本文主要是介绍QT QProcess的使用2，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
定义
The QProcess class is used to start external programs and to communicate with them.
QProcess类是用来启动一个外部程序并与之通信。
使用说明
开启外部线程的3中方式
To start a process, pass the name and command line arguments of the program you want to run as arguments to start(). Arguments are supplied as individual strings in a QStringList.
Alternatively, you can set the program to run with setProgram() and setArguments(), and then call start() or open().
想要启动一个进程，可以传递你想启动的程序的名字和命令行参数作为参数传递给start()函数。参数作为QStringList中每一个单独的字符串。
或者，你可以通过setProgram()和setArguments()来设置该程序，然后调用start()或者open()启动该程序。
启动时在指定程序名时就附带上参数
QProcess process;
process.start("cmd /c ping 127.0.0.1");启动时分别指定函数名和参数列表
QProcess process;
process.start("cmd", QStringList()<<"/c"<<"ping 127.0.0.1", QIODevice::ReadWrite);分别指定函数名和参数，然后再启动
QProcess process;
process.setProgram("cmd");
process.setArguments(QStringList()<<"/c"<<"ping 127.0.0.1");
process.start(QIODevice::ReadWrite);一次性读取进程输出
void readProcessAllOnce(bool processAutoExit) {qDebug()<<"readProcessAllOnce, processAutoExit ="<<processAutoExit;qDebug()<<"----------------------";bool ret;QProcess process;QString command;if(processAutoExit) {command = "cmd /c ping 127.0.0.1";} else {command = "cmd /k ping 127.0.0.1";}process.start(command);/** bool QProcess::waitForStarted(int msecs = 30000)*/ret = process.waitForStarted();qDebug()<<"waitForStarted"<<ret;qDebug()<<QDateTime::currentDateTime();/** 如果打开的不是自动关闭的进程，那么这里最多可能会等待30秒* bool QProcess::waitForFinished(int msecs = 30000)*/ret = process.waitForFinished();qDebug()<<QDateTime::currentDateTime();qDebug()<<"waitForFinished"<<ret;QByteArray byteArray = process.readAllStandardOutput();QString str = QString::fromLocal8Bit(byteArray);qDebug()<<str;process.close();qDebug()<<"";qDebug()<<"======================";
}
按行读取进程输出
void readProcessByLine() {qDebug()<<"readProcessByLine";qDebug()<<"----------------------";bool ret;QProcess process(0);/** cmd /c 的命令执行完后会关闭窗口* cmd /k 的命令执行完后不会关闭窗口** aa && bb 就是执行aa，成功后再执行bb* aa || bb 先执行aa，若执行成功则不再执行bb，若失败则执行bb* a & b 表示执行a再执行b，而无论a是否成功*/process.start("cmd", QStringList()<<"/k"<<"ping 127.0.0.1"<<"&"<<"exit", QIODevice::ReadWrite);
// process.setProgram("cmd");
// process.setArguments(QStringList()<<"/k"<<"ping 127.0.0.1"<<"&"<<"exit");
// process.start(QIODevice::ReadWrite);ret = process.waitForStarted();qDebug()<<"waitForStarted"<<ret;qint64 maxSize = 512;char buffer[maxSize];qint64 len;while(true) {/** 一个waitForReadyRead信号可能输出的是多行*/ret = process.waitForReadyRead();qDebug()<<"waitForReadyRead"<<ret;if(!ret) {break;}while(true) {len = process.readLine(buffer, maxSize);qDebug()<<"buffer len"<<len;/** 因为每一行至少还有回车换行符，因此读到0，说明waitForReadyRead超时返回false*/if(len <= 0) {break;}QString str = QString::fromLocal8Bit(buffer);qDebug()<<"qstring len"<<str.length();qDebug()<<str;qDebug()<<"";}}process.write("exit\r\n");ret = process.waitForFinished();qDebug()<<"waitForFinished"<<ret;process.close();qDebug()<<"";qDebug()<<"======================";
}
与进程交互
void openProcessThenWrite() {qDebug()<<"openProcessThenWrite";qDebug()<<"----------------------";bool ret;QProcess *process = new QProcess(QThread::currentThread());/** 如果没有QCoreApplication的话，会报如下错误* QObject::startTimer: Timers can only be used with threads started with QThread. timer只能在同一个线程中创建和启动.*/process->start("cmd", QIODevice::ReadWrite);ret = process->waitForStarted();qDebug()<<"waitForReadyRead"<<ret;QByteArray byteArray = process->readAllStandardOutput();QString str = QString::fromLocal8Bit(byteArray);qDebug()<<str;//这里不加换行的话命令发不出去qint64 len = process->write("ping 127.0.0.1\r\nexit\r\n");qDebug()<<"write len"<<len;while(true) {/** 如果进程已经关闭，waitForReadyRead会直接返回false*/ret = process->waitForReadyRead();qDebug()<<"waitForReadyRead"<<ret;if(!ret) {break;}byteArray = process->readAllStandardOutput();str = QString::fromLocal8Bit(byteArray);qDebug()<<str;qDebug()<<"";}/** 如果没有关闭cmd的指令，因此该process永远不会finished，会超时(30秒)返回false*/ret = process->waitForFinished();qDebug()<<"waitForFinished"<<ret;process->close();delete process;qDebug()<<"";qDebug()<<"======================";
}
测试函数
#include <QCoreApplication>
#include <QDebug>
#include <QProcess>
#include <QThread>
#include <QDateTime>void readProcessAllOnce(bool processAutoExit) {……
}void readProcessByLine() {……
}void openProcessThenWrite() {……
}int main(int argc, char *argv[])
{QCoreApplication a(argc, argv);qDebug()<<"======================";readProcessAllOnce(false);readProcessAllOnce(true);readProcessByLine();openProcessThenWrite();qDebug()<<"That's all";return a.exec();
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