Java中使用UDP协议的Socket通信

叁歲伎倆 2023-03-02 13:28 2阅读 0赞

**Java中使用UDP协议的Socket通信：**

基本测试代码：  
客户端：

package udpsocket;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.InetAddress;
    
    public class Demo1_Send { 
        public static void main(String[] args) throws Exception { 
    
            // 在发生数据之前，你得先把数据准备好，发生目标的IP地址，端口
    
            // 准备一个字符串数据，待发送
            String sendMsg = "你在做什么呢？";
    
            // 获取目标主机的IP地址
            InetAddress hostIP = InetAddress.getByName("127.0.0.1");
            // 获取目标主机的端口号
            int hostPort = 6666;
    
            // 创建DatagramSocket对象，相当于创建码头
            DatagramSocket socket = new DatagramSocket();
    
            // 创建DatagramPacket对象，相当于创建船只，参数为：发数据的字节码，字节码的长度，目标IP地址，目标端口号
            DatagramPacket packet = new DatagramPacket(sendMsg.getBytes(), sendMsg.getBytes().length, hostIP, hostPort);
    
            // 开始发送数据，在码头护送包装数据的船只
            socket.send(packet);
    
            // 发送完毕后将socket关闭，码头关门
            socket.close();
        }
    }

服务器端：

package udpsocket;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    
    public class Demo1_Receive { 
        public static void main(String[] args) throws Exception { 
    
            // 创建DatagramSocket对象，并指定端口号
            DatagramSocket socket = new DatagramSocket(6666);
    
            // 创建DatagramPacket对象，并指定接收容器，及其长度
            DatagramPacket packet = new DatagramPacket(new byte[1024], 1024);
    
            // 开始接收数据
            socket.receive(packet);
    
            // 取出数据
            byte[] msgArr = packet.getData();
            // 获取有效数据的长度
            int length = packet.getLength();
    
            // 将字节码还原成字符串
            String msgStr = new String(msgArr, 0, length);
            System.out.println(msgStr);
        }
    }

--------------------

改进后的代码：

客户端：

package udpsocket;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.InetAddress;
    import java.util.Scanner;
    
    public class Demo2_Send { 
        public static void main(String[] args) throws Exception { 
    
            Scanner sc = new Scanner(System.in);
    
            DatagramSocket socket = new DatagramSocket();
    
            InetAddress hostIP = InetAddress.getByName("127.0.0.1");
            int hostPort = 7777;
    
            System.out.println("请输入发送信息，输入over结束：");
            while (sc.hasNext()) { 
                String msgStr = sc.nextLine();
                if ("over".equals(msgStr))  break;
    
                DatagramPacket packet = new DatagramPacket(msgStr.getBytes(), msgStr.getBytes().length, hostIP, hostPort);
                socket.send(packet);
            }
    
            socket.close();
        }
    }

服务器端：

package udpsocket;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    
    public class Demo2_Receive { 
        public static void main(String[] args) throws Exception { 
    
            DatagramSocket socket = new DatagramSocket(7777);
    
            while (true) { 
                DatagramPacket packet = new DatagramPacket(new byte[1024], 1024);
                socket.receive(packet);
    
                // 取出数据
                byte[] msgArr = packet.getData();
                int length = packet.getLength();
                String msgStr = new String(msgArr, 0, length);
    
                // 获取发送者的IP地址，端口号
                String srcIP = packet.getAddress().getHostAddress();
                int srcPort = packet.getPort();
    
                System.out.println(srcIP + "-" + srcPort + "：" + msgStr);
            }
        }
    }

--------------------