GraphQL APIs with Spring Boot · 강의

변이에 입력 타입 활용하기

재사용 가능한 입력 타입을 정의해 변이 인자를 간소화하고 API 호출을 더 깔끔하고 체계적으로 구성합니다.

변이에 입력 타입 활용하기은(는) CoddyKit의 무료 GraphQL APIs with Spring Boot 강의입니다. 이것은 4개 중 3번째 강의입니다. 아래에서 전체 강의를 무료로 읽을 수 있으며, 내장 코드 에디터와 24/7 AI 튜터와 함께 브라우저에서 직접 실습할 수 있습니다. 이 강의는 GraphQL APIs with Spring Boot 학습 경로의 일부이며, 진행 상황이 웹과 CoddyKit 앱에 동기화됩니다. GraphQL APIs with Spring Boot 강의에는 총 4개의 강의가 포함되어 있습니다.

이 강의의 일부는 아직 번역되지 않았으며 영어로 표시됩니다.

Long Mutation Arguments?

When building GraphQL mutations, you often need to pass several pieces of data to create or update an entity. Think about creating a new user or a product.

Passing each field as a separate argument can make your mutation signatures quite long and hard to manage, leading to less readable and maintainable code.

Meet GraphQL Input Types

Input types are special object types in GraphQL used specifically as arguments for mutations (or sometimes queries). They allow you to group related fields into a single, structured object.

This makes your mutation definitions cleaner and more organized, similar to how a DTO (Data Transfer Object) works in traditional REST APIs.

Input Type Syntax (SDL)

Defining an input type in your GraphQL Schema Definition Language (SDL) is straightforward. You use the input keyword instead of type.

Input types can only contain scalar types, enums, or other input types as their fields. They cannot contain output object types, interfaces, or union types.

input CreateProductInput {
  name: String!
  description: String
  price: Float!
  category: String
}

The Problem: Many Arguments

Consider a mutation to create a new product. Without an input type, you might define it like this:

Notice how the argument list can become long and repetitive, especially if you have many fields. This can be cumbersome to write and read.

type Mutation {
  createProduct(
    name: String!,
    description: String,
    price: Float!,
    category: String
  ): Product
}

The Solution: Clean Mutations

By using our CreateProductInput, the mutation signature becomes much cleaner and easier to read. All related input fields are now encapsulated within a single argument.

This improves clarity and reduces clutter in your schema.

type Mutation {
  createProduct(input: CreateProductInput!): Product
}

input CreateProductInput {
  name: String!
  description: String
  price: Float!
  category: String
}

Spring Boot DTO for Input

In your Spring Boot application, you'll represent your GraphQL input types as simple Java classes. These act as Data Transfer Objects (DTOs) that Spring's GraphQL integration can automatically map for you.

Ensure the field names in your Java class match your SDL input type for seamless mapping.

package com.coddykit.graphql;

public class CreateProductInput {
    private String name;
    private String description;
    private float price;
    private String category;

    // Getters and Setters (omitted for brevity)
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    // ... other getters/setters
}

Using Input in Resolver

Now, let's see how your GraphQL resolver method in Spring Boot will use this CreateProductInput DTO. Instead of multiple @Argument annotations, you'll have just one for your input object.

This makes the resolver method signature much cleaner and easier to manage, especially with many input fields.

package com.coddykit.graphql;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.graphql.data.method.annotation.Argument;
import org.springframework.graphql.data.method.annotation.MutationMapping;
import org.springframework.stereotype.Controller;

// Dummy Product class for example return type
class Product {
    String id; String name; public Product(String id, String name) { this.id = id; this.name = name; } 
    public String getId() { return id; } public String getName() { return name; }
}

// Input DTO from previous scene
class CreateProductInput {
    private String name; private String description; private float price; private String category;
    public String getName() { return name; } public void setName(String name) { this.name = name; }
    public String getDescription() { return description; } public void setDescription(String description) { this.description = description; }
    public float getPrice() { return price; } public void setPrice(float price) { this.price = price; }
    public String getCategory() { return category; } public void setCategory(String category) { this.category = category; }
}

@SpringBootApplication
@Controller
public class Main {

    public static void main(String[] args) {
        // This would start a Spring Boot web server
        // SpringApplication.run(Main.class, args);
        System.out.println("Application context started (conceptually).");
    }

    private static long productIdCounter = 1;

    @MutationMapping
    public Product createProduct(@Argument CreateProductInput input) {
        System.out.println("Creating product: " + input.getName());
        // In a real application, you'd save this to a database
        String newId = "prod-" + productIdCounter++;
        return new Product(newId, input.getName());
    }
}

Why Use Input Types?

