Qt实现简单的TCP网络电子词典（带界面，能并发）

服务器代码：

#include "dialog.h"


Dialog::Dialog(QWidget *parent)
    : QDialog(parent)
{
    tcpServer=new QTcpServer(this);
    tcpServer->listen(QHostAddress::Any,6677);
    connect(tcpServer,SIGNAL(newConnection()),this,SLOT(newClient()));
    QSqlDatabase db=QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName("my.db");
    db.open();
}


Dialog::~Dialog()
{


}


void Dialog::newClient()
{
    nextBlockSize=0;
    QTcpSocket *tcpSocket=tcpServer->nextPendingConnection();
    connect(tcpSocket,SIGNAL(readyRead()),this,SLOT(readClient()));
    connect(tcpSocket,SIGNAL(disconnected()),tcpSocket,SLOT(deleteLater()));
}


void Dialog::readClient()
{
    QTcpSocket *tcpSocket=qobject_cast(sender());
    QDataStream in(tcpSocket);
    if(nextBlockSize==0) {
        if(tcpSocket->bytesAvailable() < sizeof(quint16))
            return;
        in >> nextBlockSize;
    }
    if(tcpSocket->bytesAvailable() < nextBlockSize)
        return;
    quint8 type;
    QString username,password,word;
    in >> type;
    if(type!='Q') {
        in >> username >> password;
        processLogin(tcpSocket,type,username,password);
    }else {
        in >> word;
        processFind(tcpSocket,word);
    }
    tcpSocket->close();
}


void Dialog::processLogin(QTcpSocket *tcpSocket, quint8 type, QString &username, QString password)
{
    QByteArray buf;
    QDataStream out(&buf,QIODevice::WriteOnly);
    out << quint16(0) << quint8(type);
    QSqlQuery query("select * from users");
    QString user,pass;
    if(type=='L') {
        while(query.next()) {
            user=query.value(0).toString();
            pass=query.value(1).toString();
            if((user == username) && (pass == password)) {
                out << QString("OK");
                out.device()->seek(0);
                tcpSocket->write(buf);
                return;
            }
        }
        out << QString("Failed");
        out.device()->seek(0);
        tcpSocket->write(buf);
    }
    else if(type=='R') {
        while(query.next()) {
            user=query.value(0).toString();
            if(user == username) {
                out << QString("Failed");
                out.device()->seek(0);
                out << quint16(buf.size()-sizeof(quint16));
                tcpSocket->write(buf);
                return;
            }
        }
        query.exec(QString("insert into users values(\"%1\",\"%2\")").arg(username).arg(password));


        out << QString("OK");
        out.device()->seek(0);
        out << quint16(buf.size()-sizeof(quint16));
        tcpSocket->write(buf);
    }
}


void Dialog::processFind(QTcpSocket *tcpSocket, QString &word)
{
    QByteArray buf;
    QDataStream out(&buf,QIODevice::WriteOnly);
    out << quint16(0) << quint8('R');


    QFile file("dict.txt");
    if(!file.open(QIODevice::ReadOnly|QIODevice::Text)) {
        qDebug() << "open dict.txt failed";
        return;
    }
    QString line;
    QTextStream in(&file);
    while(!in.atEnd()) {
        line=in.readLine();
        if(line.startsWith(word)) {
            word=line.mid(word.length());
            word=word.trimmed();
            out << word;
            out.device()->seek(0);
            out << quint16(buf.size()-sizeof(quint16));
            tcpSocket->write(buf);
            return;
        }
    }
    word="word not found";
    out << word;
    out.device()->seek(0);
    out << quint16(buf.size()-sizeof(quint16));
    tcpSocket->write(buf);
    return;
}

===============================================================================================================================

#include "logindialog.h"
#include "ui_logindialog.h"


LoginDialog::LoginDialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::LoginDialog)
{
    ui->setupUi(this);
    tcpSocket=new QTcpSocket(this);
    connect(tcpSocket,SIGNAL(connected()),this,SLOT(sendRequest()));
    connect(tcpSocket,SIGNAL(readyRead()),this,SLOT(readResponse()));
}


LoginDialog::~LoginDialog()
{
    delete ui;
}


void LoginDialog::on_buttonBox_accepted()
{
    nextBlockSize=0;
    tcpSocket->connectToHost("127.0.0.1",6677);
}


void LoginDialog::readResponse()
{
    QDataStream in(tcpSocket);
    if(nextBlockSize==0) {
        if(tcpSocket->bytesAvailable() < sizeof(quint16))
            return;
        in >> nextBlockSize;
    }
    if(tcpSocket->bytesAvailable() < nextBlockSize)
        return;
    quint8 type;
    QString str;
    in >> type >> str;
    tcpSocket->close();
    if(type=='R' && str=="OK") {
        QMessageBox::information(this,"success","register OK");
    }else if(type=='R') {
        QMessageBox::warning(this,"error","register failed");
    }
    if(type=='L' && str=="OK") {
        FindDialog *dialog=new FindDialog;
        dialog->show();
        hide();
    }else if(type=='L') {
        QMessageBox::warning(this,"error","login error");
    }
}


void LoginDialog::sendRequest()
{
    QByteArray buf;
    QDataStream out(&buf,QIODevice::WriteOnly);
    out << quint16(0);
    if(ui->radioButton->isChecked())
        out << quint8('L');
    else
        out << quint8('R');
    out << ui->lineEdit->text() << ui->lineEdit_2->text();
    out.device()->seek(0);
    out << quint16(buf.size()-sizeof(quint16));
    tcpSocket->write(buf);
}

=================================================================================================================================

#include "finddialog.h"
#include "ui_finddialog.h"


FindDialog::FindDialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::FindDialog)
{
    ui->setupUi(this);
    tcpSocket=new QTcpSocket(this);
    connect(tcpSocket,SIGNAL(readyRead()),this,SLOT(readResponse()));
    connect(tcpSocket,SIGNAL(connected()),this,SLOT(sendRequest()));
}


FindDialog::~FindDialog()
{
    delete ui;
}


void FindDialog::on_pushButton_clicked()
{
    tcpSocket->connectToHost("127.0.0.1",6677);
    nextBlockSize=0;
}


void FindDialog::sendRequest()
{
    QByteArray buf;
    QDataStream out(&buf,QIODevice::WriteOnly);
    out << quint16(0) << quint8('Q') << ui->lineEdit->text();
    out.device()->seek(0);
    out << quint16(buf.size()-sizeof(quint16));
    tcpSocket->write(buf);
}


void FindDialog::readResponse()
{
    QDataStream in(tcpSocket);
    if(nextBlockSize==0) {
        if(tcpSocket->bytesAvailable() < sizeof(quint16))
            return;
        in >> nextBlockSize;
    }
    if(tcpSocket->bytesAvailable() < nextBlockSize)
        return;
    quint8 type;
    QString str;
    in >> type >> str;
    if(type=='R')
        ui->textBrowser->setText(str);
    tcpSocket->close();
}