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
代码语言：txt复制 <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
代码语言：txt复制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
代码语言：txt复制@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
代码语言：txt复制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
代码语言：txt复制public interface ActorRepository extends IService<Actor> {
}@Validated
@Repository
@RequiredArgsConstructor
public class ActorRepositoryImpl extends ServiceImpl<ActorMapper, Actor> implements ActorRepository {
}Graphql 查询解析器
代码语言：txt复制@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
image-20221027220330451.png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
