Why enterprise patterns matter in Spring Boot - See It in Action

Why Enterprise Patterns Matter in Spring Boot

📖 Scenario: You are building a simple Spring Boot application for a small company. The company wants to keep the code clean and easy to maintain as it grows. You will learn why using enterprise patterns helps in organizing the code well.

🎯 Goal: Create a basic Spring Boot project with a simple data model, a configuration setting, a service layer using a common enterprise pattern, and a controller to complete the application structure.

📋 What You'll Learn

Create a data model class representing a product

Add a configuration property for product availability threshold

Implement a service class using the Service pattern to filter products

Create a REST controller to expose the filtered products

💡 Why This Matters

🌍 Real World

Enterprise patterns are used in real Spring Boot applications to keep code clean and maintainable as projects grow.

💼 Career

Understanding these patterns is essential for backend developers working with Spring Boot in professional environments.

1

Create the Product data model

Create a Java class called Product with two private fields: name of type String and price of type double. Include a constructor to set these fields and getter methods for both.

Spring Boot

// Your code here to create Product class with name and price fields

Need a hint?

Think of Product as a simple box holding a name and price. Use private fields and public getters.

2

Add a configuration property for availability threshold

Create a double variable called availabilityThreshold in a configuration class called AppConfig and set it to 50.0.

Spring Boot

public class Product {
    private String name;
    private double price;

    public Product(String name, double price) {
        this.name = name;
        this.price = price;
    }

    public String getName() {
        return name;
    }

    public double getPrice() {
        return price;
    }
}

// Your code here to create AppConfig class with availabilityThreshold variable

Need a hint?

Use a public static final variable in AppConfig to hold the threshold value.

3

Implement the ProductService using the Service pattern

Create a class called ProductService with a method filterAvailableProducts that takes a List<Product> and returns a List<Product> containing only products with price greater than AppConfig.availabilityThreshold. Use a for loop and an if statement.

Spring Boot

public class Product {
    private String name;
    private double price;

    public Product(String name, double price) {
        this.name = name;
        this.price = price;
    }

    public String getName() {
        return name;
    }

    public double getPrice() {
        return price;
    }
}

public class AppConfig {
    public static final double availabilityThreshold = 50.0;
}

// Your code here to create ProductService class with filterAvailableProducts method

Need a hint?

Use a list to collect products that pass the price check and return it.

4

Create a REST controller to expose available products

Create a Spring Boot REST controller class called ProductController with a method getAvailableProducts mapped to /products/available. This method should return the result of ProductService.filterAvailableProducts when given a list of three products: "Pen", 10.0, "Notebook", 60.0, and "Backpack", 80.0. Use @RestController and @GetMapping annotations.

Spring Boot

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
import java.util.ArrayList;

// Your code here to create ProductController class with getAvailableProducts method

Need a hint?

Use Spring annotations to create a REST endpoint that returns filtered products.