GraphQL on F嘉阳

GraphQL实践10——Netflix Dgs Graphql异步订阅

Fri, 28 Oct 2022 21:59:23 +0800

介绍

GraphQL订阅模式支持服务端主动向客户端推送数据通知，避免客户端轮训

DGS Subscriptions

新增依赖

此处使用的是SpringBoot Web组件，故引入websockets依赖

如果使用的是WebFlux则要引入对应的dgs-webflux

		 <dependency>
 <groupId>com.netflix.graphql.dgs</groupId>
 <artifactId>graphql-dgs-subscriptions-websockets-autoconfigure</artifactId>
 </dependency>

异步通知解析

此处定义为当新增一个Actor就给所有订阅者发异步通知

@Slf4j
@DgsComponent
@RequiredArgsConstructor
public class ActorDataFetcher {

	private final ActorAssembler actorAssembler;

	private FluxSink<Actor> actorStream;

	private ConnectableFlux<Actor> actorPublisher;

	@PostConstruct
	private void createActorPublisher() {
		Flux<Actor> publisher = Flux.create(emitter -> {
			actorStream = emitter;
		});

		actorPublisher = publisher.publish();
		actorPublisher.connect();
	}

	@DgsMutation
	public Actor addActor(@InputArgument SubmitActor actor) {
		Actor actorEntity = actorAssembler.convert(actor);
		actorEntity.setActorId(10);
		actorEntity.setLastUpdate(DateUtil.format(new Date(), DatePattern.NORM_DATETIME_PATTERN));
		actorStream.next(actorEntity);
		log.info("服务端创建演员：{}", actor);
		return actorEntity;
	}

	/**
	 * 异步通知
	 *
	 * @return
	 */
	@DgsSubscription
	public Publisher<Actor> actorAdded() {
		return actorPublisher;
	}
}

单元测试

由于异步通知无法用浏览器自带的控制台测试，只能通过GraphQL客户端订阅后接收异步通知，此处参考官方最佳实践，使用单元测试模拟

@Slf4j
@SpringBootTest
class ActorDataFetcherTest {

	@Autowired
	private DgsQueryExecutor dgsQueryExecutor;

	@Test
	void addActor() {

		GraphQLQueryRequest graphQLQueryRequest = new GraphQLQueryRequest(
				AddActorGraphQLQuery.newRequest()
						.actor(
								SubmitActor.newBuilder()
										.firstName("fu")
										.lastName("jiayang")
										.build())
						.build(),
				new AddActorProjectionRoot()
						.actorId()
						.firstName()
						.lastUpdate());
		dgsQueryExecutor.execute(graphQLQueryRequest.serialize());
	}

	@Test
	void actorAdded() {
		ExecutionResult executionResult = dgsQueryExecutor.execute("""
				subscription {
				 actorAdded {
				 actorId
				 firstName
				 lastName
				 lastUpdate
				 }
				}
				""");
		Publisher<ExecutionResult> reviewPublisher = executionResult.getData();
		List<Actor> actors = new CopyOnWriteArrayList<>();

		reviewPublisher.subscribe(new Subscriber<>() {
			@Override
			public void onSubscribe(Subscription s) {
				s.request(2);
			}

			@Override
			public void onNext(ExecutionResult executionResult) {
				if (executionResult.getErrors().size() > 0) {
					executionResult.getErrors().forEach(error -> log.error(error.toString()));
				}
				Map<String, Object> actorResult = executionResult.getData();
				Actor actor = new ObjectMapper().convertValue(actorResult.get("actorAdded"), Actor.class);
 log.info("客户端监听到演员新增：{}",actor);
				actors.add(actor);
			}

			@Override
			public void onError(Throwable t) {
				t.printStackTrace();
			}

			@Override
			public void onComplete() {
			}
		});

		addActor();
		addActor();

		assertThat(actors.size()).isEqualTo(2);
	}
}

从日志输出可以看到客户端成功接收异步通知

总结

订阅模式属于GraphQL特色功能，类似消息队列实现方式，减少客户端对普通查询接口轮训性能开销

GraphQL实践9——Netflix Dgs Graphql数据更新

Fri, 28 Oct 2022 21:58:54 +0800

功能介绍

graphql-java提供了Mutations类型支持数据更新

NGS Mutations

类型定义

type Mutation {
 addActor(actor: SubmitActor!): Actor
}

type Subscription {
 actorAdded: Actor
}

input SubmitActor {
 firstName: String!
 lastName: String!
}

SubmitActor类型可以交给代码生成器自动生成

类型转换器

@Mapper(componentModel = SPRING)
public interface ActorAssembler {

	Actor convert(SubmitActor submit);
}

定义解析器

	@DgsMutation
	public Actor addActor(@InputArgument SubmitActor actor) {
		Actor actorEntity = actorAssembler.convert(actor);
		actorEntity.setActorId(10);
		actorEntity.setLastUpdate(new Date());
		return actorEntity;
	}

