Lightweight J2EE development with Spring (special for UADEV)

Lightweight Enterprise
Java Development using
Spring Framework
Oleksiy Rezchykov
Eugene Scripnik

About us
 Software Engineers

 Working with Spring since 2006

 Pragmatic programmers

 SpringByExample.com.ua
founders

SpringByExample.com.ua
2
@ua_spring #uadevclub

Contents
 Spring origins

 IoC using Spring

 Persistence with Spring

 Declarative caching using @Cachable

 Web applications with Spring MVC

 Spring ecosystem

 Framework criticism
3

J2EE 5
Development

4

SpringFramework
history
 In October 2002 Rod Johnson wrote
his famous book

 The first milestone release 1.0 -
June 2004

 Company renamed from Interface21
to SpringSource in 2007

 SpringSource acquired by VMWare
in 2009

 Rod Johnson left VMWare – July
2012
5

Inversion of Control
 Inversion of regular approach where object was
responsible for satisfying it’s own dependencies

 Implementation of Dependency Injection

 Container instantiates and wires dependencies

6

Injection types
 Setter injection– when you are using setter to fulfill
bean dependency

 Constructor injection – when constructor is called to
set-up a bean with dependencies

 Method injection

7

Context
 An object which contains beans declarations with
their dependencies

 BeanFactory interface implementation

8

XML namespaces

9

Context

10

Context usage

11

Bean lifecycle
 Depends on scope and lazy initialization

 Main bean scopes:

Singleton and Prototype

(Also there are multiple web scopes)

12

Bean instantiation order

13

Bean Post-processing
• Bean instantiated for singletons with
Bean
instantiation
eager initialization

Dependency
• Dependencies are injected into beans
injection

• Bean post-processing actions
Bean post-
processing
• You can put your custom logic in here

14

Map, List, Set, Prop, Nul
l

15

Map, List, Set, Prop, Nul
l

16

Util namespace

17

Component model

18

@Autowired
 Spring proprietary annotation for property injection

 Supports @Qualifier to select implementation by
name if more than one exists in context

 Has required parameter to enforce dependency
loading

19

@Autowired

20

@Inject
 Context and Dependency Injection (CDI) standard
JSR-299

21

@Resource
 JSR 250 (Common annotations)

 Supports @PostConstruct and @PreDestroy as
well

22

Resource loading and
i18n

23

Resource loading and
i18n

24

SpEl
 Stands for Spring Expression Language

 Can be used in the xml context

 Can be used in bean classes

25

SpEl

26

Java Spring Config
 @Configuration

 @Bean

 Support for Environment and Profiles

27

Java Spring Config

28

Environment abstraction
& context profiles
 Environment abstraction introduced in Spring 3.1

 Can be declaratively and programmatically
configured

 Affects property resolution

 Affects bean profiles

29

Environment abstraction
& context profiles

30

AOP
A programming paradigm which allows to separate
cross-cutting concerns

Cross-cutting logic:

 Logging

 Tracing

 Security

31

AOP
 Aspect

 Advice

 Join point

 Pointcut

32

AOP

33

Spring AOP
 Spring AOP defaults to using standard J2SE
dynamic proxies for AOP proxies. This enables any
interface (or set of interfaces) to be proxied.

 Spring AOP can also use CGLIB proxies. This is
necessary to proxy classes, rather than interfaces

 It is good practice to program to interfaces rather
than classes, business classes normally will
implement one or more business interfaces.

34

AspectJ
 Spring AOP is often uses the AspectJ declaration
style
 AspectJ itself uses Load Time Weaving (LTW) to
modify the bean code according to Aspect logic
 LTW could do much more than dynamic proxies but it
is more time-consuming operation. This means that
LTW has a performance drawback.

35

“pure” AspectJ

36

“pure” AspectJ

37

Persistence with Spring
 Building DAO

 Spring Data

 Embedded Datasources

 JDBC vs ORM DAO’s

 Integration testing with Spring

 @Transactional & transactions with Spring

38

Spring supports
 JDBC

 JPA

 JDO

 Concrete ORM

39

Spring Data
 RDBMS: JPA, JDBC Extensions

 BigData: ApacheHadoop

 DataGrid: GermFire

 HTTP: REST

 Key-value stores: Redis

 Document Stores: MongoDB

 Graph Databases: Neo4j

 Column stores: Hbase

40

Persistence layer
• Persistence service which has domain specific logic
Service

• Spring JDBCTemplate
• SessionFactory, EntityManagerFactory
Repository
(DAO) • Redis/Mongo template

• RDBMS (or NoSQL)
DB

41

JDBCTemplate
 Useful interface

 No boilerplate code

 Exception handling

42

JDBCTemplate

43

JDBC namespace

44

Spring Data JPA
 CRUD

45

Spring Data JPA
 Query DSL

46

Transactions in Spring
 Support for ACID transactions

 Declarative and programmatic

47

Transaction managers
 Spring support both container managed and
framework managed transactions

Managers:

 DataSourceTransactionManager

 HibernateTransactionManager

 JPATransactionManager

 JTATransactionManager

48

@Transactional
 Transaction propagation

 Read-only transactions

 Built using Spring AOP

49

Persistence layer testing
 Context loading in test

 Environment abstraction and profiles usage

 Transactional methods

 Embedded data source could be used

50

Persistence layer testing

51

@Cacheable
 One-two-three magic (not always work as expected)

 Support for JCache (JSR-107)

52

@Cacheable
 <cache:annotation-driven> or @EnableCaching

 CacheManager instance in the context

 @Cacheable, @CachePut, @CacheEvict

53

Spring MVC
 Application context

 Dispatcher Servlet and it’s context

 Controllers and mappings

 Implementing CRUD logic

 REST

 Testing MVC

54

Application & Dispatcher
servlet context

55

Front controller and
MVC

56

URL mappings
 @RequestMapping

57

View resolvers
 AbstractCachingViewResolver

 XmlViewResolver

 ResourceBundleViewResolver

 UrlBasedViewResolver

 InternalResourceViewResolver

 VelocityViewResolver / FreeMarkerViewResolver

 ContentNegotiatingViewResolver
58

View resolvers

59

CRUD in one place

60

REST in Spring MVC
 Starting Spring 3.1.x

 ContentNegotiatingViewResolver

 @ResponseBody combined with produces

 @RequestBody combined with consumes

61

REST in Spring MVC

62

Testing MVC
 Starting from Spring 3.2

 spring-test-mvc project

 Server-side Spring MVC tests

 New Spring Mocks

 Different strategies

63

Testing MVC

64

Testing MVC

65

Just to mention
 Type conversion

 Formatter SPI

66

Just to mention
 Type conversion

 Formatter SPI

67

Just to mention
 Flash attributes and Redirect attributes

68

Spring in 2012

69

Just to mention
 Spring Roo

 Spring Hadoop

 Spring Android

70

Criticism
 Every tool should be used only if you could not
solve your task without it – KISS

 When a lot of stuff come out-of-the-box it is not
always good - YAGNI

 When something is broken it is pain in the …

 Open source but VMWare

71

Sources
 http://static.springsource.org/spring/docs/3.1.x/sprin
g-framework-reference/html/index.html

 https://github.com/springbyexample/spring-by-
example

 https://github.com/mcgray/spring-vaadin

 http://rstoyanchev.github.com/spring-32-test-
webapps/

72

Questions?
@ua_spring

oleksiy.rezchykov@gmail.com
eugene.scripnik@gmail.com


73

Lightweight J2EE development with Spring (special for UADEV)

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