如何从Java应用程序调用GraphQL端点

我正在尝试调用外部GraphQL端点，而不是由我控制，我在internet上所能找到的只是如何使用JavaSpringBoot设置后端GraphQL端点。如何从Java应用程序调用GraphQL端点？

Netflix DGS有springboot客户端库

参考：

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我想您只是将查询作为文本发送到端点。感谢您的分享，当我添加graphql dgs spring boot starter此依赖项，然后尝试创建DefaultGraphQLClient的实例时，它表示无法解析符号。你能帮我解决我这里缺少的问题吗？将com.netflix.graphql.dgs:graphql-dgs-spring-boot-starter依赖项添加到Gradle或Maven配置中，并像导入任何其他java一样导入该类。参考号：。如果您能将上述内容标记为有用，并且选择正确的选项作为正确答案，我将不胜感激。现在，我收到了以下错误：“创建名为“schema”的bean时出错，该bean在类路径资源[com/netflix/graphql/dgs/autoconfig/DgsAutoConfiguration.class]：创建bean时出现意外异常；嵌套异常为java.lang.TypeNotPresentException:Type graphql.schema.GraphQLCodeRegistry not Presentation不存在“”。这在几分钟前还有效…现在我开始出现这个错误

private RestTemplate dgsRestTemplate;

private static final String URL = "http://someserver/graphql";

private static final String QUERY = "{\n" +
            "  ticks(first: %d, after:%d){\n" +
            "    edges {\n" +
            "      node {\n" +
            "        route {\n" +
            "          name\n" +
            "          grade\n" +
            "          pitches\n" +
            "          location\n" +
            "        }\n" +
            "        \n" +
            "        userStars\n" +
            "      }\n" +
            "    }\n" +
            "  }\n" +
            "}";

public List<TicksConnection> getData() {
    DefaultGraphQLClient graphQLClient = new DefaultGraphQLClient(URL);
    GraphQLResponse response = graphQLClient.executeQuery(query, new HashMap<>(), (url, headers, body) -> {
        /**
         * The requestHeaders providers headers typically required to call a GraphQL endpoint, including the Accept and Content-Type headers.
         * To use RestTemplate, the requestHeaders need to be transformed into Spring's HttpHeaders.
         */
        HttpHeaders requestHeaders = new HttpHeaders();
        headers.forEach(requestHeaders::put);

        /**
         * Use RestTemplate to call the GraphQL service. 
         * The response type should simply be String, because the parsing will be done by the GraphQLClient.
         */
        ResponseEntity<String> exchange = dgsRestTemplate.exchange(url, HttpMethod.POST, new HttpEntity(body, requestHeaders), String.class);

        /**
         * Return a HttpResponse, which contains the HTTP status code and response body (as a String).
         * The way to get these depend on the HTTP client.
         */
        return new HttpResponse(exchange.getStatusCodeValue(), exchange.getBody());
    }); 

    TicksConnection ticks = graphQLResponse.extractValueAsObject("ticks", TicksConnection.class);
    return ticks;
}