GraphQL Java Spring

Status

Version 2.0 is released.

We have a spectrum chat for general questions.

Overview

This project integrates GraphQL Java into Spring/Spring Boot, by enabling query execution via HTTP.

While the GraphQL Specification itself doesn't specify any transport protocol there is a quasi standard how to do it described here and this project follows this quasi standard.

Goals / Design:

• Just HTTP JSON: the current focus is on HTTP execution via JSON.
• Minimal Dependencies: the only dependencies are GraphQL Java and Spring projects (including Jackson for JSON handling).
• No additional abstraction layer on top of GraphQL Java: GraphQL Java is meant to be used directly.

Supported HTTP Requests

As outlined in https://graphql.org/learn/serving-over-http this project supports:

1. GET request with query, operationName and variables parameters. The variable parameters are json encoded
2. POST request with body application/json and keys query (string), operationName (string) and variables (map).

Both produce application/json.

Support for webmvc and webflux

We support both spring web types: the fully non-blocking webflux and the traditional servlet based webmvc.

Please see here in the spring documentation itself about the differences.

Artifacts

There are four different artifacts: (all with group id com.graphql-java)

1. graphql-java-spring-webflux
2. graphql-java-spring-boot-starter-webflux
3. graphql-java-spring-webmvc
4. graphql-java-spring-boot-starter-webmvc

Getting started with Spring Boot (webflux and webmvc)

The Spring Boot Starter artifact provides a HTTP endpoint on ${graphql.url} with the default value "/graphql" just by being on the classpath.

The only requirement is to have a Bean of type graphql.GraphQL available.

Add the following dependency to your build.gradle (make sure mavenCentral() is among your repos)

for webflux:

dependencies {
    implementation "com.graphql-java:graphql-java-spring-boot-starter-webflux:2.0"
}

for webmvc:

dependencies {
    implementation "com.graphql-java:graphql-java-spring-boot-starter-webmvc:2.0"
}

or to your pom.xml

for webflux

<dependency>
    <groupId>com.graphql-java</groupId>
    <artifactId>graphql-java-spring-boot-starter-webflux</artifactId>
    <version>2.0</version>
</dependency>

for webmvc:

<dependency>
    <groupId>com.graphql-java</groupId>
    <artifactId>graphql-java-spring-boot-starter-webmvc</artifactId>
    <version>2.0</version>
</dependency>

Ways to customize

Properties

The following properties are currently available:

Property	Description	Default Value
graphql.url	the endpoint url	graphql

Beans

The following Beans can be overridden by providing a different implementation.

Interface	Description
GraphQLInvocation	Executes one request. The default impl just calls the provided GraphQL bean.
ExecutionResultHandler	Takes a ExecutionResult and sends the result back to the client. The default impl returns ExecutionResult.toSpecification() as json.