Spring Boot 4 Microservices & REST APIs · Aula

Funções sem servidor com Spring Cloud

Explore a criação e a implantação de funções sem servidor usando o Spring Cloud Function.

Funções sem servidor com Spring Cloud é uma aula grátis de Spring Boot 4 Microservices & REST APIs no CoddyKit. Esta é a aula 2 de 3. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de Spring Boot 4 Microservices & REST APIs, e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de Spring Boot 4 Microservices & REST APIs inclui 3 aulas no total.

Partes desta aula ainda não foram traduzidas e aparecem em inglês.

What are Serverless Functions?

Serverless functions (also known as Functions as a Service or FaaS) are small, single-purpose pieces of code that run in response to events, without you having to manage any servers.

You only pay for the compute time consumed.
No server provisioning or scaling to worry about.
Focus purely on your code logic.

Introducing Spring Cloud Function

Spring Cloud Function is a framework that helps you write business logic as Java java.util.function types (Supplier, Function, Consumer).

The magic? You write your function once, and Spring Cloud Function makes it deployable across different serverless platforms like AWS Lambda, Azure Functions, or Google Cloud Functions, with minimal changes.

Supplier: No Input, Just Output

A Supplier is a function that takes no arguments but produces a result. Think of it as a data source or a generator.

It implements java.util.function.Supplier<T>.
It has a single method: T get().
Useful for polling, scheduled tasks, or generating initial data.

Your First Supplier Function

This example shows a simple Supplier that returns a greeting message. The @Bean annotation exposes it as a Spring Cloud Function.

Try running it to see the output!

import java.util.function.Supplier;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.ConfigurableApplicationContext;

@SpringBootApplication
public class SupplierApp {

    public static void main(String[] args) {
        // Run Spring Boot application context
        ConfigurableApplicationContext context = SpringApplication.run(SupplierApp.class, args);
        // Get the supplier bean and invoke its 'get' method
        Supplier<String> helloSupplier = context.getBean("helloSupplier", Supplier.class);
        System.out.println(helloSupplier.get());
        context.close(); // Clean up context
    }

    @Bean
    public Supplier<String> helloSupplier() {
        return () -> "Hello from CoddyKit Serverless!";
    }
}

Function: Input to Output

A Function is a mapping from one type to another. It takes an argument and produces a result.

It implements java.util.function.Function<T, R>.
It has a single method: R apply(T t).
Perfect for data transformation, processing requests, or applying business logic.

Transform Data with a Function

Here, our upperCaseFunction takes a String and returns its uppercase version. This demonstrates a simple data transformation.

Run the code and observe how the input changes!

import java.util.function.Function;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.ConfigurableApplicationContext;

@SpringBootApplication
public class FunctionApp {

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(FunctionApp.class, args);
        Function<String, String> upperCaseFunction = context.getBean("upperCaseFunction", Function.class);
        String input = "coddykit serverless";
        String output = upperCaseFunction.apply(input);
        System.out.println("Input: " + input);
        System.out.println("Output: " + output);
        context.close();
    }

    @Bean
    public Function<String, String> upperCaseFunction() {
        return value -> value.toUpperCase();
    }
}

Consumer: Input, No Output

A Consumer is a function that takes an argument but produces no result. It's used for performing an action or side effect.

It implements java.util.function.Consumer<T>.
It has a single method: void accept(T t).
Ideal for logging, saving data, sending notifications, or triggering other processes.

Process Data with a Consumer

This printerConsumer takes a String and simply prints it to the console. It consumes the data without returning anything.

See how the message is processed!

import java.util.function.Consumer;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.ConfigurableApplicationContext;

@SpringBootApplication
public class ConsumerApp {

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(ConsumerApp.class, args);
        Consumer<String> printerConsumer = context.getBean("printerConsumer", Consumer.class);
        String message = "Processing complete for this event!";
        System.out.println("Consuming message...");
        printerConsumer.accept(message);
        context.close();
    }

    @Bean
    public Consumer<String> printerConsumer() {
        return value -> System.out.println("Received and processed: " + value);
    }
}

Deployment Agnostic Power

The core strength of Spring Cloud Function is its deployment agnosticism. You write your function once using standard Java interfaces, and the framework provides adapters to run it on various serverless platforms.

This means you're not locked into a specific cloud provider's API, making your code more portable and future-proof.

Function Type Check

Which type of Spring Cloud Function is designed to take an input and produce a transformed output?

Recap: Serverless & Spring Cloud Function

We've explored serverless functions and how Spring Cloud Function enables you to write portable business logic.

Serverless means focusing on code, not infrastructure.
Spring Cloud Function uses Supplier, Function, and Consumer interfaces.
These functions can be deployed to various FaaS platforms, offering great flexibility.

This approach simplifies development and increases the portability of your microservices.

Perguntas Frequentes

A aula “Funções sem servidor com Spring Cloud” é grátis?

Sim — o texto completo de “Funções sem servidor com Spring Cloud” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de Spring Boot 4 Microservices & REST APIs, atualize para CoddyKit PRO. O curso de Spring Boot 4 Microservices & REST APIs inclui 3 aulas no total.

O que vou aprender em “Funções sem servidor com Spring Cloud”?

Explore a criação e a implantação de funções sem servidor usando o Spring Cloud Function. Você pratica Spring Boot 4 Microservices & REST APIs com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.

Preciso ter experiência prévia para começar Spring Boot 4 Microservices & REST APIs?

Nenhuma experiência prévia é necessária. Spring Boot 4 Microservices & REST APIs no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 2 de 3.

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