qt TCP客户端判断服务端关闭连接

一、客户端判断服务端是不是已经关闭的简单方法就是发送发送数据，看返回是不是有错误

二、客户端建立连接

void MainWindow::btn_connect_server()
{
    m_tcpClient=new QTcpSocket(this);

   connect(m_tcpClient,SIGNAL(connected()),this,SLOT(connected_success()));

   connect(m_tcpClient,SIGNAL(readyRead()),this,SLOT(updateReadServerProgress()));

   m_tcpClient->connectToHost("192.168.2.228",10086);
}
void MainWindow::connected_success(){

    ui->plainTextEdit->appendPlainText("连接服务器成功");
}

二、判断部分

void MainWindow::btn_server_is_online()
{
   qint64 x = m_tcpClient->write("aaaa");

   if(x ==-1)
   {
      ui->plainTextEdit->appendPlainText("关闭连接");
   }
   else
   {
        ui->plainTextEdit->appendPlainText("正常连接");
   }
}

三、在服务器关闭连接

    m_tcpServerConnection->close();
    ui->textEdit->setPlainText("服务器关闭！");