1. Enterprise Application Development Sadegh Aliakbary An Introduction to Spring Framework www. JavaCup.ir

2. 2  Copyright ©2014 JAVACUP.ir  All rights reserved.  Redistribution of JAVACUP contents is not prohibited if JAVACUP is clearly noted as the source in the used case.  JAVACUP shall not be liable for any errors in the content, or for any actions taken in reliance thereon.  Please send your feedback to info@javacup.irinfo@javacup.ir JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source

3. Outline  Dependency Injection and IoC  Aspect Oriented Programming  Spring Framework  Spring vs. EJB 3JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source

4. Introduction to Spring Framework JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 4  An open source Java platform  Initially written by Rod Johnson, first released under the Apache 2.0 license in June 2003  Spring is lightweight: the basic version = 2MB  The core features can be used in any Java application  But there are extensions for web applications on top of Java EE platform  Spring targets to make J2EE development easier to use  Promote good programming practice  By enabling a POJO-based programming model

5. About Spring JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 5  Provides to create high performing, easily testable and  reusable code.  is organized in a modular fashion  simplifies java development

6. Spring Modules JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 6  Spring is modular  Allowing you to choose which modules are applicable to you  Provides about 20 modules

7. JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 7

8. Spring Modules (cont’d) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 8

9. Two Key Components of Spring JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 9  Dependency Injection (DI)  Aspect Oriented Programming (AOP)

10. Dependency Injection (DI) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 10  Inversion of Control (IoC)  Object coupling is bound at run time  The binding process is achieved through dependency injection  Some argue that a “service locator” also provides IoC  Dependency injection is a software design pattern  DI allows the removal of hard-coded dependencies  Makes it possible to change them at run-time  E.g.  as a simple way to load plugins dynamically  to choose stubs or mock objects in test environments vs. real objects in production environments.

11. Dependency Injection (cont’d) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 11  application classes should be as independent as possible  To increase the possibility to reuse these classes  and to test them independently  Dependency: an association between two classes  E.g., class A is dependent on class B  Injection: class B will get injected into class A by the IoC  Dependency injection  in the way of passing parameters to the constructor  or by post-construction using setter methods

12. Aspect Oriented Programming (AOP) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 12  cross-cutting concerns  The functions that span multiple points of an application  cross-cutting concerns are conceptually separate from the application's business logic  E.g., logging, declarative transactions, security, and caching  The key unit of modularity  in OOP: the class  in AOP: the aspect.  DI helps you decouple application objects from each other  AOP helps you decouple cross-cutting concerns from the objects that they affect

13. Spring vs. EJB JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 13  Spring is light-weight  And portable  Offers many features of EJBs  But simpler and easier  No need to application server  Core features: non-web applications  Spring integrates many existing frameworks  ORM frameworks, logging frameworks, JEE, Quartz and JDK timers, other view technologies

14. Spring vs. EJB (cont’d) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 14  Testing is simpler  Testing in non-web contexts  Injection of mock objects  Lightweight IoC containers  a consistent transaction management interface  scale down to a local transaction  using a single database  scale up to global transactions  using JTA

15. What is Spring? JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 15  Spring is the most popular application development framework for enterprise Java

16. Trends: Spring vs. EJB JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 16

17. Spring Setup JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 17  Spring is some jar files  Download from: http://www.springsource.org/spring-community-download http://www.springsource.org/spring-community-download  And dependencies to some others  Apache Common Logging API  Download from: http://commons.apache.org/logging/http://commons.apache.org/logging/  AspectJ  aspectjrt.jar  aspectjweaver.jar  aspectj.jar  Aopalliance.jar

18. Spring – Hello World JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 18  Create your java project  Simple application  Web application  Add required Jar libraries  Create source files  Class of beans  Create bean configuration file (XML)  Retrieve beans

19. Source: Bean Classes JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 19

20. Bean Configuration File JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 20

21. Retrieve Beans JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 21

22. Spring Container JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 22

23. Spring Configuration Metadata JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 23  XML based configuration file.  Annotation-based configuration  Java-based configuration

24. Spring IoC Containers (cont’d) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 24  Spring BeanFactory Container  the simplest container providing basic support for DI  for the purposes of backward compatibility  E.g.  XmlBeanFactory factory = new XmlBeanFactory (new ClassPathResource("Beans.xml"));  Spring ApplicationContext Container  This container adds more enterprise-specific functionality  E.g.  ApplicationContext context = new FileSystemXmlApplicationContext ("C:/Beans.xml");

25. Spring Bean Definition JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 25  class  name (id)  scope  constructor-arg  properties  autowiring mode  lazy-initialization mode  initialization method  A callback, invoked just after all properties on the bean have been set  For the sake of post-processing the bean creation  destruction method  A callback, invoked when the container is destroyed.

