HATEOAS methods not found - spring-boot

Question

My controller can't seem to find the HATEOAS methods like "linkTo".
Am I missing something?
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.springframework</groupId>
<artifactId>provider</artifactId>
<version>0.1.0</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.1.5.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- Spring Security -->
<!-- Auto configured, remove dependencies to disable. -->
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-config</artifactId>
</dependency>
<!-- OAuth 2.0 -->
<dependency>
<groupId>org.springframework.security.oauth</groupId>
<artifactId>spring-security-oauth2</artifactId>
<version>2.0.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test-mvc</artifactId>
<version>1.0.0.M2</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
</dependency>
<!-- Spring MongoDB -->
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-mongodb</artifactId>
</dependency>
<!-- Spring REST MVC -->
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-rest-webmvc</artifactId>
</dependency>
<!-- Dozer: DTO/Entity Mapper -->
<dependency>
<groupId>net.sf.dozer</groupId>
<artifactId>dozer</artifactId>
<version>5.3.2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
<dependency>
<groupId>joda-time</groupId>
<artifactId>joda-time</artifactId>
</dependency>
</dependencies>
<properties>
<start-class>com.provider.core.Application</start-class>
</properties>
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-snapshots</id>
<url>http://repo.spring.io/libs-snapshot</url>
<snapshots><enabled>true</enabled></snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<url>http://repo.spring.io/libs-snapshot</url>
<snapshots><enabled>true</enabled></snapshots>
</pluginRepository>
</pluginRepositories>
</project>
Controller
package com.provider.core;
import org.dozer.DozerBeanMapper;
import org.dozer.Mapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import com.provider.account.Account;
import com.provider.account.AccountDTO;
#Controller
public class AccountController
{
private static final Logger logger = LoggerFactory.getLogger(AccountController.class);
#Autowired private AccountRepository repo;
#RequestMapping(value = "account", method = RequestMethod.POST)
public #ResponseBody HttpEntity<AccountDTO> createAccount(#RequestBody AccountDTO accountDto) {
logger.info("Start createAccount()");
Mapper mapper = new DozerBeanMapper();
Account account = mapper.map(accountDto, Account.class);
Account savedAccount = repo.save(account);
AccountDTO savedAccountDto = mapper.map(savedAccount, AccountDTO.class);
// DOES NOT COMPILE "linkto" not defined.
savedAccountDto.add(linkTo(AccountController.class).slash(savedAccountDto.getId()).withSelfRel());
return new ResponseEntity<AccountDTO>(savedAccountDto, HttpStatus.OK);
}
}

Answer 1

In case you are using HATEOAS v1.0 and above (Spring boot >= 2.2.0), do note that the classnames have changed. Notably the below classes have been renamed:
ResourceSupport changed to RepresentationModel
Resource changed to EntityModel
Resources changed to CollectionModel
PagedResources changed to PagedModel
ResourceAssembler changed to RepresentationModelAssembler
More information available in the official documentation here.
When using Spring boot starter, the below dependency would suffice to include HATEOAS:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-hateoas</artifactId>
</dependency>
Hoping this information will help someone like me who searched for hours to find why Resource class was not getting resolved.

Answer 2

Looks like your POM is missing the spring-hateoas dependency.
So first add this to pom.xml:
<dependency>
<groupId>org.springframework.hateoas</groupId>
<artifactId>spring-hateoas</artifactId>
<version>0.15.0.RELEASE</version>
</dependency>
Then you can add this static import and your code should compile:
import static org.springframework.hateoas.mvc.ControllerLinkBuilder.*

Answer 3

If you are using HATEOAS in eclipse(Version : Oxygen.3a Release (4.7.3a)), please note that the class names have changed.
Resource changed to EntityModel
Resources changed to CollectionModel
More information available in the official documentation below link ->
https://docs.spring.io/spring-hateoas/docs/current/reference/html/
When using Spring boot starter, you've to use below dependency to include HATEOAS:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-hateoas</artifactId>
</dependency>
Demo Code :
EntityModel<Users> resource = new EntityModel<Users>(user);
ControllerLinkBuilder linkTo = linkTo(methodOn(this.getClass()).retrieveAllUsers());
resource.add(linkTo.withRel("all-users"));
Note : You have to import
import static org.springframework.hateoas.server.mvc.ControllerLinkBuilder.*;
Hope this information is helpful to find why Resource class was not getting resolved !!

