nlohmann 的 json 库将数组转换为结构向量

Question

Say I have a json array that looks like this:假设我有一个如下所示的 json 数组：

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

I want to convert this into a vector of structs:我想将其转换为结构向量：

struct Test {
  string Name;
  string Val;
};

I know about the json.get<>() method, but do not know how to apply that to this.我知道json.get<>()方法，但不知道如何将其应用于此。

Answer 1

For the automatic get<> to work, you need to provide a mapping between JSON and your struct:要使自动get<>工作，您需要提供 JSON 和结构之间的映射：

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.然后它将按预期工作。

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