测试

访问http://localhost:8080/graphiql即可看到在线查询页面

GraphQL实践8——Netflix Dgs Graphql代码生成

Fri, 28 Oct 2022 21:57:00 +0800

功能介绍

DGS官方开发了识别schema配置生成对应类型、测试类的代码生成器，而Maven插件则由社区维护

Maven代码生成插件

新增依赖

<dependency> 
 <groupId>com.netflix.graphql.dgs.codegen</groupId> 
 <artifactId>graphql-dgs-codegen-client-core</artifactId> 
 <version>5.1.17</version> 
</dependency>

还需要新增构建插件

	 <plugin>
 <groupId>io.github.deweyjose</groupId>
 <artifactId>graphqlcodegen-maven-plugin</artifactId>
 <version>1.24</version>
 <executions>
 <execution>
 <goals>
 <goal>generate</goal>
 </goals>
 </execution>
 </executions>
 <configuration>
 <addGeneratedAnnotation>true</addGeneratedAnnotation>
 <packageName>top.fjy8018.graphsqldemo.generated</packageName>
 <schemaPaths>
 <param>src/main/resources/graphql/actor.graphqls</param>
 </schemaPaths>
 <!-- 生成测试客户端 -->
 <generateClient>true</generateClient>
 </configuration>
 </plugin>
 <plugin>
 <groupId>org.codehaus.mojo</groupId>
 <artifactId>build-helper-maven-plugin</artifactId>
 <executions>
 <execution>
 <phase>generate-sources</phase>
 <goals>
 <goal>add-source</goal>
 </goals>
 <configuration>
 <sources>
 <source>${project.build.directory}/generated-sources</source>
 </sources>
 </configuration>
 </execution>
 </executions>
 </plugin>

插件配置指引：deweyjose/graphqlcodegen: Maven port of the Netflix Gradle code generation plugin for graphql.

编译

执行

mvn clean package

即可生成对应的类

存在问题

IDEA默认不识别target目录下的资源文件，生成后会导致无法引用

解决方法

需要手动将对应的生成目录配置为Source Root即可

总结

DGS官方推荐开发者优先使用代码生成器生成标准类库后再开发，可以减少开发量

GraphQL实践7——Netflix Dgs Graphql分页查询

Fri, 28 Oct 2022 16:06:31 +0800

问题背景

上一篇文章提到，使用List查询每次都返回全量数据，而实际场景更多使用分页查询，graphql-java提供Connection实现游标分页，在Dgs也有对应功能扩展Relay Pagination

集成Relay Pagination

新增依赖

 <dependency>
 <groupId>com.netflix.graphql.dgs</groupId>
 <artifactId>graphql-dgs-pagination</artifactId>
 </dependency>

Mybatis Plus 配置分页插件

@Configuration
@MapperScan("top.fjy8018.graphsqldemo.mapper")
public class MybatisPlusConfig {

 /**
 * 分页插件配置
 *
 * @return
 */
 @Bean
 public MybatisPlusInterceptor mybatisPlusInterceptor() {
 MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
 PaginationInnerInterceptor pageConfig = new PaginationInnerInterceptor(DbType.MYSQL);
 interceptor.addInnerInterceptor(pageConfig);
 return interceptor;
 }
}

Relay Pagination配置

type Query {
 actorList: [Actor]
 findOneActor(id : Int!): Actor
 filmList(current: Int!,size: Int!): FilmConnection
 findOneFilm(id : Int!): Film
}

type Actor {
 actorId: Int!
 firstName: String!
 lastName: String!
 lastUpdate: String
}

type Film @connection {
 filmId: Int!
 title: String!
 description: String
 releaseYear: Int
 languageId: Int!
 originalLanguageId: Int
 rentalDuration: Int
 rentalRate: Float
 length: Int
 replacementCost: Float
 rating: String
 specialFeatures: String
 lastUpdate: String
 actors: [Actor]
}

@connection和XXXConection已经由graphql-java底层框架自动生成，无需手动定义

类型转换器

public interface ConnectionAssembler {

 /**
 * mybatis plus分页对象转为Connection
 *
 * @param page 分页对象
 * @param <T> 泛型
 * @return Connection
 */
 static <T> Connection<T> convert(IPage<T> page) {
 AtomicInteger index = new AtomicInteger();
 List<Edge<T>> defaultEdges = Stream.ofNullable(page.getRecords())
 .flatMap(Collection::stream)
 .map(e -> (Edge<T>) new DefaultEdge<>(e, new DefaultConnectionCursor(String.valueOf(index.incrementAndGet()))))
 .toList();
 return new DefaultConnection<>(defaultEdges,
 new DefaultPageInfo(new DefaultConnectionCursor(String.valueOf(page.getCurrent())),
 new DefaultConnectionCursor(String.valueOf(page.getPages())),
 page.getCurrent() > 1,
 page.getCurrent() < page.getPages()));
 }
}

Graphql解析配置

	@DgsQuery
	public Connection<Film> filmList(@InputArgument("current") Integer current,
									 @InputArgument("size") Integer size,
									 DgsDataFetchingEnvironment dfe) {
		IPage<Film> page = new PageDTO<>(current, size);
		IPage<Film> pageResult = filmRepository.page(page);
		return ConnectionAssembler.convert(pageResult);
	}

