Spring guide

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