How to Use @Email Annotation in Spring Boot for Validation

In Spring Boot, use the @Email annotation on a String field to validate that it contains a valid email address format. Combine it with @Valid in your controller or service to trigger validation automatically.

Syntax

The @Email annotation is placed on a String field to check if the value is a valid email format. It is part of the javax.validation.constraints package. You can customize the error message with the message attribute.

Example parts:

• @Email: Validates email format.
• message: Custom error message shown if validation fails.
• @NotBlank: Often combined to ensure the field is not empty.

java

import javax.validation.constraints.Email;
import javax.validation.constraints.NotBlank;

public class User {
    @NotBlank(message = "Email is required")
    @Email(message = "Invalid email format")
    private String email;

    // getters and setters
}

Example

This example shows a Spring Boot REST controller that accepts a user object with an email field. The @Email annotation validates the email format automatically when the request is received. If the email is invalid, Spring Boot returns a 400 Bad Request with the validation error.

java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.http.ResponseEntity;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;
import javax.validation.constraints.Email;
import javax.validation.constraints.NotBlank;

@SpringBootApplication
public class EmailValidationApp {
    public static void main(String[] args) {
        SpringApplication.run(EmailValidationApp.class, args);
    }
}

@RestController
@Validated
class UserController {
    @PostMapping("/users")
    public ResponseEntity<String> createUser(@Valid @RequestBody User user) {
        return ResponseEntity.ok("User email is valid: " + user.getEmail());
    }
}

class User {
    @NotBlank(message = "Email is required")
    @Email(message = "Invalid email format")
    private String email;

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

Output

POST /users with body {"email":"[e-mail]"} returns 200 OK with message "User email is valid: [e-mail]"

POST /users with body {"email":"invalid-email"} returns 400 Bad Request with validation error "Invalid email format"

Common Pitfalls

• Not using @Valid on the controller method parameter will skip validation.
• Using @Email alone without @NotBlank allows empty strings, which may not be desired.
• Custom error messages must be set on @Email to provide clear feedback.
• Validation errors must be handled or Spring Boot will return default error responses.

java

/* Wrong: Missing @Valid, validation won't trigger */
@PostMapping("/users")
public ResponseEntity<String> createUser(@RequestBody User user) {
    return ResponseEntity.ok("User email is valid: " + user.getEmail());
}

/* Right: Add @Valid to trigger validation */
@PostMapping("/users")
public ResponseEntity<String> createUser(@Valid @RequestBody User user) {
    return ResponseEntity.ok("User email is valid: " + user.getEmail());
}

Quick Reference

Summary tips for using @Email in Spring Boot:

• Place @Email on String fields to validate email format.
• Combine with @NotBlank to prevent empty values.
• Use @Valid on controller method parameters to enable validation.
• Customize error messages with the message attribute.
• Handle validation errors gracefully in your application.

Key Takeaways

Use @Email on String fields to validate email format in Spring Boot.

Always add @Valid on controller parameters to trigger validation.

Combine @Email with @NotBlank to avoid empty email values.

Customize error messages with the message attribute for clarity.

Handle validation errors to provide user-friendly feedback.