26. Spring Bean Scopes JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 26  Common Scopes  singleton  prototype  container creates new bean instance of the object every time a request for that specific bean is made.  Web-aware applications  request  session  global-session

27. Hint JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 27  Think about it:  Spring bean container is not a web framework  How a servlet container may prepare web-contexts (request, session and global-session) for beans?  Listeners

28. Note JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 28  Singleton pattern:  singleton per class-loader  Singleton in Spring:  singleton per bean definition, per container

29. Default initialization and destroy methods JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 29

30. Bean Example JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 30

31. Bean Definition Inheritance JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 31  Parent property for beans

32. Bean Definition Inheritance (cont’d) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 32  Abstract beans  Bean Definition Template

33. Note JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 33  Relation of parent and abstract to OOP concepts?  Inheritance in Spring is different from OOP inheritance  Parent has a different meaning  Abstract in Spring is different from OOP abstract  Parent and abstract is defined for beans (objects) not for classes

34. Dependency Injection JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 34  Every java based application has a few objects that work together  In a complex Java application, application classes should be as independent as possible  To increase the possibility to reuse these classes  and to test them independently  Dependency Injection (or sometime called wiring) helps in gluing these classes together  and same time keeping them independent.

35. Example of a Dependency: JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 35  What is wrong with this code?  we have created a dependency between the TextEditor and the SpellChecker concrete class

36. Solution JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 36  inversion of control  like this:

37. Dependency Injection Types JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 37  Constructor-based dependency injection  Setter-based dependency injection

38. Constructor-based dependency injection JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 38

39. Constructor-based dependency injection (2) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 39

40. Constructor-based dependency injection (3) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 40

41. Constructor-based dependency injection (4) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 41  Perhaps the best way

42. Setter-based JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 42

43. XML Configuration using p-namespace JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 43

44. Injecting Collections (list) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 44

45. Injecting Collections (set) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 45

46. Injecting Collections (map) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 46

47. Injecting Collections (properties) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 47

48. Injecting references in Collections JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 48

49. Inner Beans JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 49  Defined within the scope of another bean  a element inside the or elements  Similar to inner classes, but:  It is all about the scope of beans, nothing about OOP

50. Injecting null and empty string values JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 50

51. Auto-wiring JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 51  We can autowire relationships between collaborating beans  Without using or elements  Decreases the amount of XML configuration you write  Use the autowire attribute of the element  no  byName  byType  constructor

52. Auto-wiring : byName JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 52  Autowiring by property name.  Spring looks at the properties of the beans on which autowire attribute is set to byName  Tries to match and wire its properties with the beans defined by the same names  If matches are not found, it will throw exceptions

53. Auto-wiring : byType JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 53  Autowiring by property datatype  Spring looks at the properties of the beans on which autowire attribute is set to byType  Tries to match and wire a property if its type matches with exactly one of the beans  If more than one such beans exists, a fatal exception is thrown

54. Auto-wiring : constructor JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 54  Similar to byType  but type applies to constructor arguments  If there is not exactly one bean of the constructor argument type in the container, a fatal error is raised

55. Limitations with autowiring JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 55

56. Annotation Based Configuration JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 56  Since Spring 2.5  to configure the dependency injection using annotations  instead of using XML to describe a bean wiring  move the bean configuration into the component class itself by using annotations

57. Annotation-based Configuration Examples JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 57

58. Spring Java Based Configuration JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 58  To write most of your Spring configuration without XML  But with few Java-based annotations  @Configuration: the class can be used by the Spring IoC container as a source of bean definitions  Instead of writing xml files  @Bean: the annotated method will return an object that should be registered as a bean in the Spring application context  Instead of writing tags

59. Example JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 59  Above code will be equivalent to the following XML configuration:

60. Creating the Context JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 60

61. Injecting Bean Dependencies JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 61

62. AOP with Spring Framework JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 62  Aspect oriented programming  cross-cutting concerns  logging, auditing, declarative transactions, security, and caching  The key unit of modularity in OOP is the class  in AOP the unit of modularity is the aspect  Dependency Injection helps you decouple your application objects from each other  AOP helps you decouple cross-cutting concerns from the objects that they affect  AOP is like triggers  Spring AOP module provides interceptors  for example, when a method is executed  you can add extra functionality before or after the method execution

63. AOP Terminology JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 63  Aspect  A module which has APIs providing cross-cutting requirements  E.g., a logging module  Join point  the actual place in the application where an action will be taken  E.g., before deposit() method  Advice  the actual action to be taken  Point-cut  a set of one or more join-points where an advice should be executed  Expressed using expressions or patterns

64. AOP Terminology (2) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 64  Introduction  to add new methods or attributes to existing classes  Target object  The object being advised by one or more aspects  will always be a proxied object  Also referred to as the advised object  Weaving  The process of linking aspects with other application types or objects, to create an advised object  This can be done at compile time, load time, or at runtime.

