下面的示例对我很有用

static class PersonData {
    int age;
    String surname;
    public String toString() {
        return "[age = " + age + ", surname = " + surname + "]";
    }
}

public static void main(String[] args) {
    String json = "{\"Thomas\": {\"age\": 32,\"surname\": \"Scott\"},\"Andy\": {\"age\": 25,\"surname\": \"Miller\"}}";
    System.out.println(json);
    Gson gson = new Gson();
    Map<String, PersonData> decoded = gson.fromJson(json, new TypeToken<Map<String, PersonData>>(){}.getType());
    System.out.println(decoded);
}

字符串
并打印

{"Thomas": {"age": 32,"surname": "Scott"},"Andy": {"age": 25,"surname": "Miller"}}
{Thomas=[age = 32, surname = Scott], Andy=[age = 25, surname = Miller]}

型
你的PersonData类可能非常不同。

您可以使用gson.toJsonTree(Object o)将自定义对象转换为JSON格式。
以下是我的工作：

private static class PersonData {
    private int age;
    private String surname;

    public PersonData(int age, String surname) {
        this.age = age;
        this.surname = surname;
    }
}

public static void main(String[] args) {
    PersonData first = new PersonData(24, "Yovkov");
    PersonData second = new PersonData(25, "Vitanov");

    Gson gson = new Gson();

    JsonObject jsonObject = new JsonObject();
    jsonObject.add("kocko", gson.toJsonTree(first));
    jsonObject.add("deyan", gson.toJsonTree(second));

    System.out.println(gson.toJson(jsonObject));

}

字符串
并打印：

{"kocko":{"age":24,"surname":"Yovkov"},"deyan":{"age":25,"surname":"Vitanov"}}

型