QraphQL in Spring Boot

QraphQL in Spring Boot

1. Add Dependencies

If you’re using Maven, add the following to your pom.xml:

<dependencies>
    <!-- Spring Boot Starter Web -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <!-- GraphQL Starter -->
    <dependency>
        <groupId>com.graphql-java</groupId>
        <artifactId>graphql-spring-boot-starter</artifactId>
        <version>5.0.2</version>
    </dependency>

    <!-- GraphQL Tools (schema parsing) -->
    <dependency>
        <groupId>com.graphql-java-kickstart</groupId>
        <artifactId>graphql-java-tools</artifactId>
        <version>11.0.0</version>
    </dependency>

    <!-- Optional: GraphiQL UI -->
    <dependency>
        <groupId>com.graphql-java-kickstart</groupId>
        <artifactId>graphiql-spring-boot-starter</artifactId>
        <version>11.1.0</version>
    </dependency>
</dependencies>

(Or use the latest versions if you start a new project.)

2. Define a GraphQL Schema

Create a schema file under src/main/resources/graphql/schema.graphqls:

type Book {
    id: ID!
    title: String!
    author: String!
}

type Query {
    getBookById(id: ID!): Book
    getAllBooks: [Book]
}

This defines a Book type and queries to fetch books.

3. Create a Model Class

package com.example.demo.model;

public class Book {
    private String id;
    private String title;
    private String author;

    public Book(String id, String title, String author) {
        this.id = id;
        this.title = title;
        this.author = author;
    }

    // getters & setters
    public String getId() { return id; }
    public String getTitle() { return title; }
    public String getAuthor() { return author; }
}

4. Create a Service Layer

package com.example.demo.service;

import com.example.demo.model.Book;
import org.springframework.stereotype.Service;

import java.util.Arrays;
import java.util.List;

@Service
public class BookService {
    private final List<Book> books = Arrays.asList(
            new Book("1", "GraphQL for Beginners", "Alice"),
            new Book("2", "Spring Boot in Action", "Bob")
    );

    public Book getBookById(String id) {
        return books.stream().filter(b -> b.getId().equals(id)).findFirst().orElse(null);
    }

    public List<Book> getAllBooks() {
        return books;
    }
}

5. Create a GraphQL Resolver

package com.example.demo.resolver;

import com.coxautodev.graphql.tools.GraphQLQueryResolver;
import com.example.demo.model.Book;
import com.example.demo.service.BookService;
import org.springframework.stereotype.Component;

import java.util.List;

@Component
public class BookQueryResolver implements GraphQLQueryResolver {

    private final BookService bookService;

    public BookQueryResolver(BookService bookService) {
        this.bookService = bookService;
    }

    public Book getBookById(String id) {
        return bookService.getBookById(id);
    }

    public List<Book> getAllBooks() {
        return bookService.getAllBooks();
    }
}

6. Run the Application

Run your Spring Boot app (@SpringBootApplication).
GraphQL endpoint is available at:

7. Example Queries

Query all books:

query {
  getAllBooks {
    id
    title
    author
  }
}

Query a single book:

query {
  getBookById(id: "1") {
    id
    title
    author
  }
}

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