使用QCryptographicHash对文件进行MD5计算。用来检测文件是否改变

来源：互联网发布：用友代理记账软件编辑：程序博客网时间：2024/06/05 15:41

占个坑，有空写。先把代码传上来。

#include "c4hashcrypt.h"#include <QFile>#include <QTextCodec>#include <QTextStream>#include <QCryptographicHash>#include <QDebug>/*********************************************************** * 遍历大文件16g大概2分多，如果是零碎文件5g大概6分钟 * ********************************************************/C4HashCrypt::C4HashCrypt(QObject *parent) :    QObject(parent){}bool C4HashCrypt::md5Files(QStringList fileList, QString hashFile){    QFile hM5file(hashFile);    QString lastest("Desktop/");    if(hM5file.open(QFile::Truncate|QFile::WriteOnly|QFile::Text))    {        foreach (QString file, fileList) {             QByteArray bb = md5file(file);             bb.append("    [file]= ");             file =file.right(file.size()-file.lastIndexOf(lastest));//去掉指定文件路径~             file = file.right(file.size()-QString(lastest).size());             bb.append(file);             bb.append('\n');             hM5file.write(bb);        }        hM5file.close();        return true;    }    else    {        qDebug()<<"openHM5file False";        return false;    }}QByteArray C4HashCrypt::md5file(QString fileName){    QByteArray md5C = Q_NULLPTR;    QFile file(fileName);   // QTextCodec  *code = QTextCodec::codecForName("utf8");    if(file.exists())    {        if(file.open(QFile::ReadOnly))        {#if 0            QTextStream  stream(&file);//如果用这种方法则会导致加密rar文件报错。            stream.setCodec(code);            QString data;            data = stream.readAll();            md5C = QCryptographicHash::hash(data.toLatin1(),\                                            QCryptographicHash::Md5).toHex();//必须有.toHex();#else            QCryptographicHash hash(QCryptographicHash::Md5);            hash.addData(&file);            md5C = hash.result().toHex();#endif            file.close();        }else        {            qDebug()<<"open file False";        }    }else    {        qDebug()<<"file is not exit";    }    return md5C;}

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