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
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