GraphQL API with Spring Boot

This project demonstrates how to build a GraphQL API using Spring Boot, JPA, and MySQL.

Steps to Set Up

1. Create a Spring Boot Project Use Spring Initializr and add dependencies:

   • spring-boot-starter-data-jpa
   • spring-boot-starter-graphql
   • spring-boot-starter-web
   • mysql-connector-j

2. Define Entities Create User and Order entities with JPA annotations.

3. Create Repositories
   Use JpaRepository to manage entities:

   public interface UserRepository extends JpaRepository<User, Long> {}
   public interface OrderRepository extends JpaRepository<Order, Long> {}

4. Implement Services Add business logic in service classes like UserService.

5. Add GraphQL Controllers Use @QueryMapping and @MutationMapping annotations in UserController.

6. Define Schema
   Add schema.graphqls in src/main/resources:

   type Query {
       getUsers: [User]
       getUser(userId: ID!): User
   }
   type Mutation {
       createUser(name: String, email: String, password: String): User
       deleteUser(userId: ID!): Boolean
   }

7. Configure Application Enable GraphQL UI in application.properties:

   spring.graphql.graphiql.enabled=true

8. Run and Test

   • Start the application: mvn spring-boot:run.
   • Test GraphQL queries at /graphiql.

Example GraphQL Queries

• Get All Users:

  query {
      getUsers {
          userId
          name
          email
      }
  }

• Create a User:

  mutation {
      createUser(name: "John Doe", email: "[email protected]", password: "password123") {
          userId
          name
      }
  }