1. The document discusses various Spring concepts including layers vs domains, Lombok annotations, SOLID principles, testing, exceptions, transactions, and JPA. 2. It provides code examples for implementing concepts like the repository pattern, POJO testing, controller testing, and data access with JPA. 3. Specific topics covered include layering, Lombok, GRASP principles, Spring Boot testing approaches, exception handling best practices, transaction isolation levels, and relationships and optimizations in JPA.

1. Spring Guide

2. 1.

3. Layer VS Domain

4. Layer
Layer

5. Domain

6. domain :
global :
Infra:

7. api : . rest api
api .
domain : .
Embeddable, Enum
.
dto : Request, Response .
exception : Exception
.
Domain

8. global
.
common : Value
. Request,
Response .
config : .
error : .
Exception Guide .
util : .
global

9. infra
.
common : Value
. Request,
Response .
config : .
error : .
Exception Guide .
util : .
infra

11. Repository

12. Aggregate

14. ->

15. , ->

16. 2. Lombok

17. Lombok

18. Lombok
Lombok .
… …

19. @Data @ToString, @EqualsAndHashCode, @Getter, @Setter,
@RequiredArgsConstructor …
…
@Data

20. Setter
.
@Setter

21. Member Coupon ToString .
JPA Json .
ToString

22. ToString .
@ToString(of = {“…”}) .
ToString

23. @EqualsAndHashCode
equals ( )
Set
HashCode
Lombok *.class
@EqualsAndHashCode ..

24. @Builder
@AllArgsConstructor
.
@Builder

25. .
,
.
@Builder

26. ,
, .
Builder

27. .
@Builder.Default Builder .
POJO
@Builder.Default

28. JPA
PROTECTED .
Request HttpMessageConverter
( )

29. lombok.config lombok .
@Data
.
lombok.config

30. ( )
,
, ,
…

31. 3.

33. .

34. ,

35. *

36. .
.
.
.

37. .
.
.
.

38. (state) (behavior) .
.
.
.

39. ' (what)' ' (how)'
.
.
.
.
.

40. Sample Code

41. ' ' .
.
.
. .
' ' . .

42. .
, .
.
.
,
.

43. - What/Who
-
. What/Who .
What/Who
' What' ' Who'
. ' ' .
.

44. -
. Tell, Don't
.
.
.
.

45. .
.
.

46. Sample Code

47. ,
.
.

48. (knowing)
*
*
*

49. .
" "
. .
.
.

50. -
.
.
,
.

51. .
.
, , .
.
. .

52. Sample Code

53. Sample Code

55. 4. SOLID

56. SOLID
SRP:
OCP:
LSP:
ISP:
DIP:

57. * … …
SOLID ?

58. : Open Close Principle
, .
.

60. OCP
PamentController ShinhanCardPaymentService
. (OCP )
(
) .

61. API
. API .
API .

62. Request API
RequestBody API ,
.
shinhanCardNumber, number
Request .

63. Request API
API Request .
DIP ' .' . (
DIP .)
Request .

64. Request API -> OCP
if .
. if
. if .
XXXPaymentService
. PaymentController ,
, .

65. OCP

66. OCP

67. OCP
.
PaymentController CardPayment .
( ) ( )
( ) .
cardPaymentFactory .
,
.

69. : Dependency Inversion Principle
.
.
.

70. .
.
.
.

72. DIP
( ) ( )

73. ( ) ( ) .
JSON , .
.

74. , PaymentRequest Dto CardType
.
.
if . if .

75. XXXPaymentService .
PaymentController , ,
.
. DIP OCP SOLID
.

76. DIP
. .
( ) ( ) . ( ) (
) ( ) .

77. PaymentController PaymentService
cardPaymentFactory ShinhanCardPaymentService .
, PaymenrService
OCP .

79. : Single Responsibility Principle
… ….
.
.
(Actor) ?

80. SRP

81. SRP
:
: Actor
Actor :

82. SRP
Actor
Actor pay
. Actor .
Actor Actor ( )
.
Actor

83. SRP( )

84. SRP( )
.
CardPaymentService payOverseas
.
?
payOverseas pay .

85. .
Actor .
( = Actor)
.

