最近事情比较多很久没有写学习笔记了,数据库线程池,+ 数据库封装,虽说数据库操作有很多不需要写sql 的,ORM 封装的方式去操作数据库。但是从业这些年一直是自己动手写sql ,还是改不了这个习惯。不说了直接上代码。
数据库线程池
ConnectionPool.h 文件#ifndef CONNECTIONPOOL_H
#define CONNECTIONPOOL_H#include <QtSql>
#include <QQueue>
#include <QString>
#include <QMutex>
#include <QMutexLocker>#include "ConnectionPool.h"class ConnectionPool {
public:static void release(); // 关闭所有的数据库连接static QSqlDatabase createConnection(); // 获取数据库连接static void closeConnection(QSqlDatabase connection); // 释放数据库连接回连接池~ConnectionPool();private:static ConnectionPool& getInstance();ConnectionPool();ConnectionPool(const ConnectionPool &other);ConnectionPool& operator=(const ConnectionPool &other);QSqlDatabase createConnection(const QString &connectionName); // 创建数据库连接void initialize();void loadConfigFile();public:QQueue<QString> usedConnectionNames; // 已使用的数据库连接名QQueue<QString> unusedConnectionNames; // 未使用的数据库连接名QJsonObject mJsonObject;// 数据库信息QString hostName;QString databaseName;QString username;QString password;QString databaseType;int port;bool testOnBorrow; // 取得连接的时候验证连接是否有效QString testOnBorrowSql; // 测试访问数据库的 SQLint maxWaitTime; // 获取连接最大等待时间int waitInterval; // 尝试获取连接时等待间隔时间int maxConnectionCount; // 最大连接数static QMutex mutex;static QWaitCondition waitConnection;static ConnectionPool *instance;
};#endif // CONNECTIONPOOL_H
ConnectionPool.cpp#include "ConnectionPool.h"
#include <QDebug>QMutex ConnectionPool::mutex;
QWaitCondition ConnectionPool::waitConnection;
ConnectionPool* ConnectionPool::instance = NULL;ConnectionPool::ConnectionPool()
{initialize();
}ConnectionPool::~ConnectionPool()
{// 销毁连接池的时候删除所有的连接foreach(QString connectionName, usedConnectionNames){QSqlDatabase::removeDatabase(connectionName);}foreach(QString connectionName, unusedConnectionNames){QSqlDatabase::removeDatabase(connectionName);}
}void ConnectionPool::loadConfigFile()
{QString path = qApp->applicationDirPath();QString strFile;strFile = path + "/config/DBConfig.json";QFile file(strFile);if(!file.open(QIODevice::ReadOnly | QIODevice::Text)){qDebug() << "could't open projects json";return;}QString value = file.readAll();file.close();QJsonParseError parseJsonErr;QJsonDocument document = QJsonDocument::fromJson(value.toUtf8(), &parseJsonErr);if(!(parseJsonErr.error == QJsonParseError::NoError)){qDebug() << parseJsonErr.errorString();return;}mJsonObject=document.object();
}void ConnectionPool::initialize()
{//loadConfigFile();hostName = "127.0.0.1";databaseName = "test";username = "root";password = "admin";databaseType = "QMYSQL";port = 3306;testOnBorrow = true;testOnBorrowSql = "SELECT 1";waitInterval = 200;maxWaitTime = 5000;maxConnectionCount = 10;}ConnectionPool& ConnectionPool::getInstance()
{if (NULL == instance){QMutexLocker locker(&mutex);if (NULL == instance){instance = new ConnectionPool();}}return *instance;
}void ConnectionPool::release()
{QMutexLocker locker(&mutex);delete instance;instance = NULL;
}QSqlDatabase ConnectionPool::createConnection()
