Finally i got solution by referring documentaion
http://developer.blackberry.com/native/reference/cascades/qstring.html#details
STEP 1:
Declare this in cpp header #include <QStringList>
STEP 2:
JsonDataAccess jda;
QVariantMap map = jda.loadFromBuffer(reply->readAll()).toMap();
QVariantList addresses = map["RegistrationResult"].toList();
qDebug() << "RegistrationResult is "<<map["RegistrationResult"].toString();
QString result;
QString empid;
QString empid_no;
QString companyname;
QString::SectionFlag flag = QString::SectionSkipEmpty;
result=m_temperature.section(':', 0, 0);
empid=m_temperature.section(':', 1, 1);
empid_no=m_temperature.section(':', 2, 2);
companyname==m_temperature.section(':', 4, 4);