Spring Boot Validation is not working with javax.validation - spring

Question

I am working on a Spring Boot project and I am currently trying to implement validation. For example, I have the following class:
package abcdef.mypackage
import java.util.*
import javax.persistence.Column
import javax.persistence.Entity
import javax.persistence.GeneratedValue
import javax.persistence.Id
import javax.validation.constraints.Email
import javax.validation.constraints.NotBlank
#Entity
class User (
#Id
#GeneratedValue
var id: Long,
#Column(name="username", unique = true, nullable = false)
#NotBlank
var username: String,
#Column(name="password", unique = false, nullable = false)
var password: String,
#Column(name="firstname", unique = false, nullable = false)
#NotBlank
var firstname: String,
#Column(name="lastname", unique = false, nullable = false)
#NotBlank
var lastname: String,
#Column(name = "birthdate", unique = false, nullable = true)
var birthdate: Date? = null,
#Column(name="email", unique = true, nullable = false)
#Email
var email: String,
#Column(name="phone", unique = true, nullable = false)
var phone: String,
)
You can see, that I have annotated all fields with the validations I want to have. Incoming requests are handled by the following controller class:
package abcdef.mypackage
import org.springframework.http.ResponseEntity
import org.springframework.validation.BindingResult
import org.springframework.validation.annotation.Validated
import org.springframework.web.bind.annotation.*
import org.springframework.web.server.ResponseStatusException
import javax.validation.Valid
#RestController
#RequestMapping("/api/v1/users/")
#Validated
class UserResource(val service: UserService) {
#PostMapping("/register")
#Validated
fun post(#Valid #RequestBody user: User, result: BindingResult) : ResponseEntity<Unit> {
if (result.hasErrors()) {
return ResponseEntity.badRequest().build()
}
try {
service.post(user)
} catch (e: Exception) {
return ResponseEntity.badRequest().build()
}
return ResponseEntity.ok().build()
}
}
When I now make a request with for example a blank username value, Spring Boot still accepts it and stores into the database. I have found some questions (and answers) on StackOverflow about missing dependencies, but I included all of those. You can take a look at my dependecies here:
<dependencies>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-reflect</artifactId>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-stdlib-jdk8</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
<dependency>
<groupId>org.mariadb.jdbc</groupId>
<artifactId>mariadb-java-client</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
</dependency>
</dependencies>
I have no Idea what to do to get this validation working... I cannot see any issue in my dependencies. I also tried some variations with the usage of #Valid and #Validated but nothing worked for me.
I hope somebody sees my mistake. Thanks a lot!

Answer 1

Example: recommend data class + #field:NotBlank and not need #Validated