65. Types of Advice JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 65  before  before the a method execution  after  around  before and after  after-returning  only if method completes successfully  after-throwing  only if method exits by throwing an exception

66. XML Schema Based AOP with Spring JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 66

67. AOP Needed jars: JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 67  aspectjrt.jar  aspectjweaver.jar  aspectj.jar  aopalliance.jar

68. Example: AOP in Spring JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 68

69. Annotation-based Aspects JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 69  enabled by including inside XML Schema-based configuration file  The actual body of the businessService() is irrelevant  should be empty

70. Spring JDBC Framework JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 70  Simplifies JDBC programming  Takes care of all the low-level details  opening the connection  prepare and execute the SQL statement  process exceptions  handle transactions  finally close the connection

71. DataSource JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 71 <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://localhost:3306/test" />

72. JDBCTemplate Class JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 72  executes SQL queries  update statements  stored procedure calls  performs iteration over ResultSets and extraction of returned parameter values  Instances of the JdbcTemplate class are threadsafe  single instance of a JdbcTemplate is sufficient  safely inject this shared reference into multiple DAOs

73. JDBCTemplate Examples JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 73 String SQL = "select count(*) from Student"; int rowCount = jdbcTemplateObject.queryForInt( SQL ); String SQL = "select age from Student where id = ?"; int age = jdbcTemplateObject.queryForInt(SQL, new Object[]{10}); String SQL = "select name from Student where id = ?"; String name = jdbcTemplateObject.queryForObject( SQL, new Object[]{10}, String.class);

74. JDBCTemplate Examples (cont’d) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 74 String SQL = "select * from Student where id = ?"; Student student = jdbcTemplateObject.queryForObject( SQL, new Object[]{10}, new StudentMapper());

75. Data Access Object (DAO) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 75  DAOs provide a means to read/write data to the database

76. Student DAO (Cont’d) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 76

77. Spring Transaction Management JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 77  A database transaction is a sequence of actions that are treated as a single unit of work  four key properties described as ACID  Atomicity  Consistency  Isolation  Durability  Local vs. Global Transactions  Programmatic vs. Declarative  Declarative: annotations or XML based configuration  Declarative transaction management is preferable  Spring supports declarative transaction management through AOP

78. Programmatic Transaction Management JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 78

79. JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 79

80. Declarative Transaction Management JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 80  Use Advices which creates a transaction-handling advice  tag  Define a pointcut that matches all methods we wish to make transactional  Reference the transactional advice  If a method name has been included in the transactional configuration then created advice will begin the transaction before calling the method  Target method will be executed in a try / catch block.  If the method finishes normally, the AOP advice commits the transaction successfully otherwise it performs a rollback

81. Spring’s Declarative Transaction Management JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 81

82. Bean Configuration for Transactions JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 82

83. Using @Transactional JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 83  You can use @Transactional for methods or Classes

84. Spring Framework Alternatives JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 84  Google Guice  provides support for dependency injection using annotations  Java EE 6 new standards  Contexts and Dependency Injection (CDI)  specified by JSR 299  JBoss Weld is its reference implementation  CDI: a JCP specification included in Java EE 6 (JSR 299)  Weld: the reference implementation of CDI  Seam 3: a set of modules which extend CDI to provide functionality beyond that offered by Java EE 6  Red Hat  JBoss  Seam Framwork  Weld

85. Decision point JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 85  Standards or (non-standard) frameworks?  The benefits of standard technologies  Standards  JSP, JSF, JPA, …  Non-standard technologies  Spring, GWT, …

86. JavaEE6’s Advocates Say: JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 86  The Age of Frameworks is Over  The J2EE platform had its shortcoming  Spring quickly became the most prominent framework for easily building enterprise-ready applications  Helping developers avoid many of the pitfalls of the old enterprise Java platform  But J2EE represents the past, and Java EE 6 represents the future!  Java EE 6 promises us the ability to go beyond frameworks.

87. JavaEE6’s Advocates Say: (cont’d) JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 87  Frameworks like Spring are really just a bridge between the mistakes of the J2EE past and the success of the Java EE 6 future.  Frameworks are out, and extensions to the Java EE 6 platform are in.  Now is the time to start looking past Spring, and looking forward to Seam and Weld and CDI technologies.  And to start shifting into a world of extensions, and moving away from frameworks,

88. But, Spring’s Advocates Say: JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 88  In fact, Spring is more than a DI framework  Perhaps, it is still the most popular application development framework for enterprise Java  Many extensions for easy integration with other frameworks

89. Review a Real Application JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 89  Beans for data access (DAO)  E.g., Hibernate or JDBC classes  Beans for business logic  Beans for presentation  E.g., GWT or JSF pages  How are the dependencies?  How are the beans retrieved from bean container?  How many beans:  Data-sources?  DAOs?  Logic classes?  Presentation classes?

90. Exercise JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 90  Write a web application  “Add” and “List” forms for telephone contacts  With all layers  Dao  Business logic  Presentation  Define the beans and spring-enable your project

91. References and Material JAVACUP.irContents redistribution is allowed if JAVACUP is noted as the source 91  Spring Framework Reference Documentation  http://www.springsource.org/documentation http://www.springsource.org/documentation  Spring Framework 3.1 Tutorial  www.tutorialspoint.com/spring/spring_tutorial.pdf www.tutorialspoint.com/spring/spring_tutorial.pdf