{ConnectionPool& pool = ConnectionPool::getInstance();QString connectionName;QMutexLocker locker(&mutex);// 已创建连接数int connectionCount = pool.unusedConnectionNames.size() + pool.usedConnectionNames.size();// 如果连接已经用完,等待 waitInterval 毫秒看看是否有可用连接,最长等待 maxWaitTime 毫秒for (int i = 0;i < pool.maxWaitTime&& pool.unusedConnectionNames.size() == 0 && connectionCount == pool.maxConnectionCount;i += pool.waitInterval){waitConnection.wait(&mutex, pool.waitInterval);// 重新计算已创建连接数connectionCount = pool.unusedConnectionNames.size() + pool.usedConnectionNames.size();}qDebug() << "connectionCount:"<<connectionCount;qDebug() << "pool.maxConnectionCount:"<<pool.maxConnectionCount;if (pool.unusedConnectionNames.size() > 0){// 有已经回收的连接,复用它们connectionName = pool.unusedConnectionNames.dequeue();}else if (connectionCount < pool.maxConnectionCount){// 没有已经回收的连接,但是没有达到最大连接数,则创建新的连接connectionName = QString("Connection-%1").arg(connectionCount + 1);}else{// 已经达到最大连接数qDebug() << "Cannot create more connections.";return QSqlDatabase();}// 创建连接QSqlDatabase db = pool.createConnection(connectionName);// 有效的连接才放入 usedConnectionNamesif (db.isOpen()){pool.usedConnectionNames.enqueue(connectionName);}return db;
}void ConnectionPool::closeConnection(QSqlDatabase connection)
{ConnectionPool& pool = ConnectionPool::getInstance();QString connectionName = connection.connectionName();// 如果是我们创建的连接,从 used 里删除,放入 unused 里if (pool.usedConnectionNames.contains(connectionName)){QMutexLocker locker(&mutex);pool.usedConnectionNames.removeOne(connectionName);pool.unusedConnectionNames.enqueue(connectionName);waitConnection.wakeOne();}
}QSqlDatabase ConnectionPool::createConnection(const QString &connectionName)
{// 连接已经创建过了,复用它,而不是重新创建if (QSqlDatabase::contains(connectionName)){QSqlDatabase db1 = QSqlDatabase::database(connectionName);if (testOnBorrow){// 返回连接前访问数据库,如果连接断开,重新建立连接qDebug() << "Test connection on borrow, execute:" << testOnBorrowSql << ", for" << connectionName;QSqlQuery query(testOnBorrowSql, db1);if (query.lastError().type() != QSqlError::NoError && !db1.open()){qDebug() << "Open datatabase error:" << db1.lastError().text();return QSqlDatabase();}}return db1;}// 创建一个新的连接QSqlDatabase db = QSqlDatabase::addDatabase(databaseType, connectionName);db.setHostName(hostName);db.setDatabaseName(databaseName);db.setUserName(username);db.setPassword(password);db.setPort(port);if (!db.open()){qDebug() << "Open datatabase error:" << db.lastError().text();return QSqlDatabase();}return db;
}
数据库封装:
SqlDatabase.h#ifndef SQLDATABASE_H
#define SQLDATABASE_H#include <QJsonArray>
#include <QJsonValue>
#include <QJsonObject>class SqlDatabase
{
public:SqlDatabase();~SqlDatabase();public:static void InsertDB(QString strTableName,QJsonArray jsonValue);static void UpdateDB(QString strTableName,QJsonArray jsonValue,QString strColumnCondition);static int InsertDB(QString strTableName,QJsonObject jsonValue);static void UpdateDB(QString strTableName,QJsonObject jsonValue,QString strCondition);static void QueryRecord(QString strSql,QJsonArray &nJsonValue);static int QueryCount(QString strSql);static bool Delete(QString strSql);static bool Delete(QString strTableName,QString strCondition);
};#endif // SQLDATABASE_H
SqlDatabase.cpp#include "SqlDatabase.h"
#include "ConnectionPool.h"
#include <QDebug>#pragma execution_character_set("utf-8")SqlDatabase::SqlDatabase()
{}SqlDatabase::~SqlDatabase()
{ConnectionPool::Destroy();
}void SqlDatabase::InsertDB(QString strTableName,QJsonArray jsonValues)
