C++利用多线程技术实现高并发访问 客户端和服务端代码

以下是一个简单的基于C++11标准的多线程TCP服务端和客户端代码示例：

服务端代码：

#include <iostream>
#include <thread>
#include <mutex>
#include <vector>
#include <cstring>
#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>

const int MAX_CONNECTIONS = 10; // 最大连接数

std::mutex g_mutex; // 互斥量
std::vector<int> g_connections; // 客户端连接列表

void client_handler(int client_socket) {
    char buffer[1024];

    while (true) {
        memset(buffer, 0, sizeof(buffer));
        int bytes_received = recv(client_socket, buffer, sizeof(buffer), 0);

        if (bytes_received <= 0) {
            // 客户端断开连接
            break;
        }

        // 处理客户端请求
        // ...

        // 发送响应
        send(client_socket, buffer, bytes_received, 0);
    }

    // 关闭客户端连接
    close(client_socket);

    // 删除客户端连接
    std::lock_guard<std::mutex> lock(g_mutex);
    auto it = std::find(g_connections.begin(), g_connections.end(), client_socket);
    if (it != g_connections.end()) {
        g_connections.erase(it);
    }
}

int main() {
    int server_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (server_socket == -1) {
        std::cerr << "Failed to create server socket" << std::endl;
        return 1;
    }

    // 绑定监听地址和端口
    sockaddr_in server_address;
    memset(&server_address, 0, sizeof(server_address));
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = INADDR_ANY;
    server_address.sin_port = htons(12345);
    if (bind(server_socket, (sockaddr*)&server_address, sizeof(server_address)) == -1) {
        std::cerr << "Failed to bind server socket" << std::endl;
        return 1;
    }

    // 开始监听
    if (listen(server_socket, MAX_CONNECTIONS) == -1) {
        std::cerr << "Failed to listen on server socket" << std::endl;
        return 1;
    }

    std::cout << "Server started" << std::endl;

    while (true) {
        // 等待客户端连接
        sockaddr_in client_address;
        socklen_t client_address_size = sizeof(client_address);
        int client_socket = accept(server_socket, (sockaddr*)&client_address, &client_address_size);

        if (client_socket == -1) {
            std::cerr << "Failed to accept client connection" << std::endl;
            continue;
        }

        // 添加客户端连接
        std::lock_guard<std::mutex> lock(g_mutex);
        if (g_connections.size() >= MAX_CONNECTIONS) {
            std::cerr << "Max connections reached" << std::endl;
            close(client_socket);
            continue;
        }
        g_connections.push_back(client_socket);

        // 处理客户端请求
        std::thread t(client_handler, client_socket);
        t.detach();
    }

    // 关闭服务器
    close(server_socket);
    return 0;
}

客户端代码：

#include <iostream>
#include <cstring>
#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>

int main() {
    int client_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (client_socket == -1) {
        std::cerr << "Failed to create client socket" << std::endl;
        return 1;
    }

    // 连接服务器
    sockaddr_in server_address;
    memset(&server_address, 0, sizeof(server_address));
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = inet_addr("127.0.0.1");
    server_address.sin_port = htons(12345);
    if (connect(client_socket, (sockaddr*)&server_address, sizeof(server_address)) == -1) {
        std::cerr << "Failed to connect to server" << std::endl;
        return 1;
    }

    std::cout << "Connected to server" << std::endl;

    char buffer[1024];
    while (true) {
        // 发送请求
        std::string request;
        std::cout << "Enter request: ";
        std::getline(std::cin, request);
        if (request.empty()) {
            break;
        }
        send(client_socket, request.c_str(), request.length(), 0);

        // 接收响应
        memset(buffer, 0, sizeof(buffer));
        int bytes_received = recv(client_socket, buffer, sizeof(buffer), 0);
        if (bytes_received <= 0) {
            break;
        }

        // 处理响应
        std::cout << "Response: " << buffer << std::endl;
    }

    // 关闭客户端
    close(client_socket);
    return 0;
}