Spring Boot MongoDB CRUD Example

What is SpringBoot?

Spring Boot is a Java-based open-source framework that simplifies the development of stand-alone, production-grade applications. It provides a comprehensive platform for creating Java applications with minimal configuration and boilerplate code. Spring Boot incorporates the powerful features of the Spring framework and embeds an embedded server, allowing developers to create self-contained applications that can be deployed independently. It promotes convention over configuration, enabling rapid application development and reducing the setup time. Spring Boot supports various technologies such as RESTful web services, data access, security, messaging, and more, making it a popular choice for building scalable and efficient Java applications.

What is Mongodb?

MongoDB is a document-oriented NoSQL database that provides a flexible and scalable approach to storing and managing data. It diverges from traditional relational databases by using a JSON-like document model, allowing for dynamic and schema-less data structures. MongoDB is designed for high performance, horizontal scalability, and ease of use. It supports automatic sharding, replication, and load balancing, making it suitable for handling large volumes of data and distributed deployments. It offers rich querying capabilities, including powerful indexing and aggregation frameworks. MongoDB is widely adopted in modern web applications, big data, and real-time analytics scenarios, providing developers with a robust and scalable database solution.

What is MongoRepository?

MongoRepository is a part of the Spring Data MongoDB framework, which provides a higher-level abstraction for interacting with MongoDB databases in Java applications. It is an interface-based repository that offers a set of pre-defined methods for performing common database operations, such as CRUD (Create, Read, Update, Delete) operations, on MongoDB collections. MongoRepository simplifies the process of writing data access code by eliminating the need for manual implementation of low-level database operations. It also supports dynamic query generation based on method names and parameter types, reducing the need for writing custom queries. By extending MongoRepository, developers can easily integrate MongoDB with their Spring Boot applications.

Some key features of MongoRepository include:

• CRUD operations:
  MongoRepository provides methods for creating, reading, updating, and deleting documents in a MongoDB collection. It includes methods like save(), findById(), findAll(), deleteById(), etc.
• Query generation:
  MongoRepository generates MongoDB queries automatically based on method names. For example, if a method is named findByFirstName(), it will generate a query to find documents with a specific first name.
• Pagination and sorting:
  MongoRepository supports pagination and sorting of query results. It provides methods like findAll(Pageable pageable) and findAll(Sort sort) to retrieve data in a paginated or sorted manner.
• Custom queries:
  Besides automatically generated queries, MongoRepository also allows developers to define custom queries using annotations or Query DSL (Domain Specific Language).
• Integration with Spring Data features:
  MongoRepository seamlessly integrates with other Spring Data features, such as support for transactions, auditing, and caching.

What are CRUD operations?

CRUD operations refer to the basic operations performed on data in a persistent storage system, such as a database. CRUD is an acronym that stands for Create, Read, Update, and Delete.

• Create:
  The create operation involves inserting or adding new data to the database, creating a new record or document.
• Read:
  The read operation retrieves or reads data from the database. It allows retrieving specific records or documents based on specified criteria or fetching all data.
• Update:
  The update operation modifies or changes existing data in the database. It involves updating specific fields or properties of a record or document.
• Delete:
  The delete operation removes or deletes data from the database. It involves removing specific records or documents based on specified criteria.

These four operations form the basic building blocks of data manipulation in most database systems and are essential for performing various operations on data in applications.

Create a Library Project

To create a library project using Spring Boot and MongoDB, follow these steps:

Prerequisites

1. MongoDB Atlas Account:
   Sign up for a MongoDB Atlas account, which will provide us with a managed MongoDB database. This will allow us to store and retrieve our book data.
2. Install Java and Springboot:
   Install Java and Spring Boot on your development machine. Java is the programming language, and Spring Boot is the framework we will use to build our library project.

Project Setup

Let's start by setting up our project and configuring the necessary classes, interfaces, and repositories.

• Create a new Spring Boot Project:
  Use your preferred Integrated Development Environment (IDE) to create a new Spring Boot project. This can be done using tools like Spring Initializr or directly within your IDE.
• Configure MongoDB Atlas:
  In your MongoDB Atlas account, create a new cluster and obtain the connection details (connection string). This information will be used to establish a connection between our Spring Boot application and the MongoDB database.
• Configure Spring Boot:
  In your Spring Boot project, update the application.properties or application.yml file with the MongoDB connection details. This includes the database URL, username, password, and other necessary configurations.
• Create Entity Class:
  Define a Book class that represents our book entity. This class should include attributes such as id, title, author, isbn, and any other relevant information for a book.

• Create Repository Interface:
  Create a repository interface, such as BookRepository, that extends the MongoRepository interface provided by Spring Data MongoDB. This interface will provide us with built-in methods for performing CRUD operations on our Book entity.

Create a book in Mongodb using Springboot

Now that we have our project set up, let's demonstrate how to create a book in MongoDB using Spring Boot. We will also show the results in MongoDB Atlas.

Save
To save a single book, you can use the save() method provided by the BookRepository. Create a new instance of the Book class, set its attributes, and call the save() method to persist it to the database.

Saveall
To save multiple books at once, use the saveAll() method provided by the BookRepository. Pass a list of Book objects to this method, and it will save all the books in a single batch operation.

Insert
Alternatively, you can use the insert() method provided by the BookRepository to insert a book into the database. This method differs from save() in that it only performs an insert operation and does not perform an update if the book already exists.

Read Books from Mongodb Using Springboot

Now let's explore how to read books from MongoDB using Spring Boot. We will cover two common operations: retrieving all books and finding a book by its ID.

Findall
To retrieve all books from the database, use the findAll() method provided by the BookRepository. This method returns a list of all books present in the collection.

Findbyid
If you have the ID of a specific book, you can use the findById() method provided by the BookRepository to retrieve that particular book from the database.

Update a Book in Mongodb using Springboot

To update a book in MongoDB using Spring Boot, follow these steps:

Retrieve
Use the findById() method to find the book you want to update and store it in a variable.

Delete a Book in Mongodb using Springboot

To delete a book from MongoDB using Spring Boot, perform the following steps:

delete
Use the findById() method to find the book you want to delete and store it in a variable.