Resource and ControllerLinkBuilder not found and deprecated

Question

I am using Spring Boot 2.2.0.M1 with HATEOAS and Gradle.

implementation 'org.springframework.boot:spring-boot-starter-hateoas'

Right now, Resource is not found by the IDE (IntelliJ IDEA 2018.3) and ControllerLinkBuilder is marked as deprecated.

package com.example.restfulwebservicegradle.user;

import static org.springframework.hateoas.server.mvc.ControllerLinkBuilder.linkTo;
import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.methodOn;

import com.example.restfulwebservicegradle.User;
import com.example.restfulwebservicegradle.UserDaoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.hateoas.server.mvc.ControllerLinkBuilder;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

import javax.validation.Valid;
import java.net.URI;
import java.util.List;

@RestController
public class UserResource {

    @Autowired
    private UserDaoService service;

    @GetMapping("users/{id}")
    public Resource<User> retrieveUser(@PathVariable int id) {
        User user = service.findOne(id);

        if (user == null)
            throw new UserNotFoundException("id-" + id);


        // Resource not found
        Resource<User> resource = new Resource<User>(user);

        // Deprecated
        ControllerLinkBuilder linkTo = linkTo(methodOn(this.getClass()).retrieveAllUsers());

        resource.add(linkTo.withRel("all-users"));

        return resource;
    }
}

The imports available according to the IDE are:

How can I solve this?

My goal is to found Resource from HATEOAS and to use the substitute of ControllerLinkBuilder.

Roselinerosella

Spring Boot 2.2.0M1 uses Spring HATEOAS 1.0 which has undergone some breaking changes. – Insnare

Answer 1

The most fundamental change is the fact that Spring HATEOAS doesn’t create resources. That’s what Spring MVC/Spring WebFlux does. We create vendor neutral representations of hypermedia. So we renamed those core types:

LINK- https://spring.io/blog/2019/03/05/spring-hateoas-1-0-m1-released#overhaul

1. ResourceSupport is now RepresentationModel
2. Resource is now EntityModel
3. Resources is now CollectionModel
4. PagedResources is now PagedModel

Roa

I'm struggling to find an example on how to feed a controller parameter something that can replace PagedResourcesAssembler<User> pagedResourcesAssembler – Dakar

@Dakar Have you found what you were looking for? Would you please share? – Sputter

@JinKwon Sorry but I haven't worked on that for years and it's out of my scope at the moment. – Dakar

Answer 2

Resource was replaced by EntityModel, and ControllerLinkBuilder was replaced by WebMvcLinkBuilder

Limemann

Precisely what I was looking for – Unbiased

Answer 3

Linking to other replies... following code worked fine for me...

UserResource.java

package com.---.---.restfulwebservices.user;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.hateoas.EntityModel;
import org.springframework.hateoas.Link;
import org.springframework.hateoas.server.mvc.WebMvcLinkBuilder;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

import javax.validation.Valid;
import java.net.URI;
import java.util.List;

import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.methodOn;

@RestController
public class UserResource {
    @Autowired
    private UserDaoService service;

    @GetMapping(path = "/users")
    public List<User> retrieveAllUsers() {
        return service.findAll();
    }

    @GetMapping(path = "/users/{id}")
    public EntityModel<User> retrieveUser(@PathVariable int id) {
        User user = service.findOne(id);
        if (null == user)
            throw new UserNotFoundException("id-" + id);

        EntityModel<User> entityModel = EntityModel.of(user);
        Link link= WebMvcLinkBuilder.linkTo(
                methodOn(this.getClass()).retrieveAllUsers()).withRel("all-users");
        entityModel.add(link);
        return entityModel;
    }

    @PostMapping(path = "/users")
    public ResponseEntity<Object> createUser(@Valid @RequestBody User user) {
        User newUser = service.saveUser(user);
        URI path = ServletUriComponentsBuilder.fromCurrentRequest()
                .path("/{id}").buildAndExpand(newUser.getId()).toUri();
        return ResponseEntity.created(path).build();
    }

    @DeleteMapping(path = "/users/{id}")
    public User deleteUser(@PathVariable int id) {
        User deletedUser = service.deleteUserByID(id);
        if (null == deletedUser)
            throw new UserNotFoundException("id-" + id);
        return deletedUser;
    }
}

pom.xml dependency:

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

Philomenaphiloo

this is exactly what I'm looking for, thanks for sharing – Denison

Answer 4

UserResource controller = methodOn(UserResource.class);
    EntityModel<User> resource = EntityModel.of(user);

    Link link= WebMvcLinkBuilder.linkTo(controller
            .retriveAllUser()).withRel("all-users");

    resource.add(link);
    return resource;

Here UserResource is Controller retriveAllUser is the method which you want to expose

Decongestant

Answer 5

The biggest changes in package structure were driven by the introduction of a hypermedia type registration API to support additional media types in Spring HATEOAS.

https://docs.spring.io/spring-hateoas/docs/current/reference/html/

Jejune

Answer 6

As mentioned by other fellow coders, many changes (deprecations) have happened in HATEOAS, so please use the following code:

@RestController
public class UserResource {

    @Autowired
    private UserDaoService service;

    @GetMapping("users/{id}")
    public Resource<User> retrieveUser(@PathVariable int id) {
        User user = service.findOne(id);

        if (user == null)
            throw new UserNotFoundException("id-" + id);

        //Resource has been replaced by EntityModel
        EntityModel<User> resource = EntityModel.of(user);

        //ControllerLinkBuilder has been replace by WebMvcLinkBuilder
        Link link= WebMvcLinkBuilder.linkTo(methodOn(this.getClass()).retrieveAllUsers()).withRel("all-users");

        resource.add(link);
        return resource;
    }
}

And this is spring-hateoas dependency, you should add this to pom.xml:

<dependency>
    <groupId>org.springframework.hateoas</groupId>
    <artifactId>spring-hateoas</artifactId>
    <version>1.1.0.RELEASE</version>
</dependency>

Calida

Answer 7

Old classes & corresponding new classes can be found from the spring-hateoas migration script to 1.0:

https://github.com/spring-projects/spring-hateoas/blob/main/etc/migrate-to-1.0.sh

ex:

 ControllerLinkBuilder -> hateoas.server.mvc.WebMvcLinkBuilder

Zechariah