1.通过find进行检查

#include <iostream>
#include <nlohmann/json.hpp>
using namespace std;
using json = nlohmann::json;int main()
{json data = R"({"name": "xiaoming","age": 10, "parent":   [{"father" : "zhang","age" : 40},{"mother" : "wang","age" : 36}]})"_json;auto ifFind = data.find("name");if(ifFind != data.end()){cout<<"name="<<data["name"]<<endl;}else{cout<<"name not exist"<<endl;}ifFind = data.find("address");if(ifFind != data.end()){cout<<