将List查询改为返回Connection即可

测试

访问http://localhost:8080/graphiql即可看到在线查询页面

查看查询数量，确认是按照分页查询

总结

到此，DSG核心功能尝试基本完成，基本实现常用的Rest功能，同时集成方便，而且官方文档清晰，但目前开源社区还没有太多的基于DSG的系统集成样例，还需要在实践中评估摸索。

thoughtworks也从2016年开始关注graphql，目前给出的建议也是“评估”，可以进行小规模尝试并在合适的时候推广

We’ve seen many successful GraphQL implementations on our projects. We’ve seen some interesting patterns of use too, including GraphQL for server-side resource aggregation. That said, we’ve concerns about misuse of this framework and some of the problems that can occur. Examples include performance gotchas around N+1 queries and lots of boilerplate code needed when adding new models, leading to complexity. There are workarounds to these gotchas such as query caching. Even though it’s not a silver bullet, we still think it’s worth assessing as part of your architecture.

GraphQL实践6——Netflix Dgs Graphql N+1问题

Fri, 28 Oct 2022 16:05:51 +0800

N+1问题介绍

对于上一篇文章样例，如果要获取每个电影的演员名单，要执行如下动作

查询所有电影清单
遍历N个电影，查询对应电影的演员名单

总查询开销为N+1次查询，代价非常大，效率低

优化方案 DataLoader

对于一对一表关联的情况且每个关联对象只有一个值，可以直接使用BatchLoader

但实际上，对于大部分表关联情况，通常为一对多或者多对多，不保证每个关联都有值，此时需要使用MappedBatchLoader维护关联关系

维护多对多实体关系Map

public interface ActorService {
	Map<Integer, List<Actor>> listByFilmId(Collection<Integer> filmIds);
}

@Slf4j
@Service
@RequiredArgsConstructor
public class ActorServiceImpl implements ActorService {

	private final ActorRepository actorRepository;

	private final FilmActorRepository filmActorRepository;

	@Override
	public Map<Integer, List<Actor>> listByFilmId(Collection<Integer> filmIds) {
		List<FilmActor> filmActors = filmActorRepository.listByFilmId(filmIds);
		if (CollectionUtils.isEmpty(filmActors)) {
			return Collections.emptyMap();
		}
		Map<Integer, List<FilmActor>> filmActorMap = filmActors.stream().collect(Collectors.groupingBy(FilmActor::getFilmId));
		List<Integer> actorIds = filmActors.stream().map(FilmActor::getActorId).distinct().toList();
		List<Actor> actors = actorRepository.listByIds(actorIds);
		Map<Integer, Actor> actorsMap = Stream.ofNullable(actors).flatMap(Collection::stream).collect(Collectors.toMap(Actor::getActorId, Function.identity(), (e1, e2) -> e1));
		Map<Integer, List<Actor>> result = Maps.newHashMapWithExpectedSize(filmIds.size());
		filmActorMap.forEach((k, v) -> {
			List<Actor> actorList = Stream.ofNullable(filmActorMap.get(k)).flatMap(Collection::stream).map(e -> actorsMap.get(e.getActorId())).toList();
			result.put(k, actorList);
		});
		return result;
	}
}

Dgs MappedBatchLoader 配置

@DgsDataLoader(name = "actors")
@RequiredArgsConstructor
public class FilmActorsDataLoader implements MappedBatchLoader<Integer, List<Actor>> {

	private final ActorService actorService;

	@Override
	public CompletionStage<Map<Integer, List<Actor>>> load(Set<Integer> keys) {
		return CompletableFuture.supplyAsync(() -> actorService.listByFilmId(keys));
	}
}

测试

访问http://localhost:8080/graphiql即可看到在线查询页面

此时执行嵌套查询只会查询2次，一次查电影列表，一次查所有电影的Actor列表，非常快速

总结

使用BatchLoader实现对N+1问题优化，但还有一个潜在问题，即大数据分页，该样例中，有1000个电影，对应5000+演员，查询一次获取全量数据，对数据库压力较大，也不符合实际场景，还需要进行分页优化

GraphQL实践5——Netflix Dgs Graphql懒加载

Fri, 28 Oct 2022 16:04:43 +0800

问题背景

在graphql中，需要查询的字段由调用方传递，如果此时存在关联表才能获取的字段，但前端不需要该字段的时候，默认查询所有字段会带来较大开销

例如

type Actor {
 actorId: Int!
 firstName: String!
 lastName: String!
 lastUpdate: String
}

type Film {
 filmId: Int!
 title: String!
 description: String
 actors: [Actor]
}

type Query {
 filmList: [Film]
}

解决方案——懒加载

DGS框架中支持配置调用方传递了指定字段才读取对应的数据

配置懒加载

增加实体定义，模拟嵌套实体

Mybatis Plus配置

扫描配置

@Configuration
@MapperScan("top.fjy8018.graphsqldemo.mapper")
public class MybatisPlusConfig {
}

