字符串按照“=”分割，c++

string EventTrigger::SegmentationString(std::string& str) {
try {
string dft_val;
const std::string& seprator = "=";
std::vector<std::string> vec;
StringUtils::SplitStrToVec(str, seprator.c_str(), vec);
if (vec.size() == 2)
{
dft_val = StringUtils::StringToFloat(vec[1]);
}
return dft_val;
}
catch (...) {
return NULL;
}
}