Spring Boot集成Graphql快速入门Demo

1.Graphql介绍

GraphQL 是一个用于 API 的查询语言，是一个使用基于类型系统来执行查询的服务端运行时（类型系统由你的数据定义）。GraphQL 并没有和任何特定数据库或者存储引擎绑定，而是依靠你现有的代码和数据支撑。

优势

GraphQL 速度快，并且比较稳定，GraphQL 的操作是在数据层面的，所以比较快。
GraphQL 可以获取更多的资源，当查询一个数据的时候，不止是这个数据，甚至可以很快地查询到数据引用的另一个数据。GraphQL 可以在单个请求中去获取尽量多的数据，并且在弱网状态下，GraphQL 依旧表现出色。
GraphQL 是单端点查询，并在此端点中去完成所有的查询。
GraphQL 的可持续性非常出色，无论是新字段、还是旧字段，它都能很好地去处理，可维护性也极佳。
GraphQL 具有向下兼容的特性，就算是很久很久以前的功能，GraphQL 还是能很好地去兼容它，保证旧版本的正常运行，同时又不影响新功能的加入以及整体的稳定性。这样做的好处就是，不需要去担忧版本号问题了。
GraphQL 具有强类型，在 GraphQL 的查询中，一个级别对应一个强类型，这个类型充当一个字段的描述。这样的好处就是，在查询之前，可以校验出错误并提示，方便定位问题，提高性能。
自省：可以查询 GraphQL 服务器支持的类型。这为工具和客户端软件创建了一个强大的平台，可以在这些信息的基础上构建静态类型语言的代码生成、我们的应用程序框架、Relay 或 GraphiQL 等 IDE。
GraphQL 支持使用者去决定服务器支持的类型。这样的好处就是，给很多使用 GraphQL 的工具或者端建立了一个比较成熟且强大的应用平台，通过这个平台，一些框架、工具得到不断地优化提升。

劣势

GraphQL 无法完成深度查询，所以无法对于未知深度的数据进行一次性查询。
GraphQL 具有非常死板的响应结构，你必须遵从这个结构去查询数据，或者自己添加一个转换器来转换。
GraphQL 无法进行网络级别的缓存，你必须使用另外别的办法进行持久查询。
GraphQL 默认没有上传文件的功能，GraphQL 也不接收文件类型的参数，但是你可以使用 REST 的方式进行上传文件，达到上传文件的目的。
GraphQL 的执行是不可预测的，因为 GraphQL 太过于灵活了。
同样的一个简单的 API，GraphQL 会表现得很复杂，所以建议简单 API 使用 RSET。

2.mysql环境搭建

参考代码仓库里面的mysql模块，这里只贴出docker-compose.yml

version: '3'
services:mysql:image: registry.cn-hangzhou.aliyuncs.com/zhengqing/mysql:5.7container_name: mysql_3306restart: unless-stopped                                   volumes:- "./mysql/my.cnf:/etc/mysql/my.cnf"- "./mysql/init-file.sql:/etc/mysql/init-file.sql"- "./mysql/data:/var/lib/mysql"
#      - "./mysql/conf.d:/etc/mysql/conf.d"- "./mysql/log/mysql/error.log:/var/log/mysql/error.log"- "./mysql/docker-entrypoint-initdb.d:/docker-entrypoint-initdb.d" # init sql script directory -- tips: it can be excute  when `/var/lib/mysql` is emptyenvironment:                        # set environment,equals docker run -eTZ: Asia/ShanghaiLANG: en_US.UTF-8MYSQL_ROOT_PASSWORD: root         # set root passwordMYSQL_DATABASE: demo              # init database nameports:                              # port mappping- "3306:3306"