实体

表结构还是使用sakila样例数据库的表

@Data
public class Actor implements Serializable {

 @Serial
 private static final long serialVersionUID = 1L;

 /**
 * 联系人ID
 */
 @TableId(type = IdType.AUTO)
 private Integer actorId;

 private String firstName;

 private String lastName;

 private Date lastUpdate;

}

@Data
public class Film implements Serializable {

	@Serial
	private static final long serialVersionUID = 1L;

	/**
	 * 联系人ID
	 */
	@TableId(type = IdType.AUTO)
	private Integer filmId;

	private String title;

	private String description;

	private Integer releaseYear;

	private Integer languageId;

	private Integer originalLanguageId;

	private Integer rentalDuration;

	private BigDecimal rentalRate;

	private Integer length;

	private BigDecimal replacementCost;

	private String rating;

	private String specialFeatures;

	private Date lastUpdate;
}

@Data
public class FilmActor implements Serializable {

	@Serial
	private static final long serialVersionUID = 1L;

	/**
	 * 联系人ID
	 */
	@TableId(type = IdType.AUTO)
	private Integer actorId;

	private Integer filmId;

	private Date lastUpdate;
}

Mapper

public interface ActorMapper extends BaseMapper<Actor> {}
public interface FilmActorMapper extends BaseMapper<FilmActor> {}
public interface FilmMapper extends BaseMapper<Film> {}

DAO

public interface ActorRepository extends IService<Actor> {
}
public interface FilmActorRepository extends IService<FilmActor> {
	List<FilmActor> listByFilmId(@Size.List({@Size(min = 1, message = "至少要有一个元素")}) List<Integer> filmIds);
}
public interface FilmRepository extends IService<Film> {
}

@Validated
@Repository
@RequiredArgsConstructor
public class ActorRepositoryImpl extends ServiceImpl<ActorMapper, Actor> implements ActorRepository {
}
@Validated
@Repository
@RequiredArgsConstructor
public class FilmActorRepositoryImpl extends ServiceImpl<FilmActorMapper, FilmActor> implements FilmActorRepository {
	@Override
	public List<FilmActor> listByFilmId(List<Integer> filmIds) {
		return lambdaQuery().in(FilmActor::getFilmId, filmIds).list();
	}
}
@Validated
@Repository
@RequiredArgsConstructor
public class FilmRepositoryImpl extends ServiceImpl<FilmMapper, Film> implements FilmRepository {
}

Service

多表查询聚合逻辑

public interface ActorService {
	List<Actor> listByFilmId(Integer filmId);
}

@Slf4j
@Service
@RequiredArgsConstructor
public class ActorServiceImpl implements ActorService {

	private final ActorRepository actorRepository;

	private final FilmActorRepository filmActorRepository;

	@Override
	public List<Actor> listByFilmId(Integer filmId) {
		List<FilmActor> filmActors = filmActorRepository.listByFilmId(List.of(filmId));
		if (CollectionUtils.isEmpty(filmActors)) {
			return Collections.emptyList();
		}
		List<Integer> actorIds = filmActors.stream().map(FilmActor::getActorId).toList();
		return actorRepository.listByIds(actorIds);
	}
}

Graphql 查询解析器

@DgsComponent
@RequiredArgsConstructor
public class FilmDataFetcher {

	private final FilmRepository filmRepository;

	private final ActorService actorService;

	@DgsQuery
	public Collection<Film> filmList() {
		return filmRepository.list();
	}

	@DgsData(parentType = "Film")
	public List<Actor> actors(DgsDataFetchingEnvironment dfe) {
		Film film = dfe.getSource();
		return actorService.listByFilmId(film.getFilmId());
	}

	@DgsQuery
	public Film findOneFilm(@InputArgument Integer id) {
		return filmRepository.getById(id);
	}
}

增加DgsDataFetchingEnvironment入参，DGS会自动获取请求上下文参数

此处定义即为传入了actors参数才执行该方法获取对应的Actor集合，实现懒加载

测试

访问http://localhost:8080/graphiql即可看到在线查询页面

不访问Actor

此时可以看到日志输出，没有查询Actor表

访问Actor

此时DSG会执行N+1查询Actor表，性能损耗非常大

总结

对于表关联，开销较大字段，都可以使用DSG懒加载实现性能优化，但此时还是存在N+1查询性能问题，将在后面使用DataLoader优化

GraphQL实践4——Netflix Dgs Graphql集成Mybatis Plus

Fri, 28 Oct 2022 16:03:00 +0800

介绍

通过JPA或者Mybatis Plus集成Graphql框架已经很简便，但其实使用graphql-java集成过于底层，很多扩展内容实现并不方便，例如：

分页查询
资源懒加载
N+1问题

Netflix 基于长期的Graphql实践，2020年开源了DGS Framework，让解决上述问题更加简单，大量开源系统集成Graphql也是通过集成DGS组件

The DGS framework project started at Netflix in 2019 as internal teams began developing multiple GraphQL services. As 2020 wrapped up, Netflix decided to open source the framework and build a community around it.