86. ,
?
Actor . Actor
. .
, ,
SRP
.
.

87. SRP( )
.
CardPaymentService payOverseas
.
?
payOverseas pay .

88. SRP( )
PaymentService ,
.
.

89. : The Liskov Substitution Principle
.
Exception .
.
.

90. :

91. : Sample Code

92. :
Coupon calculateDiscountAmount() item getPrice()
Item , Item
SpecialItem
Coupon calculateDiscountAmount item
SpecialItem 0

93. :
instanceof LSP .
Item SpecialItem Item
.
instanceof SpecialItem .
SpecialItem Item
.

94. :
instanceof Item
. SpecialItem
. OCP
LSP Item .
.

95. :

96. :
Item SpecialItem
.
instanceof
.
Item .
OCP . LSP .

97. 5.

98. ?

99. ?
…

100. Spring Boot Test
Bean Context .
.

101. Spring Boot Test
@SpringBootTest .
.
@SpringBootTest .
.
.
.
@RunWith JUnit
.

102. Spring Boot Test

103. Spring Boot Test
properties: {key=value} .
classes: .
@SpringBootConfiguration .
webEnvironment: . Mock
@ActiveProfiles("test")
@Transactional .
WebEnvironment.RANDOM_PORT,
DEFINED_PORT .
@Transactional rollback .

104. @WebMvcTest

105. @DataJpaTest
@DataJpaTest JPA .
, JPA , ,
.
.
@Entity JPA .

106. @DataJpaTest

107. @DataJpaTest
@AutoConfigureTestDatabase Replace.Any
.
@AutoConfigureTestDatabase(replace =
AutoConfigureTestDatabase.Replace.NONE) @ActiveProfiles("test")
.
@DataJpaTest .
.

108. @RestClientTest
@RestClientTest REST .
REST JSON .

109. @RestClientTest
@RestClientTest Bean .
@Rule @Before, @After
.
.
MockRestServiceServer REST .
RestTemplate .
.
rest_test() .
test.json ( .).

110. 1. Mock Service = POJO
2. WebMvc Test
3. Spring Boot Test

111. Code

112. Code

113. Repository Test
Code

114. POJO
Code

116. POJO
Test , Spring Boot
. Slice
.
POJO POJO
.
POJO
POJO .
.
.

117. POJO
Document

118. Matchers AssertJ .
assertThat(coupon.isUsed()) .
.

119. Controller
json
.
json .

120. Controller

122. Import Set up
SQL given
when, then
.
.
.
. member insert
.
data.sql
.

123. Import Set up ->

124. Junit5 With Kotlin & Spring Boot 2.2

128. Junit5 With Kotlin & Spring Boot 2.2

129. Junit5 With Kotlin & Spring Boot 2.2

130. Junit5 With Kotlin & Spring Boot 2.2

131. Junit5 With Kotlin & Spring Boot 2.2
* AssertJ BDD
BDDAssertion
.

134. 6. Exception

135. Exception ?

136. .
.

137. .
.

138. Exception

139. .
.
.
.

140. .
.
UnCheckedException
.
:

141. . ( )
. ( )
Catch . ( )
Catch . ( )

142. Try Catch

143. Check Exception VS UnChecked Exception
Error .
Error …
Checked, Unchecked Exception
Checked = . (
, ) ->
Unchecked =
Runtime Exception

144. Check Exception VS UnChecked Exception
Error .
Error …
Checked, Unchecked Exception
Checked = . ( , ) ->
Unchecked =

145. Check Exception
JsonProcessingException IOException
Exception Checked Exception .
throws try catch
throw .
.
Unchecked Exception
.

146. Rollback

147. Rollback
(1) RuntimeException
yun member
rollback .
(2) IOException
wan rollback
commit .
member yun, wan
insert yun
rollback wan rollback
commit .

148. Checked Exception Rollback ?

149. Checked Exception Rollback ?
Checked Exception
.
.
.
Rollback
( 100%)

150. Checked Exception Rollback ?
.

151. …

152. (1)…
Checked Exception
.
SQLException
? + insert
RuntimeException
.

