javax.validation.constraints does not work with Spring web

Question

Here is my controller:

import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.NotNull;

@Slf4j
@RestController
@RequestMapping("/auth-api")
public class AuthController {

    @PostMapping("/register")
    public RequestResultJSON<String> register(@RequestParam @NotEmpty String username,
                                              @RequestParam @NotEmpty String password,
                                              @RequestParam @NotEmpty  String passwordConfirm);

And i use this dependencies in my pom.xml file

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.3.0.RELEASE</version>
</parent>

<dependencies>
    <dependency>
        <groupId>javax.validation</groupId>
        <artifactId>validation-api</artifactId>
        <version>2.0.1.Final</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

When I make a post request I expect that method execution will not happen, but it happens with incorrect parameters

Request: http://localhost:8080/auth-api/register?username&password&passwordConfirm

And register method execute with username="", password="", passwordConfirm=""

Answer 1

you need to add @Validated annotation on your controller, which marks it to be validated.

@Slf4j
@Validated
@RestController
@RequestMapping("/auth-api")
public class AuthController {
  // your code
}

Additionally, you have to make sure you have one validator implementation like hibernate-validator in your classpath.

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.0.10.Final</version>
</dependency>

If not already present, you can add above dependency in your pom.xml or any other suitable version from here