{QSqlDatabase db =ConnectionPool::CreateConnection();QString strValues="";QString strNames="";bool iskeyName=false;for(int j=0;j<jsonValues.size();j++){QJsonObject::iterator it;QString strKeyValue;QJsonObject tmpObj =jsonValues.at(j).toObject();for(it=tmpObj.begin();it!=tmpObj.end();it++){if(strKeyValue.isEmpty()){if(it.value().isDouble()){it.value()=QString::number(it.value().toDouble(),'f',12);}strKeyValue=QString("'%1'").arg(it.value().toString());if(!iskeyName){strNames=QString("%1").arg(it.key());}}else{if(it.value().isDouble()){it.value()=QString::number(it.value().toDouble(),'f',12);}strKeyValue+=QString(",'%1'").arg(it.value().toString());if(!iskeyName){strNames+=QString(",%1").arg(it.key());}}}iskeyName =true;if(strValues.isEmpty()){strValues +="("+strKeyValue+")";}else{strValues +=",("+strKeyValue+")";}}QString strSql=QString("INSERT INTO %1 (%2) VALUES %3 ").arg(strTableName).arg(strNames).arg(strValues);QSqlQuery query(db);if(!query.exec(strSql)){qDebug()<<"Failed to INSERT:"<<strSql;}ConnectionPool::CloseConnection(db);
}void SqlDatabase::UpdateDB(QString strTableName,QJsonArray jsonValue,QString strColumnCondition)
{QString mHeadSql= QString(" UPDATE %1 m,( ").arg(strTableName);QString mEndSql=" ) n ";QString mSetConditionSql="";QString mValueSql="";QString mCondition="";QString strSql="";for(int i=0;i<jsonValue.size();i++){QJsonObject jsonObject=jsonValue.at(i).toObject();QJsonObject::iterator it;QString strValue="";if(!mValueSql.isEmpty()){mValueSql += " UNION ";}for(it=jsonObject.begin();it!=jsonObject.end();it++){if(it.value().isDouble()){it.value()=QString::number(it.value().toDouble(),'f',3);}if(strValue ==""){strValue =QString(" SELECT '%0' as `%1`").arg(it.value().toString()).arg(it.key());mSetConditionSql =QString(" SET m.%0 = n.%1").arg(it.key()).arg(it.key());}else{strValue +=QString(",'%0' as `%1`").arg(it.value().toString()).arg(it.key());mSetConditionSql += QString(" ,m.%0 = n.%1").arg(it.key()).arg(it.key());} }mValueSql += strValue;}mCondition += QString(" WHERE m.%0 = n.%1").arg(strColumnCondition).arg(strColumnCondition);strSql =mHeadSql +mValueSql + mEndSql + mSetConditionSql+ mCondition;qDebug()<<strSql;
}int SqlDatabase::InsertDB(QString strTableName,QJsonObject jsonValue)
{QSqlDatabase db =ConnectionPool::CreateConnection();QString strValues="";QString strNames="";int nLastNum=0;QJsonObject::iterator it;for(it=jsonValue.begin();it!=jsonValue.end();it++){if(strValues.isEmpty()){if(it.value().isDouble()){it.value()=QString::number(it.value().toDouble(),'f',12);}strValues=QString("'%1'").arg(it.value().toString());strNames=QString("%1").arg(it.key());}else{if(it.value().isDouble()){it.value()=QString::number(it.value().toDouble(),'f',12);}strValues+=QString(",'%1'").arg(it.value().toString());strNames+=QString(",%1").arg(it.key());}}QString strSql=QString("INSERT INTO %1 (%2) VALUES(%3) ").arg(strTableName).arg(strNames).arg(strValues);QSqlQuery query(db);if(!query.exec(strSql)){qDebug()<<"Failed to InsertDB:"<<query.lastError().text();}else{nLastNum=query.lastInsertId().toInt();}ConnectionPool::CloseConnection(db);return nLastNum;
}void SqlDatabase::UpdateDB(QString strTableName,QJsonObject jsonValue,QString strCondition)