153. (1)…
Exception
Exception .
DuplicateEmailException (Unchecked Exception)
.
Checked Exception Unchecked Exception
. JPA
Checked Exception
RuntimeException .

154. Checked Exception
. throw
try catch .
.

155. Unckecked Exception
Checked Exception Unckecekd Exception
.
.

156. API Server Exception

157. Error Response
Error Response Error Response .
.
Map<Key, Value> .
.

158. Error Response
message : message .
status : http status code . header
.
errors : field, value, reason
. @Valid JSR 303: Bean
Validation .
errors null
[] . null
. null .
code :

159. Error Response
ErrorResponse . POJO
errorResponse.getXXX();
.
Exception ErrorResponse
. .

160. @ControllerAdvice
@ExceptionHandler
Error Response .
BusinessException
. .

161. Error Code
enum .
,
.
C001 enum
. Common
.

162. Business Exception
Business Exception Exception .
. Exception
.
Exception Business Exception .
Exception .
.
.
, ,
. Exception .

163. BusinessException
BusinessException InvalidValueException, EntityNotFoundExceptuon .
InvalidValueException : Excetion
,
EntityNotFoundException :
findById, findByCode

164. BusinessException
BusinessException .
BusinessException
.
handleBusinessException .
. BusinessException
.

165. .
.
.
. Bean Validation
. @ControllerAdvice .
.

166. Custom Validation (1)
Bean Validation
.
.

167. Custom Validation (1)

168. Custom Validation (1)

169. Custom Validation (2)
JSR 303 Validation . @NotNull,
@NotEmpty, @Email Validation .
, .
JSON account, card paymentMethod @NotNull,
@NotEmpty . ConstraintValidator .

170. ConstraintValidator
ConstraintValidator Validation ConstraintValidator
.
. Validation , ( ) .

171. ConstraintValidator
.
Interceptor .
ConstraintValidator (Interceptor ) .

172. ErrorResponse
- Error Response
ErrorReponse .
ConstraintValidator @Valid
MethodArgumentNotValidException
@ControllerAdvice
ErrorResponse
.

173. ErrorResponse

174. ConstraintValidator

175. ConstraintValidator

176. 7.

178. bRepository.save(B("B"))
aRepository.save(A("A")) Rollback .

179. CGLIB Proxy . (
Dynamic Proxy )
Proxy .
AOP

180. JPA Repository interface ?

181. @Transactional aRepository, bRepository .
Service
.

182. bRepository.save(B("B")) exception
bRepository.save(B("B")), aRepository.save(A("A")) rollback
.

183. Isolation Level
5

186. SQL 10 sleep
increase() RuntimeException
READ_UNCOMMITTED, READ_COMMITTED

188. 1 . (
)
2 (
READ_UNCOMMITTED 2
1
)
1 wake up Exception
2 15
Duty Read .

189. READ_COMMITTED
.
2 1
.
.
READ_COMMITED DB
.
/
.

190. 1. 1 sleep ( )
2. 2 . ( READ_COMMITTED
.)
3. 1 .
Nonrepeatable Read
REPEATABLE_READ
1 , 2

191.
.
REPEATABLE_READ .
REPEATABLE_READ
1. 1 sleep ( )
2. 2 1 .
REPEATABLE_READ DB
. /
.

192. 1. 1
2. 2 insert
3. 1
( )
.
SERIALIZABLE .
SERIALIZABLE .
SERIALIZABLE

194. : Lost Update

195. : Lost Update
T1, T2 .
T1 , T2 T1 T1
T2 .
T1 T2 T1 .

197. .
.
.
DBMS .
.
.

198. .
. ->
. ->

199. 1
2 ,
2 1
.
1
. 2
. 1
2 2
1 .
.

200. 1.
2.
3.
.
4.
.
.
5.
.

201. DBMS
. DBMS for
update
.
JPA EntityManager LockModeType
find() ,
LockModeType.PESSIMISTIC_WRITE
.
JPA DBMS
, PESSIMISTIC_WRITE
for update
.

