Why HATEOAS starts creating issue for spring-boot version >= 2.2.x during startup with Swagger 2.x?

Question

I moved my project from spring-boot 2.1.9 to 2.2.0.

While starting the project, I am facing the below error messages.

Caused by: org.sprin         


        

Answer 1

I am using springdoc-openapi and after having encountered this problem similar to the one mentioned here:

Description:

Parameter 0 of method linkDiscoverers in org.springframework.hateoas.config.HateoasConfiguration required a single bean, but 3 were found:
    - relProviderPluginRegistry: defined by method 'relProviderPluginRegistry' in class path resource [org/springframework/hateoas/config/HateoasConfiguration.class]
    - linkDiscovererRegistry: defined in null
    - entityLinksPluginRegistry: defined by method 'entityLinksPluginRegistry' in class path resource [org/springframework/hateoas/config/WebMvcEntityLinksConfiguration.class]


Action:

Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed

I just add this dependency in my pom file

<dependency>
    <groupId>org.springframework.hateoas</groupId>
    <artifactId>spring-hateoas</artifactId>
    <version>1.1.1.RELEASE</version>
</dependency>

hope that this can help someone

Answer 2

I've removed these dependencies as a workaround and worked:

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger2</artifactId>
    <version>2.4.0</version>
</dependency>

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger-ui</artifactId>
    <version>2.4.0</version>
</dependency>

please let me know if worked for you.

Answer 3

This kind of issue is occurring due to a new feature of Hateoas.

If you want to solve this problem , just embed the following line of codes in your swagger configuration file.

@Primary
@Bean
public LinkDiscoverers discoverers() {
    List<LinkDiscoverer> plugins = new ArrayList<>();
    plugins.add(new CollectionJsonLinkDiscoverer());
    return new LinkDiscoverers(SimplePluginRegistry.create(plugins));
}

I think this is gonna solve your problem as it solved mine.

Answer 4

For Spring boot version 2.1.3.RELEASE users, the following dependencies work fine for hateoas+swagger:

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-hateoas</artifactId>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
        <version>2.9.2</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
        <version>2.9.2</version>
    </dependency>

Answer 5

Best Solution

Add below code in SwaggerConfig class

@Bean
public LinkDiscoverers discovers() {    
    List<LinkDiscoverer> plugins = new ArrayList<>();
    plugins.add(new CollectionJsonLinkDiscoverer());
    return new LinkDiscoverers(SimplePluginRegistry.create(plugins));[enter image description here][1]  
} 

Answer 6

If you want Swagger, but can compromise with HATEOAS, then just remove the HATEOAS dependency and add:

compile group: 'io.springfox', name: 'springfox-swagger-ui', version:'2.9.2'  
compile group: 'io.springfox', name: 'springfox-swagger2', version: '2.9.2'