集成Netflix DGS

官网：Home - DGS Framework (netflix.github.io)

引入依赖

技术栈：

SpringBoot 2.7.1
Mybatis Plus
JDK 17
Dgs SpringBoot

本次和上一篇文章一样，选择原因不在赘述

	<dependencyManagement>
 <dependencies>
 <dependency>
 <groupId>com.netflix.graphql.dgs</groupId>
 <artifactId>graphql-dgs-platform-dependencies</artifactId>
 <!-- The DGS BOM/platform dependency. This is the only place you set version of DGS -->
 <version>4.9.16</version>
 <type>pom</type>
 <scope>import</scope>
 </dependency>
 </dependencies>
 </dependencyManagement>

 <dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-validation</artifactId>
 </dependency>

 <dependency>
 <groupId>com.netflix.graphql.dgs</groupId>
 <artifactId>graphql-dgs-spring-boot-starter</artifactId>
 </dependency>

 <dependency>
 <groupId>org.projectlombok</groupId>
 <artifactId>lombok</artifactId>
 <optional>true</optional>
 </dependency>

 <dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <scope>runtime</scope>
 </dependency>
 <!-- mybatis-plus-boot-starter -->
 <dependency>
 <groupId>com.baomidou</groupId>
 <artifactId>mybatis-plus-boot-starter</artifactId>
 <version>3.5.2</version>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-test</artifactId>
 <scope>test</scope>
 </dependency>
 </dependencies>

配置文件

spring:
 datasource:
 driver-class-name: com.mysql.cj.jdbc.Driver
 username: root
 password: ****
 url: jdbc:mysql://localhost:3306/sakila?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
server:
 port: 8080
logging:
 level:
 top.fjy8018.graphsqldemo.mapper: DEBUG

dgs:
 graphql:
 schema-locations:
 - classpath*:graphql/*.graphqls

由于DGS默认扫描路径为classpath*:schema/**/*.graphql*，本次基于上一篇文章的工程配置，需要手动指定一下扫描文件目录

Mybatis Plus配置

扫描配置

@Configuration
@MapperScan("top.fjy8018.graphsqldemo.mapper")
public class MybatisPlusConfig {
}

实体

表结构还是使用sakila样例数据库的表

@Data
public class Actor implements Serializable {

 @Serial
 private static final long serialVersionUID = 1L;

 /**
 * 联系人ID
 */
 @TableId(type = IdType.AUTO)
 private Integer actorId;

 private String firstName;

 private String lastName;

 private Date lastUpdate;

}

Mapper

public interface ActorMapper extends BaseMapper<Actor> {
}

DAO

从分层模型定义上，MP自带的CRUD接口本质上还是一个DAO，故定义为Repository更加合适，不与业务逻辑Serice冲突

同时也建议QueryWrapper仅在对应的Repository使用，防止查询条件散落在各处

public interface ActorRepository extends IService<Actor> {
}

@Validated
@Repository
@RequiredArgsConstructor
public class ActorRepositoryImpl extends ServiceImpl<ActorMapper, Actor> implements ActorRepository {
}

Graphql 查询解析器

@DgsComponent
@RequiredArgsConstructor
public class ActorDataFetcher {

	private final ActorRepository actorRepository;

	@DgsQuery
	public Collection<Actor> actorList() {
		return actorRepository.list();
	}

	@DgsQuery
	public Actor findOneActor(@InputArgument Integer id) {
		return actorRepository.getById(id);
	}
}

type Query {
 actorList: [Actor]
 findOneActor(id : Int!): Actor
}

type Actor {
 actorId: Int!
 firstName: String!
 lastName: String!
 lastUpdate: String
}

此处集成和graphql-java-kickstart类似，也是十分简便，不指定别名默认将方法名映射到文件方法名

测试

访问http://localhost:8080/graphiql即可看到在线查询页面

总结

此处还看不出DGS与其他graphql-java组件的区别，都是集成简便，可以和任何数据源、ORM框架集成，后续将会逐步实践DGS特性，包括懒加载、N+1问题、分页组件等

GraphQL实践3——Spring-Graphql集成Mybatis Plus

Thu, 27 Oct 2022 15:37:00 +0800

介绍

考虑到国内大部分场景对接的是Mybatis或者Mybatis Plus生态，而不是JPA，同时Graphql版本也进一步迭代，故计划使用Mybatis Plus对接Graphql

集成过程

引入依赖

由于JDK已经发展到19，目前最新的LTS为17，我所在的公司也将生产升级到了JDK 17，未来更多新应用会直接基于17构建，故此处直接基于JDK17对接
SpringBoot版本为2.7.1，目前已知3.0.0 RC1还不兼容第三方graphql
此处不使用spring官方的starter，改为使用graphql-java-kickstart的starter，编写更加简单


 <dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>

 <dependency>
 <groupId>org.projectlombok</groupId>
 <artifactId>lombok</artifactId>
 <optional>true</optional>
 </dependency>

