Chapter 1: Introduction to E-Commerce Order Placement

In this tutorial, we will explore how to integrate the Place Order functionality into our e-commerce application using Spring Boot. Our goal is to create an order and display the user's order history effectively.

We are developing a comprehensive e-commerce application from the ground up. The frontend leverages Vue.js, while the backend is powered by Java with Spring Boot. You can refer to the initial frontend tutorial of this series for more context.

The ability to place orders is crucial for any e-commerce platform, allowing users to purchase their desired products. Initially, we will focus on building the backend API with Spring Boot, followed by utilizing this API in the frontend of our website in subsequent tutorials.

For a deeper understanding, you can refer to the tutorial where we previously implemented the checkout feature. You can also test the API through the provided Swagger link, which contains the cart API located in the order-controller section (ensure to run the code locally first).

Swagger API Link: [Swagger API](#)

You can find the complete code on GitHub.

Pre-requisites

To follow along, you should have:

• Knowledge of Java, OOP, and the Spring Boot Framework
• Java Development Kit (JDK)
• IntelliJ IDEA Ultimate (Recommended)
• MySQL/MariaDB Database
• A reliable web browser (Chrome is recommended)

Project Structure

We will be developing the following API endpoints:

• placeOrder (/order/add): A POST method responsible for saving user orders.
• getAllOrders (/order/): A GET method that retrieves all orders associated with a specific user, requiring only the user's token as a parameter.

Chapter 2: Model and Table Design

Before we dive into coding, it's essential to consider our model and table design. We will need two linked tables: Order and OrderItem.

1. Order Table: This will include attributes such as:
   • id (primary key)
   • user_id (foreign key)
   • created_date
   • session_id (the payment session ID we generated)
   • total_price

The user_id will be fetched from the users table. For further details on the session ID, please refer to our previous tutorial on the checkout session.

2. Order Items Table: This table will hold the products corresponding to a specific order. We will establish a relationship between these two tables, using the primary key id from the Order table as a foreign key in the OrderItems table. The attributes for the order items table will include:
   • order_item_id
   • created_date
   • price
   • product_id (foreign key)
   • quantity
   • order_id (foreign key)

The product_id will be sourced from the products table.

Table Relationships

• The relationship between the Order table and OrderItems table is one-to-many. Each entry in the Order table can relate to multiple items in the OrderItems table.
• The Order and User tables share a many-to-one relationship; multiple orders can be linked to a single user.
• The OrderItems and Products tables have a one-to-one relationship since each item in the OrderItems table corresponds to a unique entry in the Products table.

Repository Creation

Next, we will create two Java files in the repository package: OrderRepository.java and OrderItemsRepository.java.

1. OrderRepository.java: This interface will extend the JPARepository, automatically providing CRUD methods. We will define a custom method findAllByUserIdOrderByCreatedDateDesc to retrieve a user's orders sorted by the creation date.
2. OrderItemsRepository.java: This interface will be created without any specific methods, as we will utilize it in the service class later.

Data Transfer Objects (DTO)

In the dto package, create a subpackage named order and include the following files:

• OrderDto.java: A placeholder object for the Order model with fields for id and userId.
• OrderItemsDto.java: Similar to OrderDto, prepared for future use.
• PlaceOrderDto.java: Contains fields id, userId, and totalCost, which will be used to save orders in the Order table.

Service Implementation

Now, we will develop the Service class to interact with the Order and OrderItems tables. This will call the methods defined in the OrderRepository interface, implementing the business logic.

1. OrderItemsService: This service will contain a method to save an item in a specific order.
2. OrderService: This class will handle logic for placing orders and retrieving order details.

• placeOrder: This method accepts the PlaceOrderDto and retrieves the order ID from the saveOrder method. It utilizes the cartService to fetch cart items and saves them in the OrderItems table, subsequently clearing the cart.

  • saveOrder: This method initializes the order object, saves it in the Order table, and returns the ID for use in OrderItems.
  • listOrders: Accepts the user ID as a parameter and returns all corresponding orders.

Controller Development

In the controller package, create the OrderController.java file, annotated with @RestController. This class will implement the APIs we defined in the OrderService class.

1. placeOrder: This method will accept the token and session ID as parameters and throw exceptions for invalid users or nonexistent products.
2. getOrders: This method will retrieve a user's order history, throwing an exception for invalid users.

Congratulations! You have successfully implemented the Place Order feature in your e-commerce application using Spring Boot. In the next tutorial, we will focus on the frontend integration using Vue.js, so stay tuned!

Chapter 3: Video Resources

To further enhance your understanding, check out these tutorial videos:

This video demonstrates how to place an order in an e-commerce application using Spring Boot.

In this episode, we will build an e-commerce store with a Spring Boot backend.