Qt使用QTcpSocket及QTcpServer传输文件

服务端具体代码如下：

.h
#include <QTcpServer>
#include <QTcpSocket>
#include <QFileDialog>
#include <QFile>
#define BUF_SIZE 1024*8
class ServerProject : public QWidget
{
    Q_OBJECT

public:
    ServerProject(QWidget *parent = nullptr);
    ~ServerProject();
    void iniServer();
    void closeServer();
    void sendData();
private slots:
    void on_listenBtn_clicked();
    void on_sendBtn_clicked();
    void on_clearRecBtn_clicked();
    void on_selectBtn_clicked();
    void on_sendFileBtn_clicked();
    void newConnectionSlot();
    void readyReadSlot();
private:
    Ui::ServerProjectClass ui;
	QTcpServer* m_server;
    QTcpSocket* m_socket;
    QString m_filename;
    int m_fileSize, m_sendSize;
    QFile m_file;
};
.cpp
ServerProject::ServerProject(QWidget *parent)
    : QWidget(parent)
{
    ui.setupUi(this);
    setWindowTitle("Server");
    iniServer();
}
ServerProject::~ServerProject()
{
	closeServer();
	if (m_socket != NULL) {
		delete m_socket;
		m_socket = NULL;
	}
}
void ServerProject::iniServer() {
	//m_sendEnable = false;
	m_filename = "";
	m_fileSize = 0;
	m_sendSize = 0;
	m_socket = NULL;
	ui.clearRecBtn->setEnabled(false);
	ui.sendBtn->setEnabled(false);
	ui.selectBtn->setEnabled(false);
	ui.sendFileBtn->setEnabled(false);
    m_server = new QTcpServer(this);
}
void ServerProject::closeServer() {
	m_server->close();
	if (m_socket == NULL) {
		return;
	}
	//断开与客户端的连接
	if (m_socket->state() == QAbstractSocket::ConnectedState) {
		m_socket->disconnectFromHost();
		if (m_socket->state() != QAbstractSocket::UnconnectedState) {
			m_socket->abort();
		}
	}
}
void ServerProject::on_listenBtn_clicked() {
	if (m_server->isListening()) {
		closeServer();
		//关闭server后恢复界面状态
		ui.listenBtn->setText("Listen");
		ui.addressEt->setEnabled(true);
		ui.portEt->setEnabled(true);
	}
	else {
		//可以使用 QHostAddress::Any 监听所有地址的对应端口
		const QString address_text = ui.addressEt->text();
		const unsigned short port = ui.portEt->text().toUShort();
		const QHostAddress address = (address_text == "Any")
			? QHostAddress::Any
			: QHostAddress(address_text);
		//开始监听，并判断是否成功
		if (m_server->listen(address, port)) {
			//连接成功就修改界面按钮提示，以及地址栏不可编辑
			ui.listenBtn->setText("Close");
			ui.addressEt->setEnabled(false);
			ui.portEt->setEnabled(false);
		}
		connect(m_server, &QTcpServer::newConnection, this, &ServerProject::newConnectionSlot);
	}
}
void ServerProject::newConnectionSlot() {
	if (m_server->hasPendingConnections())
	{
		//nextPendingConnection返回下一个挂起的连接作为已连接的QTcpSocket对象
		//套接字是作为服务器的子级创建的，这意味着销毁QTcpServer对象时会自动删除该套接字。
		//最好在完成处理后显式删除该对象，以避免浪费内存。
		//返回的QTcpSocket对象不能从另一个线程使用，如有需要可重写incomingConnection().
		m_socket = m_server->nextPendingConnection();
		ui.receiveEt->append("connected.........");
		connect(m_socket, &QTcpSocket::readyRead, this, &ServerProject::readyReadSlot);
		ui.clearRecBtn->setEnabled(true);
		ui.selectBtn->setEnabled(true);
		ui.sendBtn->setEnabled(true);
	}
}
void ServerProject::readyReadSlot() {
	if (m_socket->bytesAvailable() <= 0)
		return;
	//注意收发两端文本要使用对应的编解码
	const QString recv_text = QString::fromUtf8(m_socket->readAll());
	if (ui.sendFileBtn->isEnabled()) {
		ui.receiveEt->append(recv_text);
	}
	else {
		if (recv_text == "FileHead Succ") {
			qDebug() << "get FileHead Succ--------------";
			sendData();
		}
		else if (recv_text=="FileRec Done") {
			m_file.close();
			ui.sendBtn->setEnabled(true);
			ui.selectBtn->setEnabled(true);
			ui.sendFileBtn->setEnabled(true);
		}
	}
}
void ServerProject::on_sendBtn_clicked() {
	if (!m_server->isListening())
		return;
	//将发送区文本发送给客户端
	const QByteArray send_data = ui.sendEt->toPlainText().toUtf8();
	//数据为空就返回
	if (send_data.isEmpty())
		return;
	m_socket->write(send_data);
	ui.sendEt->clear();
}
void ServerProject::on_clearRecBtn_clicked() {
	ui.receiveEt->clear();
}
void ServerProject::on_selectBtn_clicked() {
	QString filePath = QFileDialog::getOpenFileName(this, "open", "../");
	if (!filePath.isEmpty()) {
		//m_sendEnable = false;
		m_filename = "";
		m_fileSize = 0;
		m_sendSize = 0;
		QFileInfo info(filePath);
		m_filename = info.fileName();
		m_fileSize = info.size();
		qDebug() << "slectfile name: " << m_filename << " size: " << m_fileSize;
		m_file.setFileName(filePath);
		if (m_file.open(QIODevice::ReadOnly)) {
			//m_sendEnable = true;
			ui.selectBtn->setEnabled(false);
			ui.sendBtn->setEnabled(false);
			ui.sendFileBtn->setEnabled(true);
		}
	}
}
void ServerProject::on_sendFileBtn_clicked() {
	QString filehead = QString("%1#%2").arg(m_filename).arg(m_fileSize);
	qint64 len = m_socket->write(filehead.toUtf8());
	if (len > 0) {
		qDebug() << "filehead:  " << filehead;
		ui.sendFileBtn->setEnabled(false);
	}
}
void ServerProject::sendData() {
	qint64 len = 0;
	do {
		//一次发送的大小
		char buf[BUF_SIZE] = { 0 };
		len = 0;
		len = m_file.read(buf, BUF_SIZE);  //读取的字节数
		len = m_socket->write(buf, len);    //发送的字节数
		qDebug() << "len-----" << len;
		//已发数据累加
		m_sendSize += len;
	} while (len > 0);
}

