场景：Linux上C++访问MySQL连接池
Linux下C++访问MySQL连接池
实现是基于mysql connector C++ api的
connpool.h文件
/**
*数据库连接池(单例模式)
**/
#ifndef CONN_POOL_H
#define CONN_POOL_H
#include
#include
#include
#include
#include
#include
#include
#include “push.h”
#include “mutex.h”
using namespace std;
class ConnPool{
private:
deque<:connection> conns;//连接队列
int curSize;//当前队列中路连接数目
int maxSize;//最大连接数目
sql::ConnectOptionsMap connectionProperties;
Mutex *lock;//连接队列互斥锁
static ConnPool * connPool;
sql::Driver * driver;//mysql connector C++ driver
sql::Connection * CreateConnection();//创建一个连接
void TerminateConnection(sql::Connection * conn);//终止一个连接
void Init(int initialSize);//初始化连接池
void Destroy();//销毁连接池
protected:
ConnPool(string host,string user,string password,int maxSize);
public:
~ConnPool();
sql::Connection * GetConnection();//获取一个连接
void ReleaseConnection(sql::Connection * conn);//释放一个连接
sql::Connection * GetConnectionTry(int maxNum);//GetConnection的加强版，maxNum代表重试次数
static ConnPool * GetInstance();//获取一个ConnPool对象实例
};
#endif
connpool.cpp文件
/**
*数据库连接池
* **/
#include
#include “connpool.h”
#include “config.h”
using namespace std;
extern Config *config;
ConnPool * ConnPool::connPool = NULL;
ConnPool::ConnPool(string host,string user,string password,int maxSize){
connectionProperties[“hostName”] = host;
connectionProperties[“userName”] = user;
connectionProperties[“password”] = password;
connectionProperties[“OPT_CONNECT_TIMEOUT”] = 600;
connectionProperties[“OPT_RECONNECT”] = true;
this->maxSize = maxSize;
this->lock = new Mutex();
this->curSize = 0;
//初始化driver
try{
this->driver = sql::mysql::get_driver_instance(); //这里不是线程安全的
}
catch(sql::SQLException &e){
string errorMsg = string(“SQLException: “) + e.what() + string(” MySQL error code: “) + int_to_string(e.getErrorCode()) + string(” SQLState “) + e.getSQLState();
Log::Write(__FILE__,__FUNCTION__,__LINE__,errorMsg);
}
catch(std::runtime_error &e){
string errorMsg = string(“runtime_error: “) + e.what();
Log::Write(__FILE__,__FUNCTION__,__LINE__,errorMsg);
}
//初始化连接池
this->Init(maxSize/2);
}
ConnPool::~ConnPool(){
this->Destroy();
delete lock;
}
ConnPool *ConnPool::GetInstance(){
if(connPool == NULL) {
connPool = new ConnPool(config->GetVar(“db_host”),config->GetVar(“db_user”),config->GetVar(“db_password”),string_to_int(config->GetVar(“max_db_conn_size”)));
}
return connPool;
}
void ConnPool::Init(int size){
sql::Connection * conn ;
lock->Lock();
for(int i = 0; i < size ;){
conn = this->CreateConnection();
if(conn){
i++;
conns.push_back(conn);
++curSize;
}
else{
Log::Write(__FILE__,__FUNCTION__,__LINE__,”Init connpooo fail one”);
}
}
lock->UnLock();
}
void ConnPool::Destroy(){
deque<:connection>::iterator pos;
lock->Lock();
for(pos = conns.begin(); pos != conns.end();++pos){
this->TerminateConnection(*pos);
}
curSize = 0;
conns.clear();
lock->UnLock();
}
sql::Connection * ConnPool::CreateConnection(){//这里不负责curSize的增加
sql::Connection *conn;
try{
conn = driver->connect(connectionProperties);
Log::Write(__FILE__,__FUNCTION__,__LINE__,”create a mysql conn”);
return conn;
}
catch(sql::SQLException &e){
string errorMsg = string(“SQLException:”) + e.what() + string(” MySQL error code: “) + int_to_string(e.getErrorCode()) + string(” SQLState “) + e.getSQLState();
Log::Write(__FILE__,__FUNCTION__,__LINE__,errorMsg);
return NULL;
}
catch(std::runtime_error &e){
string errorMsg = string(“runtime_error: “) + e.what();
Log::Write(__FILE__,__FUNCTION__,__LINE__,errorMsg);
return NULL;
}
}
void ConnPool::TerminateConnection(sql::Connection * conn){
if(conn){
try{
conn->close();
}
catch(sql::SQLException &e){
string errorMsg = string(“SQLException:”) + e.what() + string(” MySQL error code: “) + int_to_string(e.getErrorCode()) + string(” SQLState “) + e.getSQLState();
Log::Write(__FILE__,__FUNCTION__,__LINE__,errorMsg);
}
catch(std::runtime_error &e){
string errorMsg = string(“runtime_error: “) + e.what();
Log::Write(__FILE__,__FUNCTION__,__LINE__,errorMsg);
}
delete conn;
}
}
sql::Connection * ConnPool::GetConnection(){
sql::Connection * conn;
lock->Lock();
if(conns.size() > 0){//有空闲连接,则返回
conn = conns.front();
conns.pop_front();
if(conn->isClosed()){ //如果连接关闭,则重新打开一个连接
Log::Write(__FILE__,__FUNCTION__,__LINE__,”a mysql conn has been closed”);
delete conn;
conn = this->CreateConnection();
}
if(conn == NULL){ //创建连接不成功
–curSize;
}
lock->UnLock();
return conn;
}
else{
if(curSize < maxSize){//还可以创建新的连接
conn = this->CreateConnection();
if(conn){
++curSize;
lock->UnLock();
return conn;
}
else{
lock->UnLock();
return NULL;
}
}
else{//连接池已经满了
lock->UnLock();
return NULL;
}
}
}
void ConnPool::ReleaseConnection(sql::Connection * conn){
if(conn){
lock->Lock();
conns.push_back(conn);
lock->UnLock();
}
}
sql::Connection * ConnPool::GetConnectionTry(int maxNum){
sql::Connection * conn;
for(int i = 0; i < maxNum; ++i){
conn = this->GetConnection();
if(conn){
return conn;
}
else {
sleep(2);
}
}
return NULL;
}
1 楼
wxqhbw2008
2012-10-26
我刚学c++，这个connpool.h文件copy过去就报错，报以下这些头文件无法打开，这些头文件是怎么回事呀，不太懂
#include
#include
#include
#include
#include
#include
#include
#include “push.h”
#include “mutex.h”
谢谢提点