202. 1. 1: A
2. 2: B
3. 1: B
4. 2 : A
. 1
2 .
,
. .
. JPA
.
JPA javax.persistence.lock.timeout .
. (DBMS . )

203. Isolcation Level REPEATABLE_READ DB
.
1
2
.
JPA REPEATABLE_READ
.
In JPA

204. JPA . 1
A , B . Commit
.
REPEATABLE_READ ( )
1 REPEATABLE_READ .
In JPA

205. A B
. second
lost updates problem .
. . 3 .
1. : A B .
2. : A B .
3. : A B .

206. 1. .
2. .
.
3.
.
4. 1
.

207. .
.
,
.
,
.
DBMS
.

208. .
1
, .
.
1 . ,
.

209. 1. 1
2. 2
3. 1 ( 2
), 6 .
4. 2 ,
6 2

210. JPA .
@Version
.
JPA UPDATE
@Version
. 10 UP-
DATE
.

211. . Repository
.
JPA
.

212. Flow

213. Application Event

214. Application Event
( )
( , )

215. Application Event
OrderService
. , OrderService .
Application Event .

216. Application Event
- Application Event Subscriber
.
OrderService
.

217. Application Event
(Item) , event .
.
.
.

218. JPA

219. JPA Setter

220. , ,
setter .
setter
.
Setter .

221. Account updateMyAccount
.
.
MyAccountReq .
DTO
.
Setter .

222. setter
.
.
setter
setter
.

223. JPA

224. .
.
1:1 OneToOne .
.
?
OneToOne

225. .
JPA
( , , )
.
?

226. order coupon_id
SQL .
coupon
coupon order order INSERT
SQL , coupon order_id
2 .
Order : INSERT SQL

227. OneToOne
.
order coupon_id
coupon
order_id .
OneToMany
.
.
Order :

228. OneToOne ,
. OneToMany
Many . OneToMany
OneToMany .
OneToOne .
<->
OneToOne . ( .
)
.

229. @JoinColumn nullable false . NOT
NULL .
JPA DDL Spec .

230. NOT NULL . JPA SQL
.
NOT NULL .
. .

231. .
applyCoupon .

232. order
.
order 1,000
.
null .
.

233. .
1:N .
1
OneToMany

234. Delivery DeliveryLog
PENDDING
.
Delivery

235. CaseCade PERSIST Delivery
DeliveryLog .
CaseCade PERSIST
,
insert query .
Delivery

236. JPA
.
.
Delivery DeliveryLog
.
(orphanRemoval) : DeliveryLog

237. delivery, deliverylog
Delivery .
delete SQL delivery_log
delivery .
orphanRemoval
.
(orphanRemoval) : Delivery

238. DeliveryLog clear() DeliveryLog
Delivery DeliveryLog .
(orphanRemoval) :

239. Embedded

240. String Email . .
. .
Email String Email
.

241. String Account ,
.
Account . Account
.
.
.
Email Email . Email
. . .
(Rich Object)

242. Money , , .
.

243. JPA N+1

244. ERD

245. N+1

246. N+1

247. N+1

248. Member N+1 .
N+1

249. N+1
JPQL . findById()
JPQL SQL . .
1. JPQL .
2. .
3. ( ) .

250. N+1
JPQL JPA SQL . JPQL ,
JPQL SQL .

251. : Batch Size
@BatchSize(size = 5) size . size where in
size where in .
spring.jpa.properties.hibernate.default_batch_fetch_size=1000 properties

252. : Fetch
fetch . Fetch
.
Fetch
.

253. Fetch
SQL . JPQL
select .
Lazy N+1
.

254. Fetch
Fetch API .
limit offset .
API
.
FULL Scan
limit .
Full Sacn
.
API
.

255. Fetch
.
. annot simultaneously fetch
multiple bag . List -> Set .

256. Fetch
.
. annot simultaneously fetch
multiple bag . List -> Set .

258. Properties

260. key
properties value .
amount 100 int amount
. .
email email-address getProperty()
email-address .
1 runtime
NullPointException .

261. : ConfigurationProperties

263. : ConfigurationProperties
Immutable Properties

264. @ConstructorBinding data class
.
2.2.1
@ConfigurationProperties scanning
disabled
@EnableConfigurationProperties
.

265. END