 <!-- graphql-spring-boot-starter -->
 <dependency>
 <groupId>com.graphql-java-kickstart</groupId>
 <artifactId>graphql-spring-boot-starter</artifactId>
 <version>12.0.0</version>
 </dependency>

 <dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <scope>runtime</scope>
 </dependency>
 <!-- mybatis-plus-boot-starter -->
 <dependency>
 <groupId>com.baomidou</groupId>
 <artifactId>mybatis-plus-boot-starter</artifactId>
 <version>3.5.2</version>
 </dependency>
 <!-- querydsl-core -->
 <dependency>
 <groupId>com.querydsl</groupId>
 <artifactId>querydsl-core</artifactId>
 </dependency>
 
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-test</artifactId>
 <scope>test</scope>
 </dependency>
 </dependencies>

配置文件

spring:
 datasource:
 driver-class-name: com.mysql.cj.jdbc.Driver
 username: root
 password: ****
 url: jdbc:mysql://localhost:3306/sakila?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
server:
 port: 8080
graphql:
 tools:
 schema-location-pattern: graphql/*.graphqls
 graphiql:
 # 开启可交互页面，用于调试
 enabled: true
logging:
 level:
 top.fjy8018.graphsqldemo.mapper: DEBUG

Mybatis Plus配置

扫描配置

@Configuration
@MapperScan("top.fjy8018.graphsqldemo.mapper")
public class MybatisPlusConfig {
}

实体

@Data
public class Actor implements Serializable {

 @Serial
 private static final long serialVersionUID = 1L;

 /**
 * 联系人ID
 */
 @TableId(type = IdType.AUTO)
 private Integer actorId;

 private String firstName;

 private String lastName;

 private Date lastUpdate;

}

Mapper

public interface ActorMapper extends BaseMapper<Actor> {
}

DAO

public interface ActorRepository extends IService<Actor> {
}

@Validated
@Repository
@RequiredArgsConstructor
public class ActorRepositoryImpl extends ServiceImpl<ActorMapper, Actor> implements ActorRepository {
}

Graphql 查询解析器

@Component
@AllArgsConstructor
public class ActorGraphQLQueryResolver implements GraphQLQueryResolver {

 private final ActorRepository actorRepository;

 public Collection<Actor> actorList() {
 return actorRepository.list();
 }

 public Actor findOneActor(Integer id) {
 return actorRepository.getById(id);
 }
}

查询文件定义在resources/graphql/actor.graphqls

type Query {
 actorList: [ActorEntity]
 findOneActor(id : ID!): ActorEntity
}

type ActorEntity {
 actorId: ID!
 firstName: String!
 lastName: String!
 lastUpdate: String
}

测试

访问http://localhost:8080/graphiql即可看到在线查询页面

总结

依托Mybatis Plus强大的自带CRUD方法，可以实现和JPA类似的快速对接

GraphQL实践2——Spring-GraphQL集成JPA与MySQL

Mon, 15 Nov 2021 15:38:00 +0800

介绍

上一篇介绍到用第三方库集成GraphQL，目前spring-graphql项目已经出到1.0.0-M3版本，属于内部预览版，此处尝鲜验证

引入依赖

由于SpringBoot 2.6.0还未发布，因此需要引入较多依赖

<dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <dependency>
 <groupId>org.projectlombok</groupId>
 <artifactId>lombok</artifactId>
 <optional>true</optional>
 </dependency>
 <dependency>
 <groupId>org.springframework.experimental</groupId>
 <artifactId>graphql-spring-boot-starter</artifactId>
 <version>1.0.0-M3</version>
 </dependency>
 <!--升级到Spring Boot 2.6后可以移除-->
 <dependency>
 <groupId>org.springframework.data</groupId>
 <artifactId>spring-data-commons</artifactId>
 <version>2.6.0-RC1</version>
 </dependency>
 <dependency>
 <groupId>org.springframework.data</groupId>
 <artifactId>spring-data-jpa</artifactId>
 <version>2.6.0-RC1</version>
 </dependency>
 <!-- https://mvnrepository.com/artifact/org.hibernate.javax.persistence/hibernate-jpa-2.1-api -->
 <dependency>
 <groupId>org.hibernate.javax.persistence</groupId>
 <artifactId>hibernate-jpa-2.1-api</artifactId>
 <version>1.0.2.Final</version>
 </dependency>
 <!-- https://mvnrepository.com/artifact/com.querydsl/querydsl-jpa -->
 <dependency>
 <groupId>com.querydsl</groupId>
 <artifactId>querydsl-jpa</artifactId>
 <version>4.4.0</version>
 </dependency>
 <!-- https://mvnrepository.com/artifact/com.querydsl/querydsl-apt -->
 <dependency>
 <groupId>com.querydsl</groupId>
 <artifactId>querydsl-apt</artifactId>
 <version>4.4.0</version>
 </dependency>
 <!-- https://mvnrepository.com/artifact/javax.annotation/javax.annotation-api -->
 <dependency>
 <groupId>javax.annotation</groupId>
 <artifactId>javax.annotation-api</artifactId>
 </dependency>
 <dependency>
 <groupId>com.querydsl</groupId>
 <artifactId>querydsl-core</artifactId>
 </dependency>
 <dependency>
 <groupId>com.querydsl</groupId>
 <artifactId>querydsl-jpa</artifactId>
 </dependency>
 <dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <scope>runtime</scope>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-data-jpa</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-test</artifactId>
 <scope>test</scope>
 </dependency>
</dependencies>

