Spring Boot , Swagger - Unable to render this definition - spring-boot

Question

Spring boot
In my build.gradle:
plugins {
id 'org.springframework.boot' version '2.2.2.RELEASE'
id 'io.spring.dependency-management' version '1.0.8.RELEASE'
id 'java' // jar not work with JSP
//id 'war' // to use JSP
}
group = 'com.myproject'
version = '1.0.2'
sourceCompatibility = '1.8'
processResources {
filesMatching('application.yml') {
expand(project.properties)
}
}
repositories {
mavenCentral()
}
dependencies {
implementation 'com.google.code.gson:gson:2.7'
implementation 'com.h2database:h2'
implementation 'javax.servlet:jstl:1.2'
implementation 'org.springframework.boot:spring-boot-devtools'
implementation 'org.springframework.boot:spring-boot-starter'
implementation 'org.springframework.boot:spring-boot-starter-actuator'
implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
implementation 'org.springframework.boot:spring-boot-starter-jdbc'
implementation 'org.springframework.boot:spring-boot-starter-security'
implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'org.springframework.boot:spring-boot-starter-log4j2'
implementation 'com.fasterxml.jackson.dataformat:jackson-dataformat-yaml'
implementation 'com.squareup.okhttp3:logging-interceptor:3.8.0'
implementation('com.squareup.retrofit2:retrofit:2.4.0')
implementation('com.squareup.retrofit2:converter-gson:2.4.0')
compile group: 'io.springfox', name: 'springfox-swagger2', version: '2.9.2'
compile group: 'io.springfox', name: 'springfox-swagger-ui', version: '2.9.2'
testImplementation('org.springframework.boot:spring-boot-starter-test') {
exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
}
testImplementation 'org.junit.jupiter:junit-jupiter:5.5.2'
}
configurations {
all {
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
}
}
test {
useJUnitPlatform()
}
here application.yml
logging:
level:
org.hibernate.SQL: debug
# for Spring Actuator
management:
endpoints:
web:
exposure:
include: beans, env, info, health, metrics
server:
port: 8090
connection-timeout: 30000
spring:
application:
name: E-shop
version: ${version}
datasource:
url: jdbc:h2:file:./db/eshop.h2.db
username: sa
password:
driver-class-name: org.h2.Driver
jpa:
hibernate.ddl-auto: update
thymeleaf:
cache: false
enabled: true
prefix: classpath:/templates/
suffix: .html
h2: # default db. Open web page to H2 db -> http://localhost:8090/h2-console
console:
enabled: true
http:
converters:
preferred-json-mapper: gson
mvc:
view:
prefix: /WEB-INF/jsp/
suffix: .jsp
Here my security config:
#Configuration
#EnableWebSecurity
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
#Autowired
private DataSource dataSource; // get by Spring
#Override
public void configure(HttpSecurity http) throws Exception {
http
.headers().frameOptions().sameOrigin()
.and()
.authorizeRequests()
// Here, you are making the public directory on the classpath root available without authentication (e..g. for css files)
.antMatchers("/public/**", "/registration.html").permitAll()
.anyRequest().authenticated()
.and()
.formLogin()
.loginPage("/login.html")
.successHandler((request, response, authentication) -> new DefaultRedirectStrategy().sendRedirect(request, response, "/index"))
.failureUrl("/login-error.html")
.permitAll()
.and()
.logout()
.logoutSuccessHandler(new CustomLogoutSuccessHandler())
.permitAll();
}
// login by user from db
#Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
auth.jdbcAuthentication()
.dataSource(dataSource)
.passwordEncoder(NoOpPasswordEncoder.getInstance())
.usersByUsernameQuery("SELECT username, password, active FROM usr WHERE username=?")
.authoritiesByUsernameQuery("SELECT u.username, ur.role FROM usr u INNER JOIN user_roles ur ON u.id = ur.user_id WHERE u.username=?");
}
In my application:
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.core.task.TaskExecutor;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import springfox.documentation.swagger2.annotations.EnableSwagger2;
import java.util.Date;
#SpringBootApplication
#EnableAsync
#EnableSwagger2
public class EshopApplication {
Here my swagger config:
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;
#Configuration
#EnableSwagger2
public class SwaggerFoxConfig {
#Bean
public Docket api() {
return new Docket(DocumentationType.SWAGGER_2)
.select()
.apis(RequestHandlerSelectors.any())
.paths(PathSelectors.any())
.build();
}
}
But when I try to start Swagger on address:
http://127.0.0.1:8090/swagger-ui.html
I get error:
Unable to render this definition
The provided definition does not specify a valid version field.
Please indicate a valid Swagger or OpenAPI version field. Supported version fields are swagger: "2.0" and those that match openapi: 3.0.n (for example, openapi: 3.0.0).

Answer 1

Add the following bean to your code:
#Configuration
#EnableSwagger2
public class SpringFoxConfig {
#Bean
public Docket api() {
return new Docket(DocumentationType.SWAGGER_2)
.select()
.apis(RequestHandlerSelectors.any())
.paths(PathSelectors.any())
.build();
}
}

Answer 2

I was facing same problem. In my case, the problem was some mistake in serialization using jackson X gson.
What I did: I added a converter to gson in the Swagger config class.
#Bean
public GsonHttpMessageConverter gsonHttpMessageConverter() {
GsonHttpMessageConverter converter = new GsonHttpMessageConverter();
converter.setGson(gson());
return converter;
}
private Gson gson() {
final GsonBuilder builder = new GsonBuilder();
builder.registerTypeAdapter(Json.class, new SpringfoxJsonToGsonAdapter());
return builder.create();
}
public class SpringfoxJsonToGsonAdapter implements JsonSerializer<Json> {
#Override
public JsonElement serialize(Json json, Type type, JsonSerializationContext context) {
return JsonParser.parseString(json.value());
}
}