服务端代码如下：

ClientPro::ClientPro(QWidget *parent)
    : QWidget(parent)
{
    ui.setupUi(this);
    initClient();
}
ClientPro::~ClientPro()
{
	qDebug() << "~ClientPro()----------------------------";
	if (m_client->state() == QAbstractSocket::ConnectedState) {
		//如果使用disconnectFromHost()不会重置套接字，isValid还是会为true
		m_client->abort();
	}
}
void ClientPro::initClient() {
	m_fileMaxsize = 100;
	m_sendEnable = false;
	//创建client对象
	m_client = new QTcpSocket(this);
}
void ClientPro::on_connectBtn_clicked() {
	if (m_client->state() == QAbstractSocket::ConnectedState) {
		//如果使用disconnectFromHost()不会重置套接字，isValid还是会为true
		m_client->abort();
	}
	else if (m_client->state() == QAbstractSocket::UnconnectedState) {
		//从界面上读取ip和端口
		const QHostAddress address = QHostAddress(ui.addressEt->text());
		const unsigned short port = ui.portEt->text().toUShort();
		//连接服务器
		m_client->connectToHost(address, port);
	}
	else {
		ui.receiveEt->append("It is not ConnectedState or UnconnectedState");
	}
	connect(m_client, &QTcpSocket::connected, this, &ClientPro::connectedSlot);
	connect(m_client, &QTcpSocket::disconnected, this, &ClientPro::disconnectedSlot);
	connect(m_client, &QTcpSocket::readyRead, this, &ClientPro::readyReadSlot);
}
void ClientPro::connectedSlot() {
	ui.connectBtn->setText("Disconnect");
	ui.addressEt->setEnabled(false);
	ui.portEt->setEnabled(false);
}
void ClientPro::disconnectedSlot() {
	ui.connectBtn->setText("Connect");
	ui.addressEt->setEnabled(true);
	ui.portEt->setEnabled(true);
}
void ClientPro::readyReadSlot() {
	if (m_client->bytesAvailable() <= 0)
		return;
	//注意收发两端文本要使用对应的编解码
	QByteArray buf = m_client->readAll();
	const QString recv_text = QString::fromUtf8(buf);

	QStringList list = recv_text.split("#");
	qDebug() << "listsize: " << list.size();
	if (!m_sendEnable&&list.size() == 2) {
		m_sendEnable = true;
		ui.sendBtn->setEnabled(false);
		m_recSize = 0;
		m_client->write("FileHead Succ");
		m_file.setFileName(list[0]);
		m_fileMaxsize = list[1].toInt();
		ui.progressBar->setValue(m_recSize);
		ui.progressBar->setMaximum(m_fileMaxsize);
		if (m_file.open(QIODevice::WriteOnly)) {
			return;
		}
	}
	if (!m_sendEnable) {
		ui.receiveEt->append(recv_text);
	}
	else {
		qint64 len = m_file.write(buf);
		m_recSize += len;
		qDebug() << "client----m_recSize: " << m_recSize;
		ui.progressBar->setValue(m_recSize);
		if (m_recSize == m_fileMaxsize) {
			qDebug() << "rec done--------------";
			m_sendEnable = false;
			m_file.close();
			m_client->write("FileRec Done");
			ui.sendBtn->setEnabled(true);
		}
	}
}
void ClientPro::on_sendBtn_clicked() {
	if (!m_client->isValid())
		return;
	//将发送区文本发送给客户端
	const QByteArray send_data = ui.sendEt->toPlainText().toUtf8();
	//数据为空就返回
	if (send_data.isEmpty())
		return;
	m_client->write(send_data);
}
void ClientPro::on_clearRecBtn_clicked() {
	ui.receiveEt->clear();
}
void ClientPro::on_clearSendBtn_clicked() {
	ui.sendEt->clear();
}

动态显示如下：