火爆外网的 DGS 框架使用

Netflix 已开放其 Domain Graph Service（DGS）框架的源代码，该框架是为了方便整合 GraphQL 使用，用于简化 GraphQL 的实现。

GraphQL 主要是作用于数据接口，比如前端后端交互。无需定义或修改后台 Controller、Service 等业务代码即可实现灵活的数据变更，客户端可以自由获取服务端事先定义好的数据，提高了交互接口的灵活性

组件依赖

graphql-dgs-spring-boot-starter

<dependency>

    <groupId>com.netflix.graphql.dgs</groupId>

    <artifactId>graphql-dgs-spring-boot-starter</artifactId>

    <version>3.5.1</version>

</dependency>

DGS 必须从 jcenter 下载,不然部分依赖无法下载。踩坑很久

	<profiles>

		<profile>

			<activation>

				<activeByDefault>true</activeByDefault>

			</activation>

			<repositories>

				<repository>

					<snapshots>

						<enabled>false</enabled>

					</snapshots>

					<id>central</id>

					<name>bintray</name>

					<url>https://jcenter.bintray.com</url>

				</repository>

			</repositories>

			<pluginRepositories>

				<pluginRepository>

					<snapshots>

						<enabled>false</enabled>

					</snapshots>

					<id>central</id>

					<name>bintray-plugins</name>

					<url>https://jcenter.bintray.com</url>

				</pluginRepository>

			</pluginRepositories>

			<id>bintray</id>

		</profile>

	</profiles>

定义接口 schema

/src/main/resources/schema/schema.graphqls

此文件定义了客户端请求入参格式和查询数据类型

type Query {

    shows(title: String ,releaseYear: Int): [Show]

}

type Show {

    title: String

    releaseYear: Int

}

定义数据抽取规则

@DgsComponent

public class ShowsDatafetcher {

	@DgsData(parentType = "Query", field = "shows")

	public List<Show> shows(@InputArgument("title") String title, @InputArgument("releaseYear") Integer releaseYear) {

		if (title == null) {

			return shows;

		}

		return shows.stream().filter(s -> s.getTitle().contains(title)).collect(Collectors.toList());

	}

    // 模拟 DB 查询

  	private final List<Show> shows = List.of(

			new Show("java", 1995),

			new Show("php", 1995),

			new Show("python", 1990),

			new Show("golang", 2009),

			new Show("rust", 2015)

	);

}

UI 前端调试

访问: http://localhost:8080/graphiql

条件查询

接口调用

curl --location --request POST 'http://localhost:8080/graphql' \

--header 'Content-Type: application/json' \

--data-raw '{"query":"{\n  shows(title: \"java\", releaseYear: 1995) {\n    title\n    releaseYear\n  }\n}\n","variables":null}'

java 调用

@SpringBootTest(classes = {DgsAutoConfiguration.class, ShowsDatafetcher.class})

class ShowsDatafetcherTests {

	@Autowired

	DgsQueryExecutor dgsQueryExecutor;

	@Test

	void shows() {

		List<String> titles = dgsQueryExecutor.executeAndExtractJsonPath(

				" { shows { title releaseYear }}",

				"data.shows[*].title");

		assertThat(titles).contains("java");

	}

}

本节源码

源码: https://github.com/lltx/dgs-demo

DGS 官网: https://netflix.github.io/dgs

>>> 源码 https://gitee.com/log4j/pig，欢迎署名转载 <<<

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