nlohmann's json library convert an array to a vector of structs

问题

Say I have a json array that looks like this:

[
  {
    "Name": "test",
    "Val": "test_val"
  },
  {
    "Name": "test2",
    "Val": "test_val2"
  }
]

I want to convert this into a vector of structs:

struct Test {
  string Name;
  string Val;
};

I know about the json.get<>() method, but do not know how to apply that to this.

回答1:

For the automatic get<> to work, you need to provide a mapping between JSON and your struct:

void from_json(const nlohmann::json& j, Test& p) {
    j.at("Name").get_to(p.Name);
    j.at("Val").get_to(p.Val);
}

Then it will work as expected.

auto parsed = json.get<std::vector<Test>>();

Demo: https://godbolt.org/z/9P1mjO

来源：https://stackoverflow.com/questions/60325894/nlohmanns-json-library-convert-an-array-to-a-vector-of-structs