{QSqlDatabase db =ConnectionPool::CreateConnection();QString strValues="";QString strNames="";QJsonObject::iterator it;for(it=jsonValue.begin();it!=jsonValue.end();it++){if(strValues.isEmpty()){if(it.value().isDouble()){it.value()=QString::number(it.value().toDouble(),'f',12);}strValues=QString("%1='%2'").arg(it.key()).arg(it.value().toString());}else{if(it.value().isDouble()){it.value()=QString::number(it.value().toDouble(),'f',12);}strValues+=QString(",%1='%2'").arg(it.key()).arg(it.value().toString());}}QString strSql=QString("UPDATE %1 SET %2 %3 ").arg(strTableName).arg(strValues).arg(strCondition);QSqlQuery query(db);if(!query.exec(strSql)){qDebug()<<"Failed to UpdateDB:"<<query.lastError().text();}ConnectionPool::CloseConnection(db);
}void SqlDatabase::QueryRecord(QString strSql,QJsonArray &nJsonValue)
{QSqlDatabase db =ConnectionPool::CreateConnection();QSqlQuery query(db);if(!query.exec(strSql)){qDebug()<<"Failed to QueryRecord:"<<query.lastError().text();}while(query.next()){QSqlRecord qResultRecord=query.record();QJsonObject jsonObject;for(int fileIndex =0; fileIndex<qResultRecord.count();fileIndex++){if(query.value(fileIndex).isNull()){jsonObject.insert(qResultRecord.fieldName(fileIndex),QJsonValue::Null);}else if(query.value(fileIndex).type() ==QVariant::Int){jsonObject.insert(qResultRecord.fieldName(fileIndex),query.value(fileIndex).toInt());}else if(query.value(fileIndex).type() == QVariant::Double){jsonObject.insert(qResultRecord.fieldName(fileIndex),query.value(fileIndex).toDouble());}else if(query.value(fileIndex).type() == QVariant::LongLong){jsonObject.insert(qResultRecord.fieldName(fileIndex),query.value(fileIndex).toLongLong());}else{jsonObject.insert(qResultRecord.fieldName(fileIndex),query.value(fileIndex).toString());}}nJsonValue.append(jsonObject);}ConnectionPool::CloseConnection(db);
}int SqlDatabase::QueryCount(QString strSql)
{QSqlDatabase db =ConnectionPool::CreateConnection();QSqlQuery query(db);int totalCnt=0;QString strSqlCount=QString(" SELECT COUNT(*) AS Cnt FROM (%1) t ").arg(strSql);if(!query.exec(strSqlCount)){qDebug()<<"Failed to QueryCount:"<<query.lastError().text();}while(query.next()){totalCnt=query.value("Cnt").toInt();}ConnectionPool::CloseConnection(db);return totalCnt;
}bool SqlDatabase::Delete(QString strSql)
{bool bRet =true;QSqlDatabase db =ConnectionPool::CreateConnection();QSqlQuery query(db);if(!query.exec(strSql)){qDebug()<<"Failed to Delete:"<<query.lastError().text();bRet = false;}ConnectionPool::CloseConnection(db);return bRet;
}bool SqlDatabase::Delete(QString strTableName,QString strCondition)
{bool bRet =true;QSqlDatabase db =ConnectionPool::CreateConnection();QSqlQuery query(db);QString strSql=QString(" DELETE FROM %1 %2 ").arg(strTableName).arg(strCondition);if(!query.exec(strSql)){qDebug()<<"Failed to Delete:"<<query.lastError().text();bRet = false;}ConnectionPool::CloseConnection(db);return bRet;
}
此处说一下批量更新
源数据是这样需要更新
id:1 shorName :aaaaa score1:56.9 ranking :22
id:2 shorName :bbbbb score1:89.9 score3:59.9 ranking :27
id:3 shorName :ccccc score1:76.9 score2:81.9 ranking :29
sql 语句 批量更新
UPDATE test m,(SELECT'1.000' AS `id`,'a' AS `name`,'22.000' AS `ranking`,'56.900' AS `score1`,'39.500' AS `score2`,'56.700' AS `score3`,'aaaa' AS `shorName` UNIONSELECT'2.000' AS `id`,'b' AS `name`,'27.000' AS `ranking`,'89.900' AS `score1`,'39.500' AS `score2`,'59.900' AS `score3`,'bbbbb' AS `shorName` UNIONSELECT'3.000' AS `id`,'c' AS `name`,'29.000' AS `ranking`,'76.900' AS `score1`,'72.900' AS `score2`,'81.900' AS `score3`,'ccccc' AS `shorName` ) n SET m.id = n.id,m.NAME = n.NAME,m.ranking = n.ranking,m.score1 = n.score1,m.score2 = n.score2,m.score3 = n.score3,m.shorName = n.shorName
WHEREm.id = n.id