Code sea supplements: MySQL-based connector/c++ MySQL operation (connection pooling)

1. mysql Installation and simple setup

(1) Installation: Under the OSX system, you can use the universal "Brew Install" command to install: Brew isntall mysql (default to install the latest version of MySQL)

(2) Start: Brew services start MySQL

(3) Change Password: Update user Set authentication_string = password (' password '), password_expired = ' N ', password_last_changed = Now () WH ere user = ' root ';

- flush privileges; (Let the modified password take effect)

(4) Allow remote access: Update mysql.user set host = '% ' where user = ' root ';

2. MySQL connector/c++ Installation

(1) Download: MySQL connector/c++ source can be downloaded from here

(2) Installation: After decompression, the "include" directory files are copied to the "/usr/local/include" directory, "Lib" Directory files are copied into the "/usr/local/lib" directory can be

3. Sample code (lazy model based on singleton mode)

CConnPool.h

/* * CConnPool.h * * Created On:mar, 2018 * author:root * * #ifndef src_cconnpool_h_#define SRC_CCONNPOOL_H_#INCL Ude <list> #include <string> #include <pthread.h> #include <mysql_connection.h> #include < mysql_driver.h> #include <cppconn/exception.h> #include <cppconn/driver.h> #include <cppconn/ connection.h> #include <cppconn/resultset.h> #include <cppconn/prepared_statement.h> #include < Cppconn/statement.h>using namespace sql;using namespace Std;class cconnpool {public:~cconnpool (); void Initconnpool (string URL, string user, string password, int maxSize); connection* getconnection (), void Releaseconnection (connection* conn), Static Cconnpool *getinstance ();p rivate: Cconnpool (); Connection*createconnection (); Create a connection void initconnection (int iinitialsize); Initialize database connection pool void Destoryconnection (Connection *conn); Destroy database Connection object void Destoryconnpool (); Destroys database connection pool cconnpool (string url, string user, string password, int maxSize); Construction Method PrivaTe:int cursize; The number of database connections currently established int maxSize; The maximum number of database connections defined in the connection pool string user;string password;string url;list<connection*> connlist; The container queue of the connection pool STL list bidirectional linked list pthread_mutex_t lock; Thread lock static Cconnpool *connpool;driver*driver;}; #endif/* Src_cconnpool_h_ */

CConnPool.cpp

/* * CConnPool.cpp * * Created On:mar, 2018 * author:root * * #include <stdexcept> #include <exception&gt ; #include <cstdio> #include "CConnPool.h" cconnpool *cconnpool::connpool = null;//cconnpool* Cconnpool::connpool = new Cconnpool (); Cconnpool::cconnpool () {//TODO auto-generated constructor stub}void cconnpool::initconnpool (string url, string user, string password, int maxSize) {this->maxsize = Maxsize;this->cursize = 0;this->user = User;this->password = PA Ssword;this->url = Url;try{this->driver = Sql::mysql::get_driver_instance ();} catch (Sql::sqlexception &e) {perror ("drive connection error; \ n");} catch (Std::runtime_error &e) {perror ("Run error \ n");} This->initconnection (MAXSIZE/2);p thread_mutex_init (&lock, NULL);} Cconnpool::cconnpool (string url, string user, string password, int maxSize) {this->maxsize = Maxsize;this->cursize = 0;this->user = User;this->password = Password;this->url = Url;try{this->driver = Sql::mysql::get_driver_ InsTance ();} catch (Sql::sqlexception &e) {perror ("drive connection error; \ n");} catch (Std::runtime_error &e) {perror ("Run error \ n");} This->initconnection (MAXSIZE/2);p thread_mutex_init (&lock, NULL);} Cconnpool *cconnpool::getinstance () {if (Connpool = = NULL) Connpool = new Cconnpool ("tcp://127.0.0.1:3306", "Root", " 123456 ","); return connpool;} void cconnpool::initconnection (int num) {Connection *conn;pthread_mutex_lock (&lock); for (int i = 0; i < num; ++i) {C Onn = CreateConnection (); if (conn) {connlist.push_back (conn); ++cursize;} Else{perror ("Error creating Connection");}} Pthread_mutex_unlock (&lock);} Connection *cconnpool::createconnection () {Connection *conn;try{conn = driver->connect (url, user, password);// Establish connection return conn;} catch (Sql::sqlexception &e) {perror (E.what ()); return NULL;} catch (Std::runtime_error &e) {perror (E.what ()); return NULL;}} Connection *cconnpool::getconnection () {Connection *conn;pthread_mutex_lock (&lock); if (connlist.size () > 0) { conn = Connlist.front (); Connlist.pop_front (), if (conn->isclosed ()) {Delete Conn;conn = CreateConnection ();} if (conn = = NULL)--cursize;pthread_mutex_unlock (&lock); return conn;} Else{if (Cursize < maxSize) {conn = CreateConnection (); if (conn) {++cursize;pthread_mutex_unlock (&lock); return Conn;} Else{pthread_mutex_unlock (&lock); return NULL;}} Else{pthread_mutex_unlock (&lock); return NULL;}}} void Cconnpool::releaseconnection (Connection *conn) {if (conn) {Pthread_mutex_lock (&lock); Connlist.push_back ( conn);p Thread_mutex_unlock (&lock);}} Cconnpool::~cconnpool () {This->destoryconnpool ();} void Cconnpool::D estoryconnpool () {list<connection *>::iterator iter;pthread_mutex_lock (&lock); for (iter = Connlist.begin (); Iter! = Connlist.end (); ++iter) this->destoryconnection (*iter), cursize = 0;connlist.clear ();p thread_mutex_unlock (&lock);} void Cconnpool::D estoryconnection (Connection *conn) {if (conn) {try{conn->close ();} catch (Sql::sqlexception &e) {perror (E.what ());} catch (Std::exception &e) {pError (E.what ());} Delete conn;}}

Main.cpp

#include <iostream> #include <string> #include "CConnPool.h" using std::cout;using std::endl;using std:: String Cconnpool *connpool = cconnpool::getinstance (); int main (int argc, char *argv[]) {    Connection *conn;    Statement *state;    ResultSet *result;    conn = Connpool->getconnection ();    State = Conn->createstatement ();    State->execute ("use MySQL");    result = State->executequery ("Select Host,user from User");    while (Result->next ())    {        try        {            String user = Result->getstring ("user");            String host = Result->getstring ("host");            cout << user << "@" << host << Endl;        }        catch (sql::sqlexception &e)        {            cout << e.what () << Endl;        }    }    Delete result;    Delete State;    Connpool->releaseconnection (conn);    GetChar ();    return 0;}

　　

Code sea supplements: MySQL-based connector/c++ MySQL operation (connection pooling)