引入里程碑仓库

由于还没有GA，所以要引入里程碑仓库

<repositories>
 <repository>
 <id>spring-milestones</id>
 <name>Spring Milestones</name>
 <url>https://repo.spring.io/milestone</url>
 </repository>
 <repository>
 <id>spring-snapshots</id>
 <name>Spring Snapshots</name>
 <url>https://repo.spring.io/snapshot</url>
 <snapshots>
 <enabled>true</enabled>
 </snapshots>
 </repository>
</repositories>

引入插件

由于使用了dsl动态生成，还要引入注解处理器

<build>
 <plugins>
 <plugin>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-maven-plugin</artifactId>
 <configuration>
 <excludes>
 <exclude>
 <groupId>org.projectlombok</groupId>
 <artifactId>lombok</artifactId>
 </exclude>
 </excludes>
 </configuration>
 </plugin>
 <!-- added for QueryDsl-->
 <plugin>
 <groupId>com.mysema.maven</groupId>
 <artifactId>apt-maven-plugin</artifactId>
 <version>1.1.3</version>
 <executions>
 <execution>
 <goals>
 <goal>process</goal>
 </goals>
 <configuration>
 <outputDirectory>target/generated-sources/java</outputDirectory>
 <processor>com.querydsl.apt.jpa.JPAAnnotationProcessor</processor>
 </configuration>
 </execution>
 </executions>
 </plugin>
 </plugins>
</build>

SpringBoot 配置

编写配置文件

spring:
 datasource:
 driver-class-name: com.mysql.cj.jdbc.Driver
 username: root
 password: "****"
 url: jdbc:mysql://localhost:3306/sakila?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
 jpa:
 hibernate:
 ddl-auto: none
 show-sql: true
 database-platform: org.hibernate.dialect.MySQL55Dialect
 properties:
 hibernate:
 format_sql: true
 use_sql_comments: true
 graphql:
 path: /graphql
 schema:
 locations: classpath:graphql/
 fileExtensions: .graphqls, .gqls
 printer:
 enabled: true
server:
 port: 8080

实体类

package top.fjy8018.graphsqldemo.entity;

import lombok.Data;

import javax.persistence.*;
import java.sql.Timestamp;
import java.util.Objects;

/**
 * 演员表实体类
 *
 * @author F嘉阳
 * @date 2021/11/5 10:34
 */
@Data
@Entity
@Table(name = "actor", schema = "sakila")
public class ActorEntity {
 @Id
 @Column(name = "actor_id", nullable = false)
 private Integer actorId;

 @Column(name = "first_name", nullable = false, length = 45)
 private String firstName;

 @Column(name = "last_name", nullable = false, length = 45)
 private String lastName;

 @Column(name = "last_update", nullable = false)
 private Date lastUpdate;

}

DAO

DAO直接继承dsl相关处理器，可自动配对增删改查方法，相比第三方库更加简便

package top.fjy8018.graphsqldemo.repository;

import org.springframework.data.querydsl.QuerydslPredicateExecutor;
import org.springframework.data.repository.CrudRepository;
import org.springframework.graphql.data.GraphQlRepository;
import top.fjy8018.graphsqldemo.entity.ActorEntity;

/**
 * 演员表DAO
 *
 * @author F嘉阳
 * @date 2021/11/5 10:35
 */
@GraphQlRepository
public interface ActorEntityRepository extends
 CrudRepository<ActorEntity, Integer>, QuerydslPredicateExecutor<ActorEntity> {
}

Graphql资源定义

在resources/graphql下定义接口和实体文件

接口声明和实体定义schema.graphqls

type Query {
 findOneActor(actorId : ID!): ActorEntity
 actorList: [ActorEntity]
}

type ActorEntity {
 actorId: ID!
 firstName: String!
 lastName: String!
 lastUpdate: String
}

接口定义acotrEntity.graphql

query findOneActor($id: ID!) {
 findOneActor(actorId: $id) {
 actorId
 firstName
 lastName
 lastUpdate
 }
}

query actorList {
 actorList{
 actorId
 }
}

启动测试

Spring-Graphql默认不包含可视化界面，此处使用postman进行测试

唯一查询

列表查询

总结

使用Spring官方组件好处在于和Spring生态集成度很高，如果本身就采用Jpa方式进行业务开发，迁移更加方便，需要开发的代码也很少。

样例源码地址

FJiayang/graphql-demo

GraphQL实践1——集成JPA与MySQL

Fri, 05 Nov 2021 17:41:00 +0800

介绍

官方定义：

GraphQL 既是一种用于 API 的查询语言也是一个满足你数据查询的运行时。 GraphQL 对你的 API 中的数据提供了一套易于理解的完整描述，使得客户端能够准确地获得它需要的数据，而且没有任何冗余，也让 API 更容易地随着时间推移而演进，还能用于构建强大的开发者工具。

