GraphQL Spring Boot 客户端：处理对象列表的完整指南

type Person {
  firstName: String
  middleName: String
  lastName: String
  birthDt: String
}

type Query {
  getPersonsByIds(personIds: [String]): [Person]
}

import com.fasterxml.jackson.databind.ObjectMapper;
import com.github.americanexpress.graphql.spring.GraphQLTemplate;
import com.github.americanexpress.graphql.spring.operations.GraphQLRequestEntity;
import org.springframework.stereotype.Service;

import java.net.MalformedURLException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Service
public class PersonService {

    private final GraphQLTemplate graphQLTemplate = new GraphQLTemplate();
    private final String url = "http://localhost:8084/graphql";

    public List<Person> getPersonsByIds(List<String> personIds) {

        GraphQLRequestEntity requestEntity;
        try {
            // 使用 Jackson ObjectMapper 构建变量
            ObjectMapper mapper = new ObjectMapper();
            Map<String, Object> variables = new HashMap<>();
            variables.put("personIds", personIds);

            requestEntity = GraphQLRequestEntity.Builder()
                .url(url)
                .requestMethod(GraphQLTemplate.GraphQLMethod.QUERY)
                .request("query($personIds: [String]) {\n" +
                    "  getPersonsByIds(personIds : $personIds ) {\n" +
                    "    firstName\n" +
                    "    middleName\n" +
                    "    lastName\n" +
                    "    birthDt\n" +
                    "  }\n" +
                    "}"
                )
                // 使用 Map 传递变量
                .variables(variables)
                .build();
        } catch (MalformedURLException e) {
            throw new RuntimeException(e);
        }
        // 假设 ResponseGetPersonsByIds 包含一个 getGetPersonsByIds() 方法
        return graphQLTemplate.query(requestEntity, ResponseGetPersonsByIds.class).getResponse().getGetPersonsByIds();
    }

    // 内部类，用于模拟响应结构
    private static class ResponseGetPersonsByIds {
        private List<Person> getPersonsByIds;

        public List<Person> getGetPersonsByIds() {
            return getPersonsByIds;
        }

        public void setGetPersonsByIds(List<Person> getPersonsByIds) {
            this.getPersonsByIds = getPersonsByIds;
        }
    }

    // 内部类，用于模拟 Person 对象
    public static class Person {
        private String firstName;
        private String middleName;
        private String lastName;
        private String birthDt;

        // Getters and setters
        public String getFirstName() {
            return firstName;
        }

        public void setFirstName(String firstName) {
            this.firstName = firstName;
        }

        public String getMiddleName() {
            return middleName;
        }

        public void setMiddleName(String middleName) {
            this.middleName = middleName;
        }

        public String getLastName() {
            return lastName;
        }

        public void setLastName(String lastName) {
            this.lastName = lastName;
        }

        public String getBirthDt() {
            return birthDt;
        }

        public void setBirthDt(String birthDt) {
            this.birthDt = birthDt;
        }
    }

    public static void main(String[] args) {
        PersonService personService = new PersonService();
        List<String> ids = Arrays.asList("2477142261427744786", "2477142261427744787");
        List<Person> persons = personService.getPersonsByIds(ids);

        if (persons != null) {
            persons.forEach(person -> System.out.println(person.getFirstName()));
        } else {
            System.out.println("No persons found.");
        }
    }
}