@Email and @Pattern in Spring Boot - Mini Project: Build & Apply

Validating User Email and Username with @Email and @Pattern in Spring Boot

📖 Scenario: You are building a simple Spring Boot application to register users. You want to make sure the email addresses are valid and usernames follow specific rules.

🎯 Goal: Create a User class with fields email and username. Use @Email to validate the email format and @Pattern to ensure the username contains only letters and numbers, with length between 3 and 10 characters.

📋 What You'll Learn

Create a User class with email and username fields

Use @Email annotation on the email field

Use @Pattern annotation on the username field with regex ^[a-zA-Z0-9]{3,10}$

Include getter and setter methods for both fields

💡 Why This Matters

🌍 Real World

Validating user input like email and username is common in web applications to ensure data quality and security.

💼 Career

Understanding validation annotations in Spring Boot is essential for backend developers working on user registration and data validation.

1

Create the User class with email and username fields

Create a public class called User with two private String fields: email and username.

Spring Boot

public class User {
    // Your code here
}

Need a hint?

Define the class and declare the two fields exactly as email and username.

2

Add @Email annotation to the email field

Add the @Email annotation above the email field in the User class. Also import jakarta.validation.constraints.Email.

Spring Boot

import jakarta.validation.constraints.Email;

public class User {
    // Add @Email annotation here
    private String email;
    private String username;
}

Need a hint?

Place @Email directly above the email field.

3

Add @Pattern annotation to the username field

Add the @Pattern annotation above the username field with the regex "^[a-zA-Z0-9]{3,10}$". Import jakarta.validation.constraints.Pattern.

Spring Boot

import jakarta.validation.constraints.Pattern;

public class User {
    @Email
    private String email;
    // Add @Pattern annotation here
    private String username;
}

Need a hint?

Use the exact regex and place @Pattern above username.

4

Add getter and setter methods for email and username

Add public getter and setter methods for both email and username fields in the User class.

Spring Boot

public String getEmail() {
    // Your code here
}

public void setEmail(String email) {
    // Your code here
}

public String getUsername() {
    // Your code here
}

public void setUsername(String username) {
    // Your code here
}

Need a hint?

Write standard getter and setter methods for both fields.