中文官网：

GraphQL — A query language for your API

集成方案选择

GraphQL经过近几年的发展，SpringBoot官方、第三方都提供了starter

SpringBoot官方提供的starter

Spring GraphQL

第三方提供的starter

graphql-spring-boot

两者活跃度都还不错，但考虑到SpringBoot官方的依赖库还未GA，而且使用起来与Spring家族耦合过大，最终决定采用第三方的starter

集成过程

数据库配置

此处采用MySQL数据库，数据内容采用MySQL官方样例sakila数据，表结构和数据地址如下

sakila database下载地址

导入后如下

工程配置

引入最新的SpringBoot框架，依赖如下

<dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>

 <dependency>
 <groupId>org.projectlombok</groupId>
 <artifactId>lombok</artifactId>
 <optional>true</optional>
 </dependency>

 <!-- https://mvnrepository.com/artifact/com.graphql-java-kickstart/graphql-spring-boot-starter -->
 <dependency>
 <groupId>com.graphql-java-kickstart</groupId>
 <artifactId>graphql-spring-boot-starter</artifactId>
 <version>12.0.0</version>
 </dependency>

 <dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <scope>runtime</scope>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-data-jpa</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-test</artifactId>
 <scope>test</scope>
 </dependency>
</dependencies>

增加数据库配置

spring:
 datasource:
 driver-class-name: com.mysql.cj.jdbc.Driver
 username: root
 password: "****"
 url: jdbc:mysql://localhost:3306/sakila?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
 jpa:
 hibernate:
 ddl-auto: update
 show-sql: true
 database-platform: org.hibernate.dialect.MySQL55Dialect
 properties:
 hibernate:
 format_sql: true
 use_sql_comments: true
server:
 port: 8080
graphql:
 tools:
 schema-location-pattern: graphql/*.graphqls
 graphiql:
 # 开启可交互页面，用于调试
 enabled: true

实体映射

新增实体映射，此处只映射Actor表作为样例

package top.fjy8018.graphsqldemo.entity;

import lombok.Data;

import javax.persistence.*;
import java.sql.Timestamp;
import java.util.Objects;

/**
 * 演员表实体映射
 *
 * @author F嘉阳
 * @date 2021/11/5 10:34
 */
@Data
@Entity
@Table(name = "actor", schema = "sakila")
public class ActorEntity {
 @Id
 @Column(name = "actor_id", nullable = false)
 private Integer actorId;

 @Column(name = "first_name", nullable = false, length = 45)
 private String firstName;

 @Column(name = "last_name", nullable = false, length = 45)
 private String lastName;

 @Column(name = "last_update", nullable = false)
 private Timestamp lastUpdate;
}

新增DAO

package top.fjy8018.graphsqldemo.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import top.fjy8018.graphsqldemo.entity.ActorEntity;

/**
 * 演员表DAO
 *
 * @author F嘉阳
 * @date 2021/11/5 10:35
 */
public interface ActorEntityRepository extends JpaRepository<ActorEntity, Integer> {
}

新增查询接口配置

在resources/graphql下新增文件actor.graphqls

type Query {
 actorList: [ActorEntity]
 findOneActor(id : ID!): ActorEntity
}

type ActorEntity {
 actorId: ID!
 firstName: String!
 lastName: String!
 lastUpdate: String
}

新增查询解析器

package top.fjy8018.graphsqldemo.resolver;

import graphql.kickstart.tools.GraphQLQueryResolver;
import lombok.AllArgsConstructor;
import org.springframework.stereotype.Component;
import top.fjy8018.graphsqldemo.entity.ActorEntity;
import top.fjy8018.graphsqldemo.repository.ActorEntityRepository;

import java.util.Collection;

/**
 * 演员表GraphQL查询解析器
 *
 * @author F嘉阳
 * @date 2021/11/5 16:27
 */
@Component
@AllArgsConstructor
public class ActorGraphQLQueryResolver implements GraphQLQueryResolver {

 private final ActorEntityRepository actorRepository;

 public Collection<ActorEntity> actorList() {
 return actorRepository.findAll();
 }

 public ActorEntity findOneActor(Integer id) {
 return actorRepository.findById(id).orElse(null);
 }
}

启动验证

启动工程后，浏览器打开http://localhost:8080/graphiql

列表查询

由于采用交互式页面，输入也会有语法提示，比较方便

唯一查询

优缺点分析

优点

接口定义清晰，配置即接口
前端按需获取字段，减少数据传输量
接口整合、演进更加便利

缺点

减少字段个数对后端实现没有变化，并不能提升数据库性能

样例源码地址

FJiayang/graphql-demo