关于QTcpSocket的问题

[AAA20090987]

//client.h
#ifndef CLIENT_H
#define CLIENT_H

#include <QDialog>
#include <QTcpSocket>

QT_BEGIN_NAMESPACE
class QDialogButtonBox;
class QLabel;
class QLineEdit;
class QPushButton;
class QTcpSocket;
class QTextEdit;
QT_END_NAMESPACE

//! [0]
class Client : public QDialog
{
	Q_OBJECT

public:
	Client(QWidget *parent = 0);

	private slots:
		void requestNewFortune();
		void readFortune();
		void displayError(QAbstractSocket::SocketError socketError);
		void enableGetFortuneButton();

private:
	QLabel *hostLabel;
	QLabel *portLabel;
	QLineEdit *hostLineEdit;
	QLineEdit *portLineEdit;
	QTextEdit *textEdit;
	QPushButton *getFortuneButton;
	QPushButton *quitButton;
	QDialogButtonBox *buttonBox;

	QTcpSocket *tcpSocket;
	QString currentFortune;
	quint16 blockSize;
#ifdef Q_OS_SYMBIAN
	bool isDefaultIapSet;
#endif
};
//! [0]

#endif


//client.cpp
#include <QtGui>
#include <QtNetwork>

#include "client.h"

#ifdef Q_OS_SYMBIAN
#include "sym_iap_util.h"
#endif

//! [0]
Client::Client(QWidget *parent)
: QDialog(parent)
{
	//! [0]
	hostLabel = new QLabel(tr("&Server name:"));
	portLabel = new QLabel(tr("S&erver port:"));

	// find out which IP to connect to
	QString ipAddress;
	QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();
	// use the first non-localhost IPv4 address
	for (int i = 0; i < ipAddressesList.size(); ++i) {
		if (ipAddressesList.at(i) != QHostAddress::LocalHost &&
			ipAddressesList.at(i).toIPv4Address()) {
				ipAddress = ipAddressesList.at(i).toString();
				break;
		}
	}
	// if we did not find one, use IPv4 localhost
	if (ipAddress.isEmpty())
		ipAddress = QHostAddress(QHostAddress::LocalHost).toString();

	hostLineEdit = new QLineEdit(ipAddress);
	portLineEdit = new QLineEdit;
	portLineEdit->setValidator(new QIntValidator(1, 65535, this));

	hostLabel->setBuddy(hostLineEdit);
	portLabel->setBuddy(portLineEdit);

	textEdit = new QTextEdit;
	textEdit->setReadOnly(true);
	textEdit->append("This examples requires that you run the "
		"Fortune Server example as well.");

	getFortuneButton = new QPushButton(tr("Get Fortune"));
	getFortuneButton->setDefault(true);
	getFortuneButton->setEnabled(false);

	quitButton = new QPushButton(tr("Quit"));

	buttonBox = new QDialogButtonBox;
	buttonBox->addButton(getFortuneButton, QDialogButtonBox::ActionRole);
	buttonBox->addButton(quitButton, QDialogButtonBox::RejectRole);

	//! [1]
	tcpSocket = new QTcpSocket(this);
	//! [1]

	connect(hostLineEdit, SIGNAL(textChanged(QString)),
		this, SLOT(enableGetFortuneButton()));
	connect(portLineEdit, SIGNAL(textChanged(QString)),
		this, SLOT(enableGetFortuneButton()));
	connect(getFortuneButton, SIGNAL(clicked()),
		this, SLOT(requestNewFortune()));
	connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
	//! [2] //! [3]
	connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(readFortune()));
	//! [2] //! [4]
	connect(tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)),
		//! [3]
		this, SLOT(displayError(QAbstractSocket::SocketError)));
	//! [4]

	QGridLayout *mainLayout = new QGridLayout;
	mainLayout->addWidget(hostLabel, 0, 0);
	mainLayout->addWidget(hostLineEdit, 0, 1);
	mainLayout->addWidget(portLabel, 1, 0);
	mainLayout->addWidget(portLineEdit, 1, 1);
	mainLayout->addWidget(textEdit, 2, 0, 3, 2);
	mainLayout->addWidget(buttonBox, 5, 0, 1, 2);
	setLayout(mainLayout);

	setWindowTitle(tr("Fortune Client"));
	portLineEdit->setFocus();

