Linux下C++訪問MySQL<一>

/*
配置開發環境
首先需要編譯、安裝MySQL，安裝完成後，將MySQL目錄中的lib目錄添加到環境變量中。

新建C/C++工程，把$MYSQL_ROOT/include添加到編譯環境的包含路徑下面。在編譯選項中，增加$MYSQL_ROOT/lib目錄。在Link選項中增加-lmysqlclient（已經把lib目錄增加到系統環境變量中），或者直接引用libmysqlclient.so文件。
*/


#ifndef MYSQLMANAGER_H_   
#define MYSQLMANAGER_H_  

#include "../Common/CheckStringTools.h"  

#include <mysql.h>  

#include <string>   
#include <iostream>   
#include <vector>  

#include <string.h>  

using namespace std;  

class MySQLManager   
{   
public:   
        /*   
         * Init MySQL   
         * @param hosts:         Host IP address   
         * @param userName:        Login UserName   
         * @param password:        Login Password   
         * @param dbName:        Database Name   
         * @param port:                Host listen port number   
         */   
        MySQLManager(std::string hosts, std::string userName, std::string password, std::string dbName, unsigned int port);   
        ~MySQLManager();   
        void initConnection();   
        /*   
         * Making query from database   
         * @param mysql:        MySQL Object   
         * @param sql:                Running SQL command   
         */   
        bool runSQLCommand(std::string sql);   
        /**   
         * Destroy MySQL object   
         * @param mysql                MySQL object   
         */   
        void destroyConnection();   
        bool getConnectionStatus();   
        vector< vector<string> > getResult();   
protected:   
        void setUserName(std::string userName);   
        void setHosts(std::string hosts);   
        void setPassword(std::string password);   
        void setDBName(std::string dbName);   
        void setPort(unsigned int port);   
private:   
        bool IsConnected;   
        vector< vector<string> > resultList;   
        MYSQL mySQLClient;   
        unsigned int DEFAULTPORT;   
        char * HOSTS;   
        char * USERNAME;   
        char * PASSWORD;   
        char * DBNAME;   
};  

#endif /* MYSQLMANAGER_H_ */

 
#include "MySQLManager.h"  

MySQLManager::MySQLManager(string hosts, string userName, string password, string dbName, unsigned int port)   
{   
        IsConnected = false;   
        this ->setHosts(hosts);            //    設置主機IP地址   
        this ->setUserName(userName);            //    設置登錄用戶名   
        this ->setPassword(password);            //    設置登錄密碼   
        this ->setDBName(dbName);            //    設置數據庫名   
        this ->setPort(port);            //    設置端口號   
}  

MySQLManager::~MySQLManager()   
{   
        this ->destroyConnection();   
}  

void MySQLManager::setDBName(string dbName)   
{   
        if ( dbName.empty() )   
        {//        用戶沒有指定數據庫名   
                std::cout << "DBName is null! Used default value: mysql" << std::endl;   
                this ->DBNAME = new char[5];   
                strcpy(this ->DBNAME, "mysql");   
        }   
        else   
        {   
                this ->DBNAME = new char[dbName.length()];   
                strcpy(this ->DBNAME, dbName.c_str());   
        }   
}  

void MySQLManager::setHosts(string hosts)   
{   
        if ( hosts.empty() )   
        {//    用戶沒有指定數據庫IP地址   
                std::cout << "Hosts is null! Used default value: localhost" << std::endl;   
                this ->HOSTS = new char[9];   
                strcpy(this ->HOSTS, "localhost");   
        }   
        else   
        {   
                this ->HOSTS = new char[hosts.length()];   
                strcpy(this ->HOSTS, hosts.c_str());   
        }   
}  

void MySQLManager::setPassword(string password)   
{//    用戶沒有指定密碼   
        if ( password.empty() )   
        {   
                std::cout << "Password is null! Used default value: " << std::endl;   
                this ->PASSWORD = new char[1];   
                strcpy(this ->PASSWORD, "");   
        }   
        else   
        {   
                this ->PASSWORD = new char[password.length()];   
                strcpy(this ->PASSWORD, password.c_str());   
        }   
}  

void MySQLManager::setPort(unsigned int port)   
{//    用戶沒有指定端口號，使用默認端口號   
        if ( port )   
        {   
                std::cout << "Port number is null! Used default value: 0" << std::endl;   
                this ->DEFAULTPORT = 0;   
        }   
        else   
        {   
                this ->DEFAULTPORT = port;   
        }   
}  

void MySQLManager::setUserName(string userName)   
{//    用戶沒有指定登錄用戶名   
        if ( userName.empty() )   
        {   
                std::cout << "UserName is null! Used default value: root" << std::endl;   
                this ->USERNAME = new char[4];   
                strcpy(this ->USERNAME, "root");   
        }   
        else   
        {   
                this ->USERNAME = new char[userName.length()];   
                strcpy(this ->USERNAME, userName.c_str());   
        }   
}  

void MySQLManager::initConnection()   
{   
        if ( IsConnected )   
        {//    已經連接到服務器   
                std::cout << "Is connected to server!" <<std::endl;   
                return;   
        }   
        mysql_init(&mySQLClient);//    初始化相關對象   
        if ( !mysql_real_connect( &mySQLClient, HOSTS, USERNAME, PASSWORD, DBNAME, DEFAULTPORT, NULL, 0) )   
        {//    連接到服務器   
                std::cout << "Error connection to database: %s\n" << mysql_error(&mySQLClient) << std::endl;   
        }   
        IsConnected = true;//    修改連接標識   
}  

bool MySQLManager::runSQLCommand(string sql)   
{   
        if ( !IsConnected )   
        {//    沒有連接到服務器   
                std::cout << "Not connect to database!" << std::endl;   
                return false;   
        }   
        if ( sql.empty() )   
        {//    SQL語句爲空   
                std::cout << "SQL is null!" << std::endl;   
                return false;   
        }  

        MYSQL_RES *res;   
        MYSQL_ROW row;  

        unsigned int i,j = 0;  

        StringTools stringTools;   
        sql = stringTools.filterString(sql);  

        i = mysql_real_query(&mySQLClient,sql.c_str(),(unsigned int)strlen(sql.c_str()));//    執行查詢   
        if ( i )   
        {   
                std::cout << "Error query from database: %s\n" << mysql_error(&mySQLClient) << std::endl;   
                return false;   
        }   
        res = mysql_store_result(&mySQLClient);   
        vector<string> objectValue;   
        while( (row = mysql_fetch_row(res)) )   
        {//    遍歷結果集   
                objectValue.clear();   
                for ( j = 0 ; j < mysql_num_fields(res) ; j++ )   
                {   
                        objectValue.push_back(row[j]);   
                }   
                this ->resultList.push_back(objectValue);   
        }   
        mysql_free_result(res);         //free result after you get the result  

        return true;   
}  

vector< vector<string> > MySQLManager::getResult()   
{   
        return resultList;   
}  

void MySQLManager::destroyConnection()   
{   
        mysql_close(&mySQLClient);   
        this ->IsConnected = false;   
}  

bool MySQLManager::getConnectionStatus()   
{   
        return IsConnected;   
}