运行

docker-compose -f docker-compose.yml -p mysql5.7 up -d

初始化脚本

CREATE DATABASE IF NOT EXISTS `BOOK_API_DATA`;
USE `BOOK_API_DATA`;CREATE TABLE IF NOT EXISTS `Book` (`id` int(20) NOT NULL AUTO_INCREMENT,`name` varchar(255) DEFAULT NULL,`pageCount` varchar(255) DEFAULT NULL,PRIMARY KEY (`id`),UNIQUE KEY `Index_name` (`name`)) ENGINE=InnoDB AUTO_INCREMENT=235 DEFAULT CHARSET=utf8;CREATE TABLE `Author` (`id` INT(20) NOT NULL AUTO_INCREMENT,`firstName` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8_general_ci',`lastName` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8_general_ci',`bookId` INT(20) NULL DEFAULT NULL,PRIMARY KEY (`id`) USING BTREE,UNIQUE INDEX `Index_name` (`firstName`) USING BTREE,INDEX `FK_Author_Book` (`bookId`) USING BTREE,CONSTRAINT `FK_Author_Book` FOREIGN KEY (`bookId`) REFERENCES `BOOK_API_DATA`.`Book` (`id`) ON UPDATE CASCADE ON DELETE CASCADE
)COLLATE='utf8_general_ci'
ENGINE=InnoDB
AUTO_INCREMENT=6
;INSERT INTO `Book` (`id`, `name`, `pageCount`) VALUES (1, 'the golden ticket', '255');
INSERT INTO `Book` (`id`, `name`, `pageCount`) VALUES (2, 'coding game', '300');INSERT INTO `Author` (`id`, `firstName`, `LastName`, `bookId`) VALUES (4, 'Brendon', 'Bouchard', 1);
INSERT INTO `Author` (`id`, `firstName`, `LastName`, `bookId`) VALUES (5, 'John', 'Doe', 2);

3.代码工程

实验目标

实现一个基于graphql查询的例子

实现过程

1. 定义Schema，Schema使用GraphQL Schema Definition Language (SDL)来定义

2. 实现Resolver，Resolver函数负责从数据源中获取请求的数据

3. 配置和启动GraphQL服务器，要启动GraphQL服务器，你需要安装相应的依赖和配置服务器

pomxml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><parent><artifactId>springboot-demo</artifactId><groupId>com.et</groupId><version>1.0-SNAPSHOT</version></parent><modelVersion>4.0.0</modelVersion><artifactId>GraphQL</artifactId><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target><kotlin.version>1.5.0</kotlin.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>com.graphql-java-kickstart</groupId><artifactId>graphql-spring-boot-starter</artifactId><version>12.0.0</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency><dependency><groupId>com.graphql-java-kickstart</groupId><artifactId>graphql-java-tools</artifactId><version>12.0.0</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope><exclusions><exclusion><groupId>org.junit.vintage</groupId><artifactId>junit-vintage-engine</artifactId></exclusion></exclusions></dependency><dependency><groupId>com.google.guava</groupId><artifactId>guava</artifactId><version>26.0-jre</version></dependency><dependency><groupId>org.apache.tomcat.embed</groupId><artifactId>tomcat-embed-jasper</artifactId><scope>provided</scope></dependency></dependencies>
</project>

GraphQLQueryResolver

package com.et.graphql.queryresolvers;import com.et.graphql.model.Author;
import com.et.graphql.model.Book;
import com.et.graphql.repository.AuthorRepository;
import com.et.graphql.repository.BookRepository;
import graphql.kickstart.tools.GraphQLQueryResolver;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;@Component
public class BookQuery implements GraphQLQueryResolver{@AutowiredBookRepository bookRepository;@AutowiredAuthorRepository authorRepository;public Iterable<Book> allBook(){return bookRepository.findAll();}public Book getBookByName(String name){return bookRepository.findBookByName(name);}public Iterable<Author> allAuthor(){return authorRepository.findAll();}}