}

//主要是这个函数改了
void Client::requestNewFortune()
{
	getFortuneButton->setEnabled(false);
	for(int i=0;i<5;i++)
	{
		blockSize = 0;
		tcpSocket->abort();
		tcpSocket->connectToHost(hostLineEdit->text(),
			portLineEdit->text().toInt());
	}
}
//! [6]

//! [8]
void Client::readFortune()
{
	//! [9]
	QDataStream in(tcpSocket);
	in.setVersion(QDataStream::Qt_4_0);

	if (blockSize == 0) {
		if (tcpSocket->bytesAvailable() < (int)sizeof(quint16))
			return;
		//! [8]

		//! [10]
		in >> blockSize;
	}

	if (tcpSocket->bytesAvailable() < blockSize)
		return;
	//! [10] //! [11]

	QString nextFortune;
	in >> nextFortune;

	if (nextFortune == currentFortune) {
		QTimer::singleShot(0, this, SLOT(requestNewFortune()));
		return;
	}
	//! [11]

	//! [12]
	currentFortune = nextFortune;
	//! [9]
	textEdit->append(currentFortune);
	getFortuneButton->setEnabled(true);
}
//! [12]

//! [13]
void Client::displayError(QAbstractSocket::SocketError socketError)
{
	switch (socketError) {
	case QAbstractSocket::RemoteHostClosedError:
		break;
	case QAbstractSocket::HostNotFoundError:
		QMessageBox::information(this, tr("Fortune Client"),
			tr("The host was not found. Please check the "
			"host name and port settings."));
		break;
	case QAbstractSocket::ConnectionRefusedError:
		QMessageBox::information(this, tr("Fortune Client"),
			tr("The connection was refused by the peer. "
			"Make sure the fortune server is running, "
			"and check that the host name and port "
			"settings are correct."));
		break;
	default:
		QMessageBox::information(this, tr("Fortune Client"),
			tr("The following error occurred: %1.")
			.arg(tcpSocket->errorString()));
	}

	getFortuneButton->setEnabled(true);
}
//! [13]

void Client::enableGetFortuneButton()
{
	getFortuneButton->setEnabled(!hostLineEdit->text().isEmpty()
		&& !portLineEdit->text().isEmpty());
}


//main.cpp
#include <QApplication>
#include "client.h"

int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
	Client client;
#ifdef Q_OS_SYMBIAN
	// Make application better looking and more usable on small screen
	client.showMaximized();
#else
	client.show();
#endif
	return client.exec();
}

这个程序是由QT自带例子fortune client改编之成的，服务器是QT的自带例子fortune server

程序的功能是在我按下发送按钮的时候，向服务器连续发送5个请求，
但客户端只能收到一条信息（本来应该收到5条信息的），这是为什么呢？
应该怎样改正？

PS：祝大家新年快乐！

[写不动代码的人]

检查一下服务端是否收到5个请求

[AAA20090987]

这是服务器端的代码：

//server.h
#ifndef SERVER_H
#define SERVER_H

#include <QDialog>

QT_BEGIN_NAMESPACE
class QLabel;
class QPushButton;
class QTcpServer;
QT_END_NAMESPACE

//! [0]
class Server : public QDialog
{
	Q_OBJECT

public:
	Server(QWidget *parent = 0);

	private slots:
		void sendFortune();

private:
	QLabel *statusLabel;
	QPushButton *quitButton;
	QTcpServer *tcpServer;
	QStringList fortunes;
};
//! [0]

#endif



//server.cpp
#include <QtGui>
#include <QtNetwork>

#include "fserver.h"

