端
    public class ServerSide  {
        public static void main(String[] args) {
            ServerSocket ss;
            Socket so;
            OutputStream os;
            try {
                ss = new ServerSocket(9000);
                so = ss.accept();
                InputStream in = so.getInputStream();
                byte[] data = new byte[1024];
                int len = in.read(data);
                System.out.println(new String(data, 0, len));  // 接受客户端数据

                os = so.getOutputStream();
                os.write("知道了".getBytes());  // 发送数据给客户端

                os.close();
                so.close();
                ss.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

结语

本文章是java成神的系列文章之一

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