Spring Boot Mastery #10: DTO Validation Explained | Bean Validation | @NotNull, @Email Explained
Welcome to Spring Boot Mastery #10 by Hosiyar.com.
This is an important milestone in our Spring Boot series.
Since this is video number 10, we will first take a quick recap of everything we have covered so far in this playlist. In the first few minutes, we will revise the complete journey: Spring Boot overview, project setup, first API, internal working, REST APIs, layered architecture, database integration, CRUD project, clean code refactoring, DTOs, and Java records.
After the recap, we will move into one of the most important concepts in real backend development:
Validation
In the previous videos, we improved our Course Management System project using DTOs. But now comes a serious problem.
What if the client sends invalid data?
For example:
Empty course name
Invalid price
Negative duration
Missing required fields
Invalid email format
Too short or too long values
If we do not validate the incoming request, this invalid data can directly enter our application and even get saved into the database.
And that is not acceptable in real-world applications.
So in this video, we will first understand the problem of invalid data. We will send incorrect data through the API and observe how it affects the database when validation is not applied.
Then we will implement validation properly in our Spring Boot project.
We will add the required validation dependency in pom.xml, apply validation annotations in our DTO class, and use @Valid in the controller to activate validation for incoming request data.
We will also discuss popular Bean Validation annotations and understand where they are used.
Updated code: https://github.com/deep473/cms/tree/v...
In this video, we will cover:
✅ Quick recap of the complete Spring Boot series so far
✅ Recap of Course Management System project
✅ Why validation is needed
✅ Problem with accepting invalid API request data
✅ How invalid data can affect the database
✅ What is Bean Validation?
✅ Adding validation dependency in pom.xml
✅ Applying validation annotations in DTO
✅ Using @Valid in Controller
✅ Validating request body data
✅ Common validation annotations
✅ Testing validation using Postman
✅ How validation improves API quality
✅ Why validation is important in real projects
Popular Validation Annotations Discussed
In this video, we will discuss commonly used validation annotations such as:
✅ @NotNull
✅ @NotBlank
✅ @NotEmpty
✅ @Size
✅ @Min
✅ @Max
✅ @Email
✅ @Pattern
✅ @Positive
✅ @PositiveOrZero
These annotations help us define rules for incoming request data so that our application accepts only valid input.
By the end of this video:
You will understand why validation is required in Spring Boot APIs and how to validate DTOs before saving data into the database.
You will also understand how Bean Validation works with DTOs, how @Valid activates validation in the controller, and how validation annotations help us protect our application from bad input.
This video makes our Course Management System project more reliable and closer to real-world backend development standards.
Short Description
In this video, we continue our Spring Boot Course Management System project and implement DTO validation using Bean Validation. Since this is video #10, we first revise the complete series so far, then understand the problem of invalid data entering the database. We add the validation dependency in pom.xml, apply validation annotations in DTO, use @Valid in the controller, and test validation using Postman.
#SpringBoot #BeanValidation #DTOValidation #JavaBackendDevelopment #SpringBootProject #RESTAPI #CleanCode #HosiyarDotCom