前言
本文主要学习Linux内核编程,结合 2019进行跨平台编程,内容包括高并发服务器的介绍、服务器代码封装(+epoll)、服务器/客户端测试
一、高并发服务器
什么是高并发?
高并发 是一种系统运行过程中遇到的一种 “短时间内遇到大量操作请求” 的情况
【主要发生在web系统集中大量访问收到大量请求】
举个例子:12306的抢票情况;天猫双十一活动【突然下单一万张票,上万人下单购物】
该情况发生会导致系统在这段时间内执行大量操作,例如,对资源的请求,数据库的操作等
高并发的处理指标?
高并发相关常用的一些指标有:
1️响应时间( Time)
含义:系统对请求做出响应的时间
举个例子:系统处理一个HTTP请求需要200ms,这个200ms就是系统的响应时间
2️吞吐量()
含义:单位时间内处理的请求数量
3️每秒查询率QPS(Query Per )
含义 :每秒响应请求数
在互联网领域,这个指标和吞吐量区分的没有这么明显
4️并发用户数
含义:同时承载正常使用系统功能的用户数量
举个例子:例如一个即时通讯系统,同时在线量一定程度上代表了系统的并发用户数
高并发和多线程的关系和区别?
“高并发和多线程” 总是被一起提起,给人感觉两者好像相等,实则 【高并发 ≠ 多线程】
1️多线程
2️高并发
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二、搭建服务器/客户端
服务器代码(4种类的封装)
地址类【】
.h
#pragma once
#include/* See NOTES */
#include
#include
#include
#include
class CHostAddress
{
public:
CHostAddress(char* ip, unsigned short port);
~CHostAddress();
char* getIp();
void setIp(char* ip);
unsigned short getPort();
void setPort(unsigned short port);
struct sockaddr_in getAddr_in();
struct sockaddr* getAddr();
int getLength();
private:
char ip[16]; //保存ip地址
int length; //保存 sockaddr_in 结构体长度
unsigned short port; //端口号
struct sockaddr_in s_addr;
};.cpp
#include "CHostAddress.h"
CHostAddress::CHostAddress(char* ip, unsigned short port)
{
memset(this->ip, 0, sizeof(this->ip));
strcpy(this->ip, ip);
this->port = port;
this->s_addr.sin_family = AF_INET;
this->s_addr.sin_port = htons(this->port);
this->s_addr.sin_addr.s_addr = inet_addr(this->ip);
this->length = sizeof(this->s_addr);
}
CHostAddress::~CHostAddress()
{
}
char* CHostAddress::getIp()
{
return this->ip;
}
void CHostAddress::setIp(char* ip)
{
strcpy(this->ip, ip);
}
unsigned short CHostAddress::getPort()
{
return this->port;
}
void CHostAddress::setPort(unsigned short port)
{
this->port = port;
}
sockaddr_in CHostAddress::getAddr_in()
{
return this->s_addr;
}
sockaddr* CHostAddress::getAddr()
{
// bind函数需要用到struct sockaddr *,因此return类型转换之后数据
return (struct sockaddr*)&(this->s_addr);
}
int CHostAddress::getLength()
{
return this->length;
}类【】
.h
#pragma once
#include//socket头文件
#include//socket头文件
#include
#include
class CBaseSocket
{
public:
CBaseSocket(char* ip, unsigned short port);
~CBaseSocket();
void Start();
int getSocketFd();
virtual void Run() = 0;//写成纯虚函数,子类来实现
virtual void Stop() = 0;//写成纯虚函数,子类来实现
protected:
int socketFd;//写到受保护区,子类可以用到
};.cpp
#include "CBaseSocket.h"
CBaseSocket::CBaseSocket(char* ip, unsigned short port)
{
this->socketFd = 0;
}
CBaseSocket::~CBaseSocket()
{
}
void CBaseSocket::Start()
{
//打通网络通道
this->socketFd = socket(AF_INET, SOCK_STREAM, 0);//IPPROTO_TCP用0替换也行
if (this->socketFd < 0)//大于0成功,小于0失败
{
perror("socket error");//socket创建失败
}
this->Run();//子类实现的run函数
}
int CBaseSocket::getSocketFd()
{
return this->socketFd;
}TCP类【】
.h
#pragma once
#include
#include "CBaseSocket.h"
#include "CHostAddress.h"
#include
#include
#include
#include/* See NOTES */
#include
using namespace std;
#define LISTEN_MAX_NUM 10
class CTcpServer :
public CBaseSocket
{
public:
CTcpServer(char* ip, unsigned short port);
~CTcpServer();
void Run();
void Stop();
CHostAddress* getAddress();
void setAddress(CHostAddress* address);
private:
CHostAddress* address;//地址类
};.cpp
#include "CTcpSever.h"
CTcpServer::CTcpServer(char* ip, unsigned short port)
:CBaseSocket(ip, port)
{
this->address = new CHostAddress(ip, port);
}
CTcpServer::~CTcpServer()
{
}
void CTcpServer::Run()
{
int opt_val = 1;
int res = 0;
//端口复用 解决出现 adress already use的问题
