Lightweight J2EE development with Spring (special for UADEV)

Lightweight Enterprise Java Development

using Spring Framework

Oleksiy RezchykovEugene Scripnik

SpringByExample.com.ua @ua_spring #uadevclub

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About us Software Engineers

Working with Spring since 2006

Pragmatic programmers

SpringByExample.com.ua founders


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Contents Spring origins

IoC using Spring

Persistence with Spring

Declarative caching using @Cachable

Web applications with Spring MVC

Spring ecosystem

Framework criticism

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J2EE 5 Development



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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


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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


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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


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Context An object which contains beans declarations

with their dependencies

BeanFactory interface implementation


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XML namespaces


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Context


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Context usage


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Bean lifecycle Depends on scope and lazy initialization

Main bean scopes:

Singleton and Prototype

(Also there are multiple web scopes)


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Bean instantiation order


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Bean Post-processingBea

n instantiation

• Bean instantiated for singletons with eager initialization

Dependency

injection

• Dependencies are injected into beans

Bean

post-

processing

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

in here


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Map, List, Set, Prop, Null


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Map, List, Set, Prop, Null


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Util namespace


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Component model


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@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


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@Autowired


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@Inject Context and Dependency Injection (CDI)

standard JSR-299


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@Resource JSR 250 (Common annotations)

Supports @PostConstruct and @PreDestroy as well


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Resource loading and i18n


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Resource loading and i18n


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SpEl Stands for Spring Expression Language

Can be used in the xml context

Can be used in bean classes


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SpEl


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Java Spring Config @Configuration

@Bean

Support for Environment and Profiles


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Java Spring Config


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Environment abstraction & context

profiles Environment abstraction introduced in Spring 3.1

Can be declaratively and programmatically configured

Affects property resolution

Affects bean profiles


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Environment abstraction & context

profiles


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AOPA programming paradigm which allows to separate cross-cutting concerns

Cross-cutting logic:

Logging

Tracing

Security


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AOP Aspect

Advice

Join point

Pointcut


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AOP


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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.


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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.


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“pure” AspectJ


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“pure” AspectJ


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Persistence with Spring

Building DAO

Spring Data

Embedded Datasources

JDBC vs ORM DAO’s

Integration testing with Spring

@Transactional & transactions with Spring


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Spring supports JDBC

JPA

JDO

Concrete ORM


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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


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Persistence layer

Service

• Persistence service which has domain specific logic

Repository (DAO)

• Spring JDBCTemplate• SessionFactory, EntityManagerFactory• Redis/Mongo template

DB

• RDBMS (or NoSQL)


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JDBCTemplate Useful interface

No boilerplate code

Exception handling


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JDBCTemplate


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JDBC namespace


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Spring Data JPA CRUD


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Spring Data JPA Query DSL


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Transactions in Spring

Support for ACID transactions

Declarative and programmatic


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Transaction managers

Spring support both container managed and framework managed transactions

Managers:

DataSourceTransactionManager

HibernateTransactionManager

JPATransactionManager

JTATransactionManager


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@Transactional Transaction propagation

Read-only transactions

Built using Spring AOP


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Persistence layer testing

Context loading in test

Environment abstraction and profiles usage

Transactional methods

Embedded data source could be used


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Persistence layer testing


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

expected)

Support for JCache (JSR-107)


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@Cacheable <cache:annotation-driven> or

@EnableCaching

CacheManager instance in the context

@Cacheable, @CachePut, @CacheEvict


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Spring MVC Application context

Dispatcher Servlet and it’s context

Controllers and mappings

Implementing CRUD logic

REST

Testing MVC


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Application & Dispatcher servlet

context


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Front controller and MVC


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URL mappings @RequestMapping


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View resolvers AbstractCachingViewResolver

XmlViewResolver

ResourceBundleViewResolver

UrlBasedViewResolver

InternalResourceViewResolver

VelocityViewResolver / FreeMarkerViewResolver

ContentNegotiatingViewResolver


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View resolvers


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CRUD in one place


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REST in Spring MVC Starting Spring 3.1.x

ContentNegotiatingViewResolver

@ResponseBody combined with produces

@RequestBody combined with consumes


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REST in Spring MVC


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Testing MVC Starting from Spring 3.2

spring-test-mvc project

Server-side Spring MVC tests

New Spring Mocks

Different strategies


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Testing MVC


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Testing MVC


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Just to mention Type conversion

Formatter SPI


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Just to mention Type conversion

Formatter SPI


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Just to mention Flash attributes and Redirect attributes


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Spring in 2012


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Just to mention Spring Roo

Spring Hadoop

Spring Android


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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


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Sources http://static.springsource.org/spring/docs/3.1.

x/spring-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/













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Questions?@ua_spring

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Lightweight J2EE development with Spring (special for UADEV)

Technology

spring persistence

spring aop spring aop

aspectj spring aop

java spring config

spring declarative caching

spring expression language

contents spring origins

bean postprocessing