一、頭文件【存為：connPool.h】

#ifndef __CONNECTION_POOL_H__

#define __CONNECTION_POOL_H__

#include "mutex.h"

#define?MYSQL_CONN_NUM_MAX_VALUE?500

using namespace std;

enum _USE_STATUS

{

US_USE = 0,

US_IDLE = 1

};

typedef?struct _sConStatus

{

void*?connAddr;

int?useStatus;

}sConStatus;

class CConnPool

{

public:

CConnPool();

~CConnPool();

public:

int Init(string& strMysqlIp, string&?strUser, string&?strPwd, string&?strDbName, int nMysqlPort, int nConnNum);//connection?pool init

void* getOneConn();//get a connection

void?retOneConn(void* pMysql);// return a connection

void?checkConn(); // check the connection if is alive

void* createOneConn();

public:

char m_szMysqlIp[100];

char m_szUser[100];

char m_szPwd[100];

char m_szDbName[100];

int?m_nMysqlPort;?int?m_nConnNum;

public:

CMutex?m_sMutex;

vector?m_vectorConn;

map m_mapVI;

map m_mapMysqlScs;

};

class CConnPoolV2

{

public:

CConnPoolV2();

~CConnPoolV2();

public:

int Init(string& strMysqlIp, string&?strUser, string&?strPwd, string&?strDbName, int nMysqlPort, int nConnNum);//connection?pool init

void* getOneConn(); //從連接池取一個連接

void?retOneConn(void* pConn);// 連接用完了，把它放回連接池。以便其他人用。

void?checkConn(); // check the connection if is alive

void* createOneConn();

private:

string m_strMysqlIp;

string m_strUser;

string m_strPwd;

string m_strDbName;

int?m_nMysqlPort;?int?m_nConnNum;

private:

CMutex?m_sMutex;

vector?m_vectorConn;

map m_mapVI; //?從連接的地址，快速找到索引，便于存放到m_vectorConn中。

};

#endif

二、源碼【存為：connPool.cpp】

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include ?#include ?#include

#include

#include

#include

#include "mysql.h"

#include "encapsulation_mysql.h"

#include "connPool.h"

#include "mutex.h"

using namespace std;

using namespace EncapMysql;

CConnPool::CConnPool( )

{

}

CConnPool::~CConnPool( )

{

}

void* CConnPool::createOneConn()

{

MYSQL*?mysql;

mysql = mysql_init(0);

if(mysql == NULL)

{

cout << "mysql_init fail**" << endl;?return NULL;

}

if(mysql_real_connect(mysql,?m_szMysqlIp , m_szUser ,?m_szPwd,?m_szDbName?,?m_nMysqlPort, NULL,0)==NULL)

{

cout << "connect failure!" << endl;

return NULL;

}

else

{

cout << "connect success!" << endl;

}

//

return mysql;

}

int CConnPool::Init(string& strMysqlIp, string&?strUser, string&?strPwd, string&?strDbName, int nMysqlPort, int nConnNum)

{

strcpy(m_szMysqlIp, strMysqlIp.c_str());

strcpy( m_szUser, strUser.c_str());

strcpy(m_szPwd, strPwd.c_str());

strcpy(m_szDbName, strDbName.c_str());

m_nMysqlPort = nMysqlPort;?m_nConnNum = nConnNum;?MYSQL*?mysql;

for(int i=0; i

{

mysql = (MYSQL*)this->createOneConn();

if(mysql == NULL)

return -1;

//?sConStatus* scs = new sConStatus();

scs->connAddr = mysql;

scs->useStatus = US_IDLE;

m_vectorConn.push_back(scs);?m_mapVI[scs] = i;

m_mapMysqlScs[mysql] = scs;

}

m_nConnNum = nConnNum;

}

//從連接池中取一個連接，同時，給它做一個標記，表明它已經被使用，防止別的線程再使用。

void* CConnPool::getOneConn()

{

int N = m_vectorConn.size();

for(int i=0; i< N; i++)

{

CGuard?guard(m_sMutex);

sConStatus* scs = (sConStatus*)m_vectorConn[i];

if(scs->useStatus ==?US_IDLE)

{

scs->useStatus = US_USE;

return?scs->connAddr;

}?}

//

return NULL;

}

//把連接歸還給連接池。同時，給它做一個標記，表明它是空閑的，可以使用。

void?CConnPool::retOneConn(void* pMysql)

