返回HashMap< String，Object>来自GraphQL-Java [英] Return HashMap<String, Object> from GraphQL-Java

问题描述

我尝试了几种变体，没有运气在GraphQL中返回地图.所以我有以下两个对象:

I tried few variant and had no luck to return a map in GraphQL. So I have the following two objects:

public class Customer {

    private String name, age;
    // getters & setters
}

public class Person {

   private String type;
   private Map<String, Customer> customers;
   // getters & setters
}

我的模式如下:

type Customer {
   name: String!
   age:  String!
}

type Person {
  type: String!
  customers: [Customer!] // Here I tried all combination but had no luck, is there a Map type support for GQL?
}

有人可以告诉我如何实现此目标，以便GraphQL神奇地处理此目标或替代方法.

Can someone please tell me how to achieve this so that GraphQL magically process this or an alternative approach.

非常感谢！

推荐答案

以防万一-您始终可以将地图对象表示为JSON字符串(对我来说是有帮助的).

Just in case - you can always represent map object as a JSON string (in my case it was helpful).

public class Person {

    private String type;
    private Map<String, Customer> customers;
    // getters & setters
}

将会

type Person {
  type: String!
  customers: String!
}

此后，别忘了添加数据提取程序以将其转换为JSON.

After that don't forget to add data fetcher to convert it to the JSON.

public DataFetcher<String> fetchCustomers() {
        return environment -> {
            Person person = environment.getSource();
            try {
                ObjectMapper objectMapper = new ObjectMapper();
                return objectMapper.writeValueAsString(person.getCustomers());
            } catch (JsonProcessingException e) {
                log.error("There was a problem fetching the person!");
                throw new RuntimeException(e);
            }
        };
    }

它将返回:

"person": {
    "type": "2",
    "customers": "{\"VIP\":{\"name\":\"John\",\"age\":\"19\"},\"Platinum VIP\":{\"name\":\"Peter\",\"age\":\"65\"}}"
  }

此后，您可以像处理客户端中的典型JSON字符串一样与客户进行合作.

After that, you can operate with customers as with typical JSON string in your client.

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