QTtcp socket协议如何发送文件

QTcpSocket协议可以通过以下步骤发送文件：

1. 打开文件并读取文件内容。

QFile file(filePath);
if (!file.open(QIODevice::ReadOnly)) {
    qWarning("Can't open file for reading");
    return;
}
QByteArray fileData = file.readAll();

2. 连接到服务器并发送文件大小。

QTcpSocket socket;
socket.connectToHost(host, port);
if (!socket.waitForConnected()) {
    qWarning("Can't connect to server");
    return;
}
qint64 fileSize = file.size();
socket.write(reinterpret_cast<const char*>(&fileSize), sizeof(fileSize));
socket.flush();

3. 等待服务器确认收到文件大小。

if (!socket.waitForReadyRead()) {
    qWarning("Did not receive confirmation from server");
    return;
}
qint64 bytesReceived = socket.read(sizeof(bytesReceived));
if (bytesReceived != sizeof(bytesReceived)) {
    qWarning("Did not receive confirmation from server");
    return;
}

4. 发送文件内容。

qint64 bytesWritten = 0;
while (bytesWritten < fileSize) {
    qint64 bytesToWrite = qMin(fileSize - bytesWritten, static_cast<qint64>(socket.bytesToWrite()));
    qint64 bytesActuallyWritten = socket.write(fileData.mid(bytesWritten, bytesToWrite));
    if (bytesActuallyWritten == -1) {
        qWarning("Error writing to server");
        return;
    }
    bytesWritten += bytesActuallyWritten;
}
socket.flush();

5. 等待服务器确认收到文件内容。

if (!socket.waitForBytesWritten()) {
    qWarning("Did not receive confirmation from server");
    return;
}
if (!socket.waitForReadyRead()) {
    qWarning("Did not receive confirmation from server");
    return;
}
qint64 bytesReceived = socket.read(sizeof(bytesReceived));
if (bytesReceived != sizeof(bytesReceived)) {
    qWarning("Did not receive confirmation from server");
    return;
}

6. 关闭连接。

socket.disconnectFromHost();

以上是一个简单的发送文件的示例，需要注意的是，如果文件较大，可能需要分段发送并且需要处理接收方的缓冲区溢出等问题。