转载自json c++ examples

// ---- create from scratch ----

Json::Value fromScratch;
Json::Value array;
array.append("hello");
array.append("world");
fromScratch["hello"] = "world";
fromScratch["number"] = 2;
fromScratch["array"] = array;
fromScratch["object"]["hello"] = "world";

output(fromScratch);

// write in a nice readible way
Json::StyledWriter styledWriter;
std::cout << styledWriter.write(fromScratch);

// ---- parse from string ----

// write in a compact way
Json::FastWriter fastWriter;
std::string jsonMessage = fastWriter.write(fromScratch);

Json::Value parsedFromString;
Json::Reader reader;
bool parsingSuccessful = reader.parse(jsonMessage,parsedFromString);
if (parsingSuccessful)
{
    std::cout << styledWriter.write(parsedFromString) << std::endl;
}

void output(const Json::Value & value)
{
    // querying the json object is very simple
    std::cout << value["hello"];
    std::cout << value["number"];
    std::cout << value["array"][0] << value["array"][1];
    std::cout << value["object"]["hello"];
}