res = setsockopt(this->socketFd, SOL_SOCKET, SO_REUSEADDR, (const void*)&opt_val, sizeof(opt_val));
if (res == -1)
{
perror("setsockopt error");
}
//绑定端口号和地址 协议族
res = bind(this->socketFd, this->address->getAddr(), this->address->getLength());
if (res == -1)
{
perror("bind error");
}
//监听这个地址和端口有没有客户端来连接
res = listen(this->socketFd, LISTEN_MAX_NUM);
if (res == -1)
{
perror("listen error");
}
cout << "Server start success socketFd = " << this->socketFd << endl;
}
void CTcpServer::Stop()
{
if (this->socketFd != 0)
{
close(this->socketFd);
this->socketFd = 0;
}
}
CHostAddress* CTcpServer::getAddress()
{
return this->address;
}
void CTcpServer::setAddress(CHostAddress* address)
{
this->address = address;
}epoll类 【】
.h
#pragma once
#include
#include
#include "CTcpSever.h"
#define EPOLL_SIZE 5
using namespace std;
class CEpollServer
{
public:
CEpollServer(char* ip, unsigned short port);
~CEpollServer();
void Start();
private:
int epollfd;
int epollwaitefd;
int acceptFd;
char buf[1024]; //存放客户端发来的消息
struct epoll_event epollEvent;
struct epoll_event epollEventArray[5];
CTcpServer* tcp;//TCP类
};.cpp
#include "CEpollServer.h"
CEpollServer::CEpollServer(char* ip, unsigned short port)
{
//初始化 TcpServer类
this->tcp = new CTcpServer(ip, port);
this->tcp->Start();
cout << "socketFd = " << this->tcp->getSocketFd() << endl;
//初始化数据成员
this->epollfd = 0;
this->epollwaitefd = 0;
this->acceptFd = 0;
bzero(this->buf, sizeof(this, buf));
//事件结构体初始化
bzero(&(this->epollEvent), sizeof(this->epollEvent));
//绑定当前准备好的sockedfd(可用网络对象)
this->epollEvent.data.fd = this->tcp->getSocketFd();
//绑定事件为客户端接入事件
this->epollEvent.events = EPOLLIN;
//创建epoll
this->epollfd = epoll_create(EPOLL_SIZE);
//将已经准备好的网络描述符添加到epoll事件队列中
epoll_ctl(this->epollfd, EPOLL_CTL_ADD, this->tcp->getSocketFd(), &(this->epollEvent));
}
CEpollServer::~CEpollServer()
{
}
void CEpollServer::Start()
{
while (1)
{
cout << "epoll wait client" << endl;
this->epollwaitefd = epoll_wait(this->epollfd, epollEventArray, EPOLL_SIZE, -1);
if (this->epollwaitefd < 0)
{
perror("epoll wait error");
}
for (int i = 0; i < this->epollwaitefd; i++)
{
//判断是否有客户端上线
if (epollEventArray[i].data.fd == this->tcp->getSocketFd())
{
cout << "网络_开始工作_等待客户端_上线" << endl;
this->acceptFd = accept(this->tcp->getSocketFd(), NULL, NULL);
cout << "acceptfd = " << this->acceptFd << endl;
//上线的客户端描述符是acceptfd 绑定事件添加到epoll
epollEvent.data.fd = this->acceptFd;
epollEvent.events = EPOLLIN; //EPOLLIN表示对应的文件描述符可以读
epoll_ctl(this->epollfd, EPOLL_CTL_ADD, this->acceptFd, &epollEvent);
}
else if (epollEventArray[i].events & EPOLLIN)
{
bzero(this->buf, sizeof(this->buf));
int res = read(epollEventArray[i].data.fd, this->buf, sizeof(this->buf));
if (res > 0)
{
cout << "服务器_收到 fd = " << epollEventArray[i].data.fd << " 送达数据: buf = " << this->buf << endl;
}
else if (res <= 0)
{
cout << "客户端 fd = " << epollEventArray[i].data.fd << " _掉线_" << endl;
close(epollEventArray[i].data.fd);
//从epoll中删除客户端描述符
epollEvent.data.fd = epollEvent.data.fd;
epollEvent.events = EPOLLIN;
epoll_ctl(this->epollfd, EPOLL_CTL_DEL, epollEventArray[i].data.fd, &epollEvent);
}
}
}
}
}客户端代码
案例测试
main.cpp
#include
#include "CEpollServer.h"
using namespace std;
int main()
{
CEpollServer* epoll = new CEpollServer("192.168.48.129", 12345);
epoll->Start();
return 0;
}测试效果
通过Linux连接VS进行跨平台编程,上为本文设计的服务器,下为两个与之相连的客户端,在客户端1和客户端2中输入内容,服务器上能接收到相应的信息,即表示测试成功!如下图所示:
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