Spring By Example One Day Workshop

Spring By Example
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

Contents
 Intro

 IoC using Spring

 Persistence with Spring

 Web applications with Spring MVC

3
@ua_spring

Intro
 What we will do today?

 Meet some new faces

 Learn some new stuff

 Code some new stuff

4
@ua_spring

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

5
@ua_spring

Spring in 2012

6
@ua_spring

IoC using Spring
 Buiding xml contexts

 Bean scopes & lifecycles

 Constructor vs Setter injection

 Property placeholders

 p & c and util name spaces

 Annotation context

 Using component scan

 AOP usage

 Spring AOP vs AspectJ

7
@ua_spring

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

8
@ua_spring

IoC
 Pros vs Cons (to discuss)

9
@ua_spring

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

10
@ua_spring

CI vs SI
 Pro vs Cons (to discuss)

11
@ua_spring

Context
 An object which contains beans declarations with
their dependencies

 BeanFactory interface implementation

12
@ua_spring

XML namespaces

13
@ua_spring

Context

14
@ua_spring

Context usage

15
@ua_spring

Bean lifecycle
 Depends on scope and lazy initialization

 Main bean scopes:

Singleton and Prototype

(Also there are multiple web scopes)

16
@ua_spring

Bean instantiation order

17
@ua_spring

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

18
@ua_spring

Property Editors

19
@ua_spring

Multiple config files

20
@ua_spring

Bean definition
inheritance

21
@ua_spring

Inner Beans

22
@ua_spring

Factory Method

23
@ua_spring

Map, List, Set, Prop,
Null

24
@ua_spring

Map, List, Set, Prop, Nul
l

25
@ua_spring

Util namespace

26
@ua_spring

Component model

27
@ua_spring

@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

28
@ua_spring

@Autowired

29
@ua_spring

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

30
@ua_spring

@Resource
 JSR 250 (Common annotations)

 Supports @PostConstruct and @PreDestroy as
well

31
@ua_spring

Autowiring
An appropriate bean for dependency is found through:

 Type

 Name

 Type and Name combination

32
@ua_spring

Resource loading and
i18n

33
@ua_spring

Resource loading and
i18n

34
@ua_spring

SpEl
 Stands for Spring Expression Language

 Can be used in the xml context

 Can be used in bean classes

35
@ua_spring

SpEl

36
@ua_spring

Java Spring Config
 @Configuration

 @Bean

 Support for Environment and Profiles

37
@ua_spring

Java Spring Config

38
@ua_spring

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

 Can be declaratively and programmatically
configured

 Affects property resolution

 Affects bean profiles

39
@ua_spring

& context profiles

40
@ua_spring

& context profiles

41
@ua_spring

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

Cross-cutting logic:

 Logging

 Tracing

 Security

42
@ua_spring

AOP
 Aspect

 Advice

 Join point

 Pointcut

43
@ua_spring

AOP

44
@ua_spring

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.

45
@ua_spring

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.

46
@ua_spring

Persistence with Spring
 Building DAO

 Embedded Datasources

 JDBC vs ORM DAO’s

 Integration testing with Spring

 @Transactional & transactions with Spring

47
@ua_spring

Spring supports
 JDBC

 JPA

 JDO

 Concrete ORM

 NoSQL templates (Mongo/Redis)

 Graph DB abstractions - Spring Data Graph project

48
@ua_spring

Persistence layer
• Persistence service which has domain specific logic
Service

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

• RDBMS (or NoSQL)
DB

49
@ua_spring

JDBCTemplate
 Useful interface

 No boilerplate code

 Exception handling

50
@ua_spring

JDBCTemplate

51
@ua_spring

JDBC namespace

52
@ua_spring

Intro to Hibernate
Object Relational Mapping - is a programming
technique for converting data between incompatible
type systems in object-oriented programming
languages. This creates, in effect, a "virtual object
database" that can be used from within the
programming language.

53
@ua_spring

ORM main challenges
 Object inheritance

 Object relations

54
@ua_spring

Hibernate main parts
 SessionFactory

 Session

 Entity

55
@ua_spring

Transactions in Spring
 Support for ACID transactions

 Declarative and programmatic

56
@ua_spring

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

Managers:

 DataSourceTransactionManager

 HibernateTransactionManager

 JPATransactionManager

 JTATransactionManager

57
@ua_spring

@Transactional
 Isolation levels

 Transaction propagation

 Read-only transactions

58
@ua_spring

Read-only transactions
 A read-only transaction can be used when your
code reads but does not modify data. Read-only
transactions can be a useful optimization in some
cases, such as when you are using Hibernate.

59
@ua_spring

Isolation levels
 DEFAULT - The default isolation level for the
underlying resource (usually this is the
READ_COMMITTED isolation level)

60
@ua_spring

Isolation levels
 READ_UNCOMMITTED - Least restrictive isolation
level. A transaction can read data updates even if
they haven't yet been committed. (The updates
might subsequently be rolled-back).

61
@ua_spring

Isolation levels
 READ_COMMITTED - A transaction can only read
data that has already been committed. The
transaction doesn't see uncommitted updates.

62
@ua_spring

Isolation levels
 REPEATABLE_READ - A transaction always reads
the same value after it has read some data. Other
transactions can update the data in parallel with the
original transaction.

63
@ua_spring

Isolation levels
 SERIALIZABLE - This is the most restrictive
isolation level. Transactions are completely isolated
from each other. Resource managers frequently
implement this isolation level by locking large
amounts of data

64
@ua_spring

Propagation
 NOT_SUPPORTED

Suspends client's transaction until bean method is complete

65
@ua_spring

Propagation
 SUPPORTS

If client has transaction, bean method is included in it

If client doesn't have transaction, bean method doesn't
create one

66
@ua_spring

Propagation
 REQUIRED

If client has a transaction, bean method is included in it

If client doesn't have a transaction, bean method creates
one

67
@ua_spring

Propagation
 REQUIRES_NEW

If client has a transaction, bean method creates new one
anyway

If client doesn't have a transaction, bean method creates
one

68
@ua_spring

Propagation
 MANDATORY

If client has a transaction, bean method uses it

If client doesn't have a transaction, exception!

69
@ua_spring

Propagation
 NEVER

If client has a transaction, exception!

If client doesn't have transaction, bean method doesn't
create one

70
@ua_spring

Persistence layer testing
 Context loading in test

 Environment abstraction and profiles usage

 Transactional methods

 Embedded data source could be used

71
@ua_spring

Persistence layer testing

72
@ua_spring

Spring MVC
 Application context

 Dispatcher Servlet and it’s context

 Controllers and mappings

 Implementing CRUD logic

 Using Spring for UI tests

73
@ua_spring

Application & Dispatcher
servlet context

74
@ua_spring

Front controller and
MVC

75
@ua_spring

URL mappings
 @RequestMapping

76
@ua_spring

View resolvers
 AbstractCachingViewResolver

 XmlViewResolver

 ResourceBundleViewResolver

 UrlBasedViewResolver

 InternalResourceViewResolver

 VelocityViewResolver / FreeMarkerViewResolver

 ContentNegotiatingViewResolver
77
@ua_spring

View resolvers

78
@ua_spring

CRUD in one place

79
@ua_spring

Using Spring for UI tests
 Integration testing of Controllers

 Spring as a framework for Selenium UI tests

80
@ua_spring

Spring By Example One Day Workshop

More Related Content

Viewers also liked

Similar to Spring By Example One Day Workshop

Recently uploaded

Spring By Example One Day Workshop

Editor's Notes