This document discusses Spring Data REST, which provides a RESTful interface for Spring Data repositories. It covers key Spring Data REST concepts like HATEOAS, projections to customize resource representations, validation, and generating links. The presentation includes demos of basic CRUD operations and search functionality using Spring Data REST. It concludes that Spring Data REST helps build REST APIs quickly but has limitations for complex business logic or when full JSR-303 validation is required.

1. Hypermedia-driven
Web Services
with
Spring Data REST
1

2. Sofiia Vynnytska
2

3. Agenda
• HATEOAS
• Spring Data REST
• Demos
3

4. 44
supershirtguy.com/Funny-T-Shirts/Old%20School%20Homer%20Shirt%20Grey.php

5. Classic way
Controller Service Repository Database
5

6. Simple Junior Engineers API
• Create
• Update
• Delete
• Get by Id
• Get all
6
https://www.uvu.edu

7. DEMO TIME!
7

8. Pros and Cons
+ We know how it works
+ Everything is clear
+ Easy to debug
- A lot of code for simple API
- Code duplication
- No business logic
8
stockfresh.com

9. Client Server
Communication
9

10. says they want something called service.
10
Someone calling themselves a client
www.newslettercartoons.com

11. 11
[{
"id": "1",
"firstName": "Evgeny",
"lastName": "Borisov"
},
{
"id": "2",
"firstName": "Mikalai",
"lastName ": "Alimenkou"
}]
"/juniors"

12. 12
"/juniors" + "/1"
"/engineers/1" + "/skill?newSkill=" + "Java 9"
{
"id": "1",
"firstName": "Evgeny",
"lastName": "Borisov",
"skills": ["Spring", "Spring Boot"]
}

13. 13
memegenerator.net

14. 14
www.business2community.com

15. HATEOAS
15

16. WELL GIRL…
WAIT WHAT DID YOU JUST SAY?16
http://www.express.co.uk/

17. I HATE
OARS 17

18. 18
Hypermedia
As
The
Engine
Of
Application
State

19. 19
{
"id": "1",
"fullName": "Evgeny Borisov",
"skills": ["Spring", "Spring Boot"]
"_links": {
"self": {
"href":"http://localhost:8080/juniors/1"
},
"add-java-9": {
"href":"http://localhost:8080/juniors/1
/skill?newSkill=Java 9"
}
}
}

20. Pros and Cons
+ Discoverability
+ It’s all about server
+ No client knowledge
- Complex
- Learning curve
stockfresh.com 20

21. 21
http://www.thesimpleway.org/

22. Spring Data REST
22

23. It’s REST time 23

24. Spring Data REST
Spring Data
REST API
Implementation
Spring Data
REST
24

25. Support
DATA
25

26. Spring Data REST
@RepositoryRestResource
public interface JuniorEngineerRepository
extends CrudRepository<JuniorEngineer, String> {
}
26

27. Repository detection
27
biwizard.wordpress.com/

28. Repository detection strategy
• Default
• Annotation
28
• Visibility
• All

29. Repository detection strategy
spring.data.rest.detection-strategy=annotated
29

30. Hiding repository and methods
@RepositoryRestResource(exported = false)
public interface JuniorEngineerRepository
extends CrudRepository<JuniorEngineer, String>{
@RestResource(exported = false)
void delete(String id);
}
30

31. Resources
31

32. Resource path
@RepositoryRestResource
public interface JuniorEngineerRepository
extends CrudRepository<JuniorEngineer, String>{
}
32
"/juniorEngineers"
(path = "juniors")

33. Collection resource
33

34. Collection resource
GET
34
"/juniors"
POST
findAll()
save(…)

35. Item resource
35

36. Item resource
36
"/juniors/{id}"
GET
PUT
PATCH
DELETE
findOne(…)
save (…)
save (…)
delete(…)

37. Search resource
37

38. 38
May I have a cigarette
or should I search for it?

39. Search resource
39
@RepositoryRestResource(path = "juniors")
public interface JuniorEngineerRepository
extends CrudRepository<JuniorEngineer, String>{
@RestResource
List<JuniorEngineer> findByProjectIsNull();
}

40. Search resource
40
"/juniors/search"
"/juniors/search/findByProjectIsNull"

41. 41lh5.googleusercontent.com/-rcOOyxZszOw/VIdTCBTMHeI/AAAAAAAACp4/Z9QR4R1C89M/template-minion2.gif

42. Client specific
representations
42

43. 43
www.elitereaders.com

44. Projections
44

45. Projections
@Projection(types = JuniorEngineer.class, name = "minimal")
public interface MinimalProjection {
Set<String> getSkills();
@Value("#{target.firstName} #{target.lastName}")
String getFullName();
}
45

46. Projections discovery
• Same package as domain
• Register manually
RepositoryRestConfiguration
.getProjectionConfiguration()
.addProjection(…)
46

47. Excerpts
47

48. 48

49. Excerpts
@RepositoryRestResource(excerptProjection = DefaultProjection.class)
• Collection
• No item
49

50. DEMO TIME!
50https://movies.alphacoders.com/movies/view/28/The-Matrix

51. Validation
51
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52. Validation
● Bind it by name
@Component("beforeCreateSeniorValidator")
public class SeniorValidator implements Validator {…}
● Register manually
ValidatingRepositoryEventListener
.addValidator("beforeCreate", new SeniorValidator());
52

53. DEMO
53
TIME
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54. Links
54

55. Links
• new Link("localhost:8080/juniors", "juniors");
• ControllerLinkBuilder linkTo(), methodOn()
• RepositoryEntityLinks
55

56. DEMO TIME!
56

57. Summary
57

58. Pros and Cons
+ Helps to start quickly
+ CRUD
+ Projections
+ Hypermedia
- Debugging
- Bugs
- No Bean Validation(JSR-303)
58stockfresh.com

59. When not use Spring Data REST
• Spring, Spring Data in your project
• To much business logic
59

60. Summary
• REST API
• Projections
• Validation
• Links
60

61. Useful links
Spring Data REST Docs
Understanding HATEOAS
Projection representation of single resource
Custom methods validation
61

62. https://github.com/VynnytskaSofiia/demo-
spring-data-rest
62
https://www.facebook.com/sofiia.vynnytska

63. 63cdn2.content.compendiumblog.com

64. 64
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