服务端高并发向客户端发送消息需要一个客户端开一个线程吗
时间: 2023-11-12 19:03:59 浏览: 31
在高并发情况下向客户端发送消息,通常需要使用异步编程模型,而不是为每个客户端开一个线程。这是因为线程开销很大,而且每个线程都需要占用操作系统资源。相反,异步编程模型使用事件驱动的方式来处理并发请求,可以更有效地利用系统资源。在异步编程模型中,可以使用回调函数、异步方法、await/async等技术来实现异步操作。
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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:
```c++
#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:
```c++
#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;
}
```
C++使用多线程实现高并发访问指定服务器和网站 客户端和服务端代码
这是一个比较复杂的问题,需要对网络编程和多线程编程有一定的了解。以下是一个简单的客户端和服务端代码示例,仅供参考。
服务端代码:
```cpp
#include <iostream>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <queue>
#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")
using namespace std;
// 服务端监听端口
const int PORT = 8080;
// 最大连接数
const int MAX_CONNECTIONS = 10;
// 互斥锁和条件变量
mutex mtx;
condition_variable cv;
// 任务队列
queue<SOCKET> tasks;
// 线程函数
void worker_thread()
{
while (true)
{
// 等待任务队列非空
unique_lock<mutex> ul(mtx);
cv.wait(ul, []() { return !tasks.empty(); });
// 取出一个任务
SOCKET client_socket = tasks.front();
tasks.pop();
// 处理任务
char buf[1024];
int n = recv(client_socket, buf, sizeof(buf), 0);
send(client_socket, buf, n, 0);
// 关闭连接
closesocket(client_socket);
}
}
int main()
{
// 初始化Winsock
WSADATA wsa;
if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
{
cerr << "WSAStartup failed" << endl;
return 1;
}
// 创建监听套接字
SOCKET listen_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (listen_socket == INVALID_SOCKET)
{
cerr << "socket failed" << endl;
return 1;
}
// 绑定地址
sockaddr_in addr = { 0 };
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = htonl(INADDR_ANY);
addr.sin_port = htons(PORT);
if (bind(listen_socket, (sockaddr*)&addr, sizeof(addr)) == SOCKET_ERROR)
{
cerr << "bind failed" << endl;
return 1;
}
// 监听端口
if (listen(listen_socket, MAX_CONNECTIONS) == SOCKET_ERROR)
{
cerr << "listen failed" << endl;
return 1;
}
// 创建工作线程
thread workers[4];
for (int i = 0; i < 4; i++)
{
workers[i] = thread(worker_thread);
}
// 接受连接并加入任务队列
while (true)
{
SOCKET client_socket = accept(listen_socket, NULL, NULL);
if (client_socket == INVALID_SOCKET)
{
cerr << "accept failed" << endl;
continue;
}
// 加入任务队列
unique_lock<mutex> ul(mtx);
tasks.push(client_socket);
cv.notify_one();
}
// 关闭监听套接字
closesocket(listen_socket);
// 关闭Winsock
WSACleanup();
return 0;
}
```
客户端代码:
```cpp
#include <iostream>
#include <thread>
#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")
using namespace std;
// 服务器地址和端口
const char* SERVER_ADDR = "127.0.0.1";
const int PORT = 8080;
// 发送和接收数据
void send_data(SOCKET s)
{
char buf[1024] = "hello";
send(s, buf, sizeof(buf), 0);
}
void recv_data(SOCKET s)
{
char buf[1024];
int n = recv(s, buf, sizeof(buf), 0);
buf[n] = '\0';
cout << buf << endl;
}
int main()
{
// 初始化Winsock
WSADATA wsa;
if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
{
cerr << "WSAStartup failed" << endl;
return 1;
}
// 创建套接字
SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s == INVALID_SOCKET)
{
cerr << "socket failed" << endl;
return 1;
}
// 连接服务器
sockaddr_in addr = { 0 };
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = inet_addr(SERVER_ADDR);
addr.sin_port = htons(PORT);
if (connect(s, (sockaddr*)&addr, sizeof(addr)) == SOCKET_ERROR)
{
cerr << "connect failed" << endl;
return 1;
}
// 发送和接收数据
send_data(s);
recv_data(s);
// 关闭套接字
closesocket(s);
// 关闭Winsock
WSACleanup();
return 0;
}
```
需要注意的是,以上代码仅仅是一个简单的示例,实际应用中还需要考虑许多因素,如线程池的大小、任务队列的容量、异常处理等等。同时,也需要适当地添加互斥锁和条件变量来保证线程安全。