QT 获取文件MD5值

水深无声 2023-07-05 11:37 113阅读 0赞

/* 方法1 */
        QFile theFile(fileNamePath);
        theFile.open(QIODevice::ReadOnly);
        QByteArray ba = QCryptographicHash::hash(theFile.readAll(), QCryptographicHash::Md5);
        theFile.close();
        qDebug() << ba.toHex().constData();

/* 方法2 */
    /*
    *   获取文件md5值
    */
    QByteArray MainWindow::getFileMd5(QString filePath)
    {
        QFile localFile(filePath);
     
        if (!localFile.open(QFile::ReadOnly))
        {
            qDebug() << "file open error.";
            return 0;
        }
     
        QCryptographicHash ch(QCryptographicHash::Md5);
     
        quint64 totalBytes = 0;
        quint64 bytesWritten = 0;
        quint64 bytesToWrite = 0;
        quint64 loadSize = 1024 * 4;
        QByteArray buf;
     
        totalBytes = localFile.size();
        bytesToWrite = totalBytes;
     
        while (1)
        {
            if(bytesToWrite > 0)
            {
                buf = localFile.read(qMin(bytesToWrite, loadSize));
                ch.addData(buf);
                bytesWritten += buf.length();
                bytesToWrite -= buf.length();
                buf.resize(0);
            }
            else
            {
                break;
            }
     
            if(bytesWritten == totalBytes)
            {
                break;
            }
        }
     
        localFile.close();
        QByteArray md5 = ch.result();
     
        return md5;
    }

# Qt 计算文件（含超大文件）的 md5 值  #

//大文件MD5
    QString fileMd5(const QString &sourceFilePath) {
    
        QFile sourceFile(sourceFilePath);
        qint64 fileSize = sourceFile.size();
        const qint64 bufferSize = 10240;
    
        if (sourceFile.open(QIODevice::ReadOnly)) {
            char buffer[bufferSize];
            int bytesRead;
            int readSize = qMin(fileSize, bufferSize);
    
            QCryptographicHash hash(QCryptographicHash::Md5);
    
            while (readSize > 0 && (bytesRead = sourceFile.read(buffer, readSize)) > 0) {
                fileSize -= bytesRead;
                hash.addData(buffer, bytesRead);
                readSize = qMin(fileSize, bufferSize);
            }
    
            sourceFile.close();
            return QString(hash.result().toHex());
        }
        return QString();
    }

包含测试的完整代码如下：

#include <QCoreApplication>
    #include <QCryptographicHash>
    #include <QFile>
    #include <QDebug>
    
    QString fileMd5(const QString &sourceFilePath) {
    
        QFile sourceFile(sourceFilePath);
        qint64 fileSize = sourceFile.size();
        const qint64 bufferSize = 10240;
    
        if (sourceFile.open(QIODevice::ReadOnly)) {
            char buffer[bufferSize];
            int bytesRead;
            int readSize = qMin(fileSize, bufferSize);
    
            QCryptographicHash hash(QCryptographicHash::Md5);
    
            while (readSize > 0 && (bytesRead = sourceFile.read(buffer, readSize)) > 0) {
                fileSize -= bytesRead;
                hash.addData(buffer, bytesRead);
                readSize = qMin(fileSize, bufferSize);
            }
    
            sourceFile.close();
            return QString(hash.result().toHex());
        }
        return QString();
    }
    
    int main(int argc, char *argv[])
    {
        QCoreApplication a(argc, argv);
    
        QString md5("0e40d388359b41334831b898262cfe93"); // 使用 md5sum 命令获取
    
        QString result = fileMd5("/home/toby/bin/Tools.zip");
        qDebug() << "source MD5: " << md5;
        qDebug() << "result MD5: " << result;
        qDebug() << "is equal: " << (result == md5);
        return a.exec();
    }

使用 10.1 GB 超大文件的进行测试

![format_png][]

10.1 GB 超大文件

测试结果如下：

![format_png 1][]

参考：[https://blog.csdn.net/u010780613/article/details/52242846][https_blog.csdn.net_u010780613_article_details_52242846]

[format_png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly91cGxvYWQtaW1hZ2VzLmppYW5zaHUuaW8vdXBsb2FkX2ltYWdlcy80MDExMDc4LTk1ZmQ2MjgzMjk4MjU1MDEucG5nP2ltYWdlTW9ncjIvYXV0by1vcmllbnQvc3RyaXB8aW1hZ2VWaWV3Mi8yL3cvNDYyL2Zvcm1hdC93ZWJw?x-oss-process=image/format,png
[format_png 1]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly91cGxvYWQtaW1hZ2VzLmppYW5zaHUuaW8vdXBsb2FkX2ltYWdlcy80MDExMDc4LWNjYTY0ZjllNGU3MTYyMTEucG5nP2ltYWdlTW9ncjIvYXV0by1vcmllbnQvc3RyaXB8aW1hZ2VWaWV3Mi8yL3cvMTAyMS9mb3JtYXQvd2VicA?x-oss-process=image/format,png
[https_blog.csdn.net_u010780613_article_details_52242846]: https://blog.csdn.net/u010780613/article/details/52242846