Input types offer several significant advantages for your GraphQL API design:

Readability: Mutation signatures become much shorter and clearer.
Reusability: The same input type can often be used for both creation and update mutations, reducing schema duplication.
Validation: It's easier to apply validation logic to a single, consolidated input object.
Extensibility: Adding new optional fields to an input type doesn't break existing clients, as they can simply ignore the new fields.

Complex Data with Nested Inputs

Input types can also contain other input types, allowing you to model complex, hierarchical data for your mutations. This is very powerful for structured data submission.

For example, when creating an order, you might need to include customer details and a list of items, each with its own properties, all within a single input object.

input AddressInput {
  street: String!
  city: String!
  zipCode: String
}

input CustomerInput {
  name: String!
  email: String!
  shippingAddress: AddressInput
}

input CreateOrderInput {
  customer: CustomerInput!
  items: [OrderItemInput!]!
}

input OrderItemInput {
  productId: ID!
  quantity: Int!
}

Input Types Check

You've learned about GraphQL Input Types and their benefits. Let's test your understanding!

Recap: Input Types Mastered!

Great job! In this lesson, you mastered GraphQL Input Types. You learned how they streamline mutation arguments, making your API cleaner and more maintainable.

We saw how to define input types in SDL using the input keyword.
Implemented them in Spring Boot resolvers by using DTOs.
And explored their key benefits like improved readability, reusability, and easier validation.

These are essential for building robust and user-friendly GraphQL APIs! Keep practicing!

자주 묻는 질문

“변이에 입력 타입 활용하기” 강의는 무료인가요?

네 — “변이에 입력 타입 활용하기” 전체 내용을 이 웹사이트에서 무료로 읽을 수 있습니다. 인터랙티브하게 실습하려면(내장 코드 에디터와 24/7 AI 튜터), CoddyKit PRO로 업그레이드하면 GraphQL APIs with Spring Boot 강의 전체를 잠금 해제할 수 있습니다. GraphQL APIs with Spring Boot 강의에는 총 4개의 강의가 포함되어 있습니다.

“변이에 입력 타입 활용하기”에서 뭘 배우나요?

재사용 가능한 입력 타입을 정의해 변이 인자를 간소화하고 API 호출을 더 깔끔하고 체계적으로 구성합니다. 브라우저에서 직접 실행하는 실습 코드로 GraphQL APIs with Spring Boot을(를) 배우며, 24/7 AI 튜터가 강의를 진행하면서 질문에 답변해줍니다.

GraphQL APIs with Spring Boot을(를) 시작하는 데 경험이 필요한가요?

사전 경험은 필요하지 않습니다. CoddyKit의 GraphQL APIs with Spring Boot은(는) 초급자부터 고급 학습자까지를 위해 구성되어 있으므로, 여기서 시작하거나 처음부터 시작할 수 있으며 자신의 속도대로 진행할 수 있습니다. 이것은 4개 중 3번째 강의입니다.

“변이에 입력 타입 활용하기” 강의는 얼마나 걸리나요?

대부분의 CoddyKit 강의는 약 5~10분이 소요됩니다. 각 강의는 간결하고 인터랙티브하여 꾸준한 진행이 가능하며, 웹과 앱에서 중단한 부분부터 바로 시작할 수 있습니다.

이 GraphQL APIs with Spring Boot 강의에서 코드를 작성하고 실행할 수 있나요?

네. 모든 GraphQL APIs with Spring Boot 강의에는 내장 코드 에디터가 포함되어 있으므로, 브라우저에서 바로 실제 코드를 작성하고 실행한 후 즉시 AI 피드백을 받을 수 있습니다 — 로컬 설정이 필요 없습니다.

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