Answer 4

Add following dependency :-
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-hateoas</artifactId>
<version>2.4.0</version>
</dependency>
Follow Sample Code :-
import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.*;
#GetMapping(path = "/users/{id}")
public EntityModel<User> getUserInfo(#PathVariable int id) {
User user = userDao.getUser(id);
EntityModel<User> entityModel = EntityModel.of(user);
Link link = WebMvcLinkBuilder.linkTo(methodOn(this.getClass()).getUserList()).withRel("user-list");
entityModel.add(link);
if(user == null) {
throw new UserNotFoundException("User not found with id : "+id);
}
return entityModel;
}

Answer 5

Add below dependency in pom.xml,it could resolve your issue.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-hateoas</artifactId>
</dependency>
If above doesn't work then easy solution is got with older versions of hateos.
As new versions of Hateoas has been changed totally, below link can help you.
https://docs.spring.io/spring-hateoas/docs/current/reference/html/
Am mentioning some major changes in methods of Hateoas
ResourceSupport is now RepresentationModel
Resource is now EntityModel
Resources is now CollectionModel
PagedResources is now PagedModel
The LinkDiscoverer API has been moved to the client package.
The LinkBuilder and EntityLinks APIs have been moved to the server package.
ControllerLinkBuilder has been moved into server.mvc and deprecated to be replaced by WebMvcLinkBuilder.
RelProvider has been renamed to LinkRelationProvider and returns LinkRelation instances instead of Strings.
VndError has been moved to the mediatype.vnderror package

Answer 6

There are some nomenclature changes in the recent release(2.2.0 or >). Refer to this document

Answer 7

I'm gonna leave this here in case someone new needed it:
ControllerLinkBuilder is deprecated and you should use WebMvcLinkBuilder instead (check this https://docs.spring.io/spring-hateoas/docs/1.0.0.M1/apidocs/org/springframework/hateoas/server/mvc/ControllerLinkBuilder.html)
so instead if:
import static org.springframework.hateoas.server.mvc.ControllerLinkBuilder.*;
use this:
import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.*;

Answer 8

This issue occurred in my case because there are two hateoas jars one has the resource interface and other has the implementaion with same groupId and arifactId.
To Resolve this issue -->
Downgrade your STS if you're using 4.* to 3.*
Add the below dependency if you're using spring boot
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-hateoas</artifactId>
</dependency>
After adding this dependency run below commands in the command prompt where you're pom.xml is present
mvn clean install package
mvn eclipse:eclipse
This steps resolved issue for me.

Answer 9

Might be helpful for some, I see one thing thats not addressed here and couple of comments ask for this:
Cannot resolve symbol 'hal'
Cannot resolve symbol 'Jackson2HalModule'
hal module is under media now. So
org.springframework.hateoas.hal.Jackson2HalModule
is now replaced with
org.springframework.hateoas.mediatype.hal.Jackson2HalModule

Answer 10

The below imports are required
import org.springframework.hateoas.EntityModel;
import org.springframework.hateoas.Link;
import org.springframework.hateoas.server.mvc.WebMvcLinkBuilder;
With a static import from WebMvcLinkBuilder for all methods

Answer 11

Like others have said, hateoas had a lot of changes. I still was running into the same issues though even with the names properly changed to EntityModel etc. because it wasn't letting me import anything from org.springframework.hateoas.
I was using maven with IntelliJ IDEA and had to right-click my pom.xml, -> maven, -> reload project. Then it let me import things from hateoas properly.
Hope this helps someone!