以下是最基础的UDP服务端与客户端源代码，实现客户端发送数据，服务器接收数据的功能。与TCP的区别在于客户端与服务端无需经过三次握手建立连接，可直接在相应端口收发数据。且内部没有流控，重发等机制进行可靠性保证，协议实现相对TCP简单。可简单认为是带有端口信息的IP数据报。

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一、C++实现

【1】服务端源代码（Windows）

#include "stdafx.h"
#include<WinSock2.h>
#include<iostream>
using namespace std;
#pragma comment(lib,"ws2_32.lib")int _tmain(int argc, _TCHAR* argv[])
{//初始化socket资源 WSADATA WSAData;WORD sockVersion=MAKEWORD(2,2);if(WSAStartup(sockVersion,&WSAData)!=0)return 0;SOCKET serSocket = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);	//创建服务器socketif(INVALID_SOCKET==serSocket){cout<<"socket error!";return 0;}//设置传输协议、端口以及目的地址 sockaddr_in serAddr;serAddr.sin_family=AF_INET;serAddr.sin_port=htons(8888);serAddr.sin_addr.S_un.S_addr=INADDR_ANY;if(bind(serSocket,(sockaddr*)&serAddr,sizeof(serAddr))==SOCKET_ERROR)	 //将socket绑定地址 {cout<<"bind error";closesocket(serSocket);return 0;}sockaddr_in clientAddr;int iAddrlen=sizeof(clientAddr);char buff[1024];	//建立接收缓存字节数组 while(true){memset(buff,0,1024);	//清空接收缓存数组//开始接收数据 int len=recvfrom(serSocket,buff,1024,0,(sockaddr*)&clientAddr,&iAddrlen);if(len>0){cout<<"客户端地址："<<inet_ntoa(clientAddr.sin_addr)<<endl;cout<<buff;//	sendto(serSocket,buff,1024,0,(sockaddr*)&clientAddr,iAddrlen);}}closesocket(serSocket);		//关闭socket WSACleanup();return 0;
}

【2】客户端源代码

#include "stdafx.h"
#include<WinSock2.h>
#include<iostream>
using namespace std;
#pragma comment(lib,"ws2_32.lib")int _tmain(int argc, _TCHAR* argv[])
{WSADATA WSAData;WORD sockVersion=MAKEWORD(2,2);if(WSAStartup(sockVersion,&WSAData)!=0)return 0;SOCKET clientSocket = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);if(INVALID_SOCKET==clientSocket){cout<<"socket error!";return 0;}sockaddr_in dstAddr;dstAddr.sin_family=AF_INET;dstAddr.sin_port=htons(8888);dstAddr.sin_addr.S_un.S_addr=inet_addr("127.0.0.1");const char* sendData="来自客户端的数据包。";sendto(clientSocket,sendData,strlen(sendData),0,(sockaddr*)&dstAddr,sizeof(dstAddr));closesocket(clientSocket);WSACleanup();return 0;
}

运行结果：

二、Rust实现

【1】服务端代码：

use std::net::UdpSocket;fn main() {let socket = UdpSocket::bind("0.0.0.0:8888").unwrap();let mut buf = [0; 65535];loop {let (amt, src) = socket.recv_from(&mut buf).unwrap();println!("received {} bytes from: {:?}", amt, src);}
}

【2】客户端代码：

use std::net::UdpSocket;
use std::thread;
fn main() {let socket = UdpSocket::bind("0.0.0.0:22222").unwrap();let buf = [1u8; 60000];let mut count = 1;loop {socket.send_to(&buf[0..count], "192.168.2.237:8888").unwrap();count = count + 1;if count == 2 {break;}}thread::sleep_ms(1000);
}