Server::Server(QWidget *parent)
: QDialog(parent)
{
	statusLabel = new QLabel;
	quitButton = new QPushButton(tr("Quit"));
	quitButton->setAutoDefault(false);

	tcpServer = new QTcpServer(this);
	if (!tcpServer->listen()) {
		QMessageBox::critical(this, tr("Fortune Server"),
			tr("Unable to start the server: %1.")
			.arg(tcpServer->errorString()));
		close();
		return;
	}
	//! [0]
	QString ipAddress;
	QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();
	// use the first non-localhost IPv4 address
	for (int i = 0; i < ipAddressesList.size(); ++i) {
		if (ipAddressesList.at(i) != QHostAddress::LocalHost &&
			ipAddressesList.at(i).toIPv4Address()) {
				ipAddress = ipAddressesList.at(i).toString();
				break;
		}
	}
	// if we did not find one, use IPv4 localhost
	if (ipAddress.isEmpty())
		ipAddress = QHostAddress(QHostAddress::LocalHost).toString();
	statusLabel->setText(tr("The server is running on\n\nIP: %1\nport: %2\n\n"
		"Run the Fortune Client example now.")
		.arg(ipAddress).arg(tcpServer->serverPort()));
	//! [1]

	//! [2]
	fortunes << tr("You've been leading a dog's life. Stay off the furniture.")
		<< tr("You've got to think about tomorrow.")
		<< tr("You will be surprised by a loud noise.")
		<< tr("You will feel hungry again in another hour.")
		<< tr("You might have mail.")
		<< tr("You cannot kill time without injuring eternity.")
		<< tr("Computers are not intelligent. They only think they are.");
	//! [2]

	connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
	//! [3]
	connect(tcpServer, SIGNAL(newConnection()), this, SLOT(sendFortune()));
	//! [3]

	QHBoxLayout *buttonLayout = new QHBoxLayout;
	buttonLayout->addStretch(1);
	buttonLayout->addWidget(quitButton);
	buttonLayout->addStretch(1);

	QVBoxLayout *mainLayout = new QVBoxLayout;
	mainLayout->addWidget(statusLabel);
	mainLayout->addLayout(buttonLayout);
	setLayout(mainLayout);

	setWindowTitle(tr("Fortune Server"));
}

//! [4]
void Server::sendFortune()
{
	//! [5]
	QByteArray block;
	QDataStream out(&block, QIODevice::WriteOnly);
	out.setVersion(QDataStream::Qt_4_0);
	out << (quint16)0;
	out << fortunes.at(qrand() % fortunes.size());
	out.device()->seek(0);
	out << (quint16)(block.size() - sizeof(quint16));

	QTcpSocket *clientConnection = tcpServer->nextPendingConnection();

	connect(clientConnection, SIGNAL(disconnected()),
		clientConnection, SLOT(deleteLater()));
	//! [7] //! [8]

	clientConnection->write(block);
	clientConnection->disconnectFromHost();
	//! [5]
}
//! [8]



//main.cpp
#include <QApplication>
#include <QtCore>

#include "fserver.h"

#ifdef Q_OS_SYMBIAN
#include "sym_iap_util.h"
#endif

int main(int argc, char *argv[])
{
#ifdef Q_OS_SYMBIAN
	qt_SetDefaultIap();
#endif
	QApplication app(argc, argv);
	Server server;
#ifdef Q_OS_SYMBIAN
	server.showMaximized();
#else
	server.show();
#endif
	qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
	return server.exec();
}

[AAA20090987]

[Quote=引用 1 楼 heksn 的回复:]
检查一下服务端是否收到5个请求
[/Quote]

我调试了一下，服务器的确收到了5个请求

[人到中年琐事多]

关键是你那个For循环里有问题,要注意网络流往返的速度可赶不上for循环的速度:
for(int i=0;i<5;i++)
{
blockSize = 0;
tcpSocket->abort();//tcpSocket未完成任务就重置连接了
tcpSocket->connectToHost(hostLineEdit->text(),
portLineEdit->text().toInt());
tcpSocket->waitForReadyRead(1000);//阻塞一下就行了(等待tcpSocket从服务器获取数据)
}

[AAA20090987]

[Quote=引用 4 楼 yangglemu 的回复:]

关键是你那个For循环里有问题,要注意网络流往返的速度可赶不上for循环的速度:
for(int i=0;i<5;i++)
{
blockSize = 0;
tcpSocket->abort();//tcpSocket未完成任务就重置连接了
tcpSocket->connectToHost(hostLineEdit->text(),
portLi……
[/Quote]

解决了，谢谢你啊
我当时也在郁闷，怎么QT的网络库都是非阻塞的呢？呵呵

你已经帮过我很多次了，再次谢谢你。