Linux下C++访问MySQL<一>

/*
配置开发环境
首先需要编译、安装MySQL，安装完成后，将MySQL目录中的lib目录添加到环境变量中。

新建C/C++工程，把$MYSQL_ROOT/include添加到编译环境的包含路径下面。在编译选项中，增加$MYSQL_ROOT/lib目录。在Link选项中增加-lmysqlclient（已经把lib目录增加到系统环境变量中），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);            //    设置主机IP地址   
        this -> setUserName( userName);            //    设置登录用户名   
        this -> setPassword( password);            //    设置登录密码   
        this -> setDBName( dbName);            //    设置数据库名   
        this -> setPort( port);            //    设置端口号   
}  

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

void MySQLManager :: setDBName( string dbName)   
{   
        if ( dbName . empty() )   
        { //        用户没有指定数据库名   
                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() )   
        { //    用户没有指定数据库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)   
{ //    用户没有指定密码   
        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)   
{ //    用户没有指定端口号，使用默认端口号   
        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)   
{ //    用户没有指定登录用户名   
        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 )   
        { //    已经连接到服务器   
                std :: cout << "Is connected to server!" << std :: endl;   
                return;   
        }   
        mysql_init( & mySQLClient); //    初始化相关对象   
        if ( ! mysql_real_connect( & mySQLClient , HOSTS , USERNAME , PASSWORD , DBNAME , DEFAULTPORT , NULL , 0) )   
        { //    连接到服务器   
                std :: cout << "Error connection to database: %s \n " << mysql_error( & mySQLClient) << std :: endl;   
        }   
        IsConnected = true; //    修改连接标识   
}  

bool MySQLManager :: runSQLCommand( string sql)   
{   
        if ( ! IsConnected )   
        { //    没有连接到服务器   
                std :: cout << "Not connect to database!" << std :: endl;   
                return false;   
        }   
        if ( sql . empty() )   
        { //    SQL语句为空   
                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())); //    执行查询   
        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)) )   
        { //    遍历结果集   
                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;   
}