C++实现多并发访问指定网站或者服务器 客户端和服务端 代码

以下是一个基本的客户端和服务端实现，利用多线程实现多并发访问指定网站或者服务器：

客户端代码：

#include <iostream>
#include <thread>
#include <vector>
#include <chrono>
#include <string>
#include <cstring>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>

void send_request(int n, std::string server_ip, int server_port) {
    // 创建socket
    int sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        std::cout << "Error: Failed to create socket." << std::endl;
        return;
    }

    // 连接服务器
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(server_port);
    server_addr.sin_addr.s_addr = inet_addr(server_ip.c_str());

    if (connect(sock, (struct sockaddr*)&server_addr, sizeof(server_addr)) < 0) {
        std::cout << "Error: Failed to connect to server." << std::endl;
        close(sock);
        return;
    }

    // 发送请求
    std::string message = "Hello server " + std::to_string(n);
    send(sock, message.c_str(), message.size(), 0);

    // 接收响应
    char buffer[1024] = {0};
    int valread = read(sock, buffer, 1024);
    std::cout << "Server response for client " << n << ": " << buffer << std::endl;

    // 关闭socket
    close(sock);
}

int main(int argc, char* argv[]) {
    if (argc != 4) {
        std::cout << "Usage: ./client [server_ip] [server_port] [num_clients]" << std::endl;
        return 0;
    }

    std::string server_ip = argv[1];
    int server_port = std::stoi(argv[2]);
    int num_clients = std::stoi(argv[3]);

    std::vector<std::thread> threads;
    for (int i = 0; i < num_clients; ++i) {
        threads.emplace_back(send_request, i, server_ip, server_port);
    }

    for (auto& thread : threads) {
        thread.join();
    }

    return 0;
}

服务端代码：

#include <iostream>
#include <thread>
#include <chrono>
#include <cstring>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>

void handle_connection(int sock) {
    // 接收请求
    char buffer[1024] = {0};
    int valread = read(sock, buffer, 1024);
    std::cout << "Received: " << buffer << std::endl;

    // 发送响应
    std::string message = "Server response: " + std::string(buffer);
    send(sock, message.c_str(), message.size(), 0);

    // 关闭socket
    close(sock);
}

int main(int argc, char* argv[]) {
    if (argc != 2) {
        std::cout << "Usage: ./server [port]" << std::endl;
        return 0;
    }

    int port = std::stoi(argv[1]);

    // 创建socket
    int server_sock = socket(AF_INET, SOCK_STREAM, 0);
    if (server_sock < 0) {
        std::cout << "Error: Failed to create socket." << std::endl;
        return 0;
    }

    // 绑定socket
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(port);
    server_addr.sin_addr.s_addr = INADDR_ANY;
    if (bind(server_sock, (struct sockaddr*)&server_addr, sizeof(server_addr)) < 0) {
        std::cout << "Error: Failed to bind socket." << std::endl;
        close(server_sock);
        return 0;
    }

    // 监听socket
    if (listen(server_sock, 5) < 0) {
        std::cout << "Error: Failed to listen on socket." << std::endl;
        close(server_sock);
        return 0;
    }

    // 处理连接
    while (true) {
        int sock = accept(server_sock, NULL, NULL);
        if (sock < 0) {
            std::cout << "Error: Failed to accept connection." << std::endl;
            continue;
        }

        std::thread(handle_connection, sock).detach();
    }

    return 0;
}

在使用时，可以在终端中分别运行客户端和服务端程序：

# 启动服务端
$ ./server 8888

# 启动多个客户端
$ ./client 127.0.0.1 8888 10

其中，`./server 8888` 表示启动服务端程序，监听本地 8888 端口；`./client 127.0.0.1 8888 10` 表示启动 10 个客户端程序，分别连接到本地 8888 端口。