OpenApi generator maven plugin - field validation (required) ignored - Spring

Question

I use openapi generator maven plugin to generate source code for a spring rest api. Here is the pom:

`<properties>
    <maven.compiler.source>17</maven.compiler.source>
    <maven.compiler.target>17</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

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

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

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.24</version>
        <scope>provided</scope>
    </dependency>

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

    <dependency>
        <groupId>org.openapitools</groupId>
        <artifactId>jackson-databind-nullable</artifactId>
        <version>0.2.4</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
        <version>3.0.0</version>
    </dependency>
    <dependency>
        <groupId>javax.annotation</groupId>
        <artifactId>javax.annotation-api</artifactId>
        <version>1.3.2</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
        <scope>provided</scope>
    </dependency>


</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
        <plugin>
            <groupId>org.openapitools</groupId>
            <artifactId>openapi-generator-maven-plugin</artifactId>
            <version>6.2.1</version>

            <executions>
                <execution>
                    <goals>
                        <goal>generate</goal>
                    </goals>
                    <configuration>
                        <inputSpec>${project.basedir}/openapi/openapi.yml</inputSpec>
                        <output>${project.basedir}/target/generated-sources/swagger</output>
                        <generatorName>spring</generatorName>
                        <library>spring-boot</library>
                        <generateApis>true</generateApis>
                        <generateModels>true</generateModels>
                        <modelPackage>...openapi.model</modelPackage>
                        <apiPackage>...openapi.api</apiPackage>
                        <supportingFilesToGenerate>ApiUtil.java</supportingFilesToGenerate>
                        <configOptions>
                            <delegatePattern>true</delegatePattern>
                            <useBeanValidation>true</useBeanValidation>
                        </configOptions>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>`

The code is generated fine, but despite i define a field required in the yml file, it doesnt have any effect - i can send a request with the required field being null and no error thrown. What do i have to do to make the constraints work (others like size limitation arent working either)? I can provide more code, but its simply the generated code with a very simple Delegate implementation.

Answer 1

I am not realy sure why, yet. But I had the same problem and I solved it adding the following dependency:

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-validation</artifactId>
        <version>3.0.2</version>
    </dependency>

It seems that in there it has this dependency that "makes the validation avaliable":

    <dependency>
        <groupId>org.hibernate.validator</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>6.2.0.Final</version>
    </dependency>

comparing your pom to mine, I am also ussing this 2 dependencies too:

    <dependency>
        <groupId>io.swagger.parser.v3</groupId>
        <artifactId>swagger-parser</artifactId>
        <version>2.1.8</version>
    </dependency>

    <dependency>
        <groupId>org.openapitools</groupId>
        <artifactId>jackson-databind-nullable</artifactId>
        <version>0.2.4</version>
    </dependency>

Give it a try, I hope it solves your problem too.

Let me know if it works!!