package com.et.graphql.queryresolvers;import com.et.graphql.model.Book;
import com.et.graphql.repository.BookRepository;
import graphql.kickstart.tools.GraphQLMutationResolver;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;import java.util.Optional;@Component
public class BookMutation implements GraphQLMutationResolver {@AutowiredBookRepository bookRepository;public Book newBook(String name, String pageCount){Book book =  new Book();book.setName(name);book.setPageCount(pageCount);return bookRepository.save(book);}public Book deleteBook(Integer id){Book deleteBook = new Book();Optional<Book> findBook =  bookRepository.findById(id);if(findBook.isPresent()){bookRepository.delete(findBook.get());deleteBook = findBook.get();}return deleteBook;}
}

package com.et.graphql.queryresolvers;import com.et.graphql.model.Author;
import com.et.graphql.model.Book;
import com.et.graphql.repository.AuthorRepository;
import graphql.kickstart.tools.GraphQLResolver;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;@Component
public class BookAuthorResolver implements GraphQLResolver<Book> {@AutowiredAuthorRepository authorRepository;public Author getAuthor(Book book){return authorRepository.findAuthorByBookId(book.getId());}
}

graphqls(/resources/graphql)

type Book {id: Intname: StringpageCount: Stringauthor: Author
}type Query {allBook: [Book]allAuthor:[Author]getBookByName(name: String): Book
}type Mutation {newBook(name: String!, pageCount: String): BookdeleteBook(id:Int!):Book
}type Author {id: IntfirstName: StringlastName: StringbookId: Int
}

model

package com.et.graphql.model;import javax.persistence.*;@Entity
@Table(name = "Author", schema = "BOOK_API_DATA")
public class Author {@Id@GeneratedValue(strategy = GenerationType.AUTO)Integer id;@Column(name = "firstname")String firstName;@Column(name = "lastname")String lastName;@Column(name = "bookid")Integer bookId;public Author(Integer id, String firstName, String lastName, Integer bookId) {this.id = id;this.firstName = firstName;this.lastName = lastName;this.bookId = bookId;}public Author() {}public Integer getId() {return id;}public String getFirstName() {return firstName;}public String getLastName() {return lastName;}public void setId(Integer id) {this.id = id;}public void setFirstName(String firstName) {this.firstName = firstName;}public void setLastName(String lastName) {this.lastName = lastName;}public Integer getBookId() {return bookId;}public void setBookId(Integer bookId) {this.bookId = bookId;}
}

package com.et.graphql.model;import javax.persistence.*;@Entity
@Table(name = "Book", schema = "BOOK_API_DATA")
public class Book {@Id@GeneratedValue(strategy = GenerationType.AUTO)private Integer id;private String name;@Column(name = "pagecount")private String pageCount;public Book(Integer id, String name, String pageCount) {this.id = id;this.name = name;this.pageCount = pageCount;}public Book() {}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPageCount() {return pageCount;}public void setPageCount(String pageCount) {this.pageCount = pageCount;}
}

repository

package com.et.graphql.repository;import com.et.graphql.model.Author;
import org.springframework.data.repository.CrudRepository;public interface AuthorRepository extends CrudRepository<Author, Integer> {Author findAuthorByBookId(Integer bookId);
}

package com.et.graphql.repository;import com.et.graphql.model.Book;
import org.springframework.data.repository.CrudRepository;public interface BookRepository extends CrudRepository<Book, Integer> {Book findBookByName(String name);
}

DemoApplication.java

package com.et.graphql;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;@SpringBootApplication
@ComponentScan(basePackages = "com.et.graphql.queryresolvers")
public class BookAPIApplication {public static void main(String[] args) {SpringApplication.run(BookAPIApplication.class, args);}}

application.yaml

spring.jpa.hibernate.ddl-auto=none
spring.jpa.database=mysql
spring.jpa.open-in-view=true
spring.jpa.show-sql=true
server.port=8088
#logging.level.org.hibernate=DEBUG
logging.level.org.hibernate.SQL=DEBUG
spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl
spring.jpa.hibernate.use-new-id-generator-mappings= false# book api db"
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/demo?useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=root

以上只是一些关键代码，所有代码请参见下面代码仓库