Getting started

A working version of this example can be found at https://github.com/graphql-java-kickstart/samples/tree/master/servlet-hello-world.

Build with Gradle

First you set up a basic build script. You can use any build system you like, but the code you need to work with Gradle and Maven is included here.

Create a Gradle build file

Make sure mavenCentral is among your repositories. The example build script below uses org.gretty to provide a webserver to show a working example. You need to add the jcenter repository as well to be able to pull in all dependencies required by gretty.

plugins {
    id 'war'
    id 'idea'
    id 'org.gretty' version '2.2.0'
}

repositories {
    mavenCentral()
    jcenter()
}

dependencies {
    compile 'com.graphql-java-kickstart:graphql-java-servlet:7.0.0'
}

Build with Maven

First you set up a basic build script. You can use any build system you like, but the code you need to work with Gradle and Maven is included here. We’re assuming you already have a basic understanding of the build system of your choosing and how to use it. So instead of providing fully functioning build script we only provide the sections needed to add graphql-java-servlet to your application.

Update your Maven pom file

Add the graphql-java-servlet dependency to your depencies section:

<dependency>
  <groupId>com.graphql-java-kickstart</groupId>
  <artifactId>graphql-java-servlet</artifactId>
  <version>7.0.0</version>
</dependency>

Create a Servlet class

Create a servlet class extending SimpleGraphQLHttpServlet. This is the basic “Hello world” example. It creates the GraphQL Query { hello } that can be executed and which will respond with “world”. It creates the GraphQL schema programmatically as shown in the getting started example from graphql-java.

@WebServlet(name = "HelloServlet", urlPatterns = {"graphql"}, loadOnStartup = 1)
public class HelloServlet extends GraphQLHttpServlet {

  @Override
  protected GraphQLConfiguration getConfiguration() {
    return GraphQLConfiguration.with(createSchema()).build();
  }

  private GraphQLSchema createSchema() {
    String schema = "type Query{hello: String}";

    SchemaParser schemaParser = new SchemaParser();
    TypeDefinitionRegistry typeDefinitionRegistry = schemaParser.parse(schema);

    RuntimeWiring runtimeWiring = newRuntimeWiring()
        .type("Query", builder -> builder.dataFetcher("hello", new StaticDataFetcher("world")))
        .build();

    SchemaGenerator schemaGenerator = new SchemaGenerator();
    return schemaGenerator.makeExecutableSchema(typeDefinitionRegistry, runtimeWiring);
  }

}

Run the application

To run the application, execute the gradle appRun task that was added by org.gretty. If all goes well it will start a jetty webserver and expose the Hello world Servlet on localhost. It will log the exact endpoint, like below:

17:45:53 INFO  Jetty 9.2.24.v20180105 started and listening on port 8080
17:45:53 INFO  graphql-java-servlet-hello-world runs at:
17:45:53 INFO    http://localhost:8080/graphql-java-servlet-hello-world

> Task :graphql-java-servlet-hello-world:appRun
Press any key to stop the server.

Send a GraphQL Query

You can now send a GraphQL query to your local servlet, for example using Insomnia. In this case the URL to post the GraphQL query to is http://localhost:8080/graphql-java-servlet-hello-world/graphql.

The following GraphQL query is what the example implementation supports:

query {
    test
}

Our Hello Servlet will respond with:

{
    "data": {
        "hello": "world"
    }
}