{

if(!pMysql)

return;

//?map::iterator?it1;

map::iterator it2;

CGuard?guard(m_sMutex);

it1 = m_mapMysqlScs.find(pMysql);

if(it1 == m_mapMysqlScs.end())

return;

it2 = m_mapVI.find(it1->second);

if(it2 == m_mapVI.end())

return;

int nInx = it2->second;

sConStatus* scs = (sConStatus*) m_vectorConn[nInx];

scs->useStatus = US_IDLE;

}

void?CConnPool::checkConn()

{

map::iterator?it1;

MYSQL*?mysql;

//?for(int i=0; i

{

CGuard?guard(m_sMutex);

sConStatus* scs = (sConStatus*)m_vectorConn[i];

if(scs->useStatus == US_USE)

continue;

//?mysql =(MYSQL*)(scs->connAddr);

int status=mysql_query(mysql, "select count(*) from t_user;" );

if(status != 0) //說明連接已經不可用了。

{

it1 = m_mapMysqlScs.find(mysql);

if(it1 != m_mapMysqlScs.end())

{

m_mapMysqlScs.erase(it1);

}

//

mysql_close(mysql);

//

mysql = (MYSQL*)this->createOneConn();

m_mapMysqlScs[mysql] = scs;

}

}

//

}

// 2011-01-20, 這個類這樣寫，感覺耦合性更為松散，比較好。使用起來也好理解一些。

CConnPoolV2::CConnPoolV2( )

{

}

CConnPoolV2::~CConnPoolV2( )

{

}

//創建一個連接，并設為 IDLE狀態。

void* CConnPoolV2::createOneConn()

{

try

{

CEncapMysql*?pEM = new CEncapMysql();

if(pEM == NULL)

{

printf("pEM == NULL**\r\n");?return NULL;

}?//

int nRet = pEM->Connect(m_strMysqlIp.c_str(), m_strUser.c_str(), m_strPwd.c_str());

if(nRet != 0)

{

printf("pEM->Connect fail**\r\n");?return NULL;

}?//?pEM->SetIdle();

//

return pEM;

}?catch(...)

{

printf("createOneConn?exception**\r\n");?return NULL;

}

}

//成功： 返回0

int CConnPoolV2::Init(string& strMysqlIp, string&?strUser, string&?strPwd, string&?strDbName, int nMysqlPort, int nConnNum)

{

m_strMysqlIp?= strMysqlIp;

m_strUser?= strUser;

m_strPwd?= strPwd;

m_strDbName?= strDbName;

m_nMysqlPort = nMysqlPort;?m_nConnNum = nConnNum;?CEncapMysql* pEM;

int nRet;

for(int i=0; i

{

pEM = (CEncapMysql*)this->createOneConn();

if(!pEM )

return -1;

//?m_vectorConn.push_back(pEM);?m_mapVI[pEM] = i;

}

return?0;

}

void* CConnPoolV2::getOneConn()

{

CGuard?guard(m_sMutex);

//

for(int i=0; i< m_nConnNum; i++)

{

CEncapMysql* pEM = (CEncapMysql*)m_vectorConn[i];

if( pEM->IsIdle())

{

pEM->SetUsed();

return pEM;

}?}

//可能訪問MYSQL的用戶較多，連接池中已無空閑連接了。只要總連接數沒有超限，就新建一個連接。

if(m_nConnNum < MYSQL_CONN_NUM_MAX_VALUE)

{

CEncapMysql* pEM = (CEncapMysql*)this->createOneConn();

if(!pEM )

return NULL;

//?m_vectorConn.push_back(pEM);?m_mapVI[pEM] = m_nConnNum++;

}?//

return NULL;

}

void?CConnPoolV2::retOneConn(void* pConn)

{

map::iterator it;

CGuard?guard(m_sMutex);

it = m_mapVI.find(pConn);

if(it == m_mapVI.end())

{

printf("retOneConn?fail***\n");?return;

}?int nInx = it->second;

CEncapMysql* pEM = (CEncapMysql*) m_vectorConn[nInx];

pEM->SetIdle();

printf("retOneConn?succ!\n");?}

void?CConnPoolV2::checkConn()

{

//暫時可以不實現。因為查詢失敗時，已重新連接了。

}

總結

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