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Spring Framework (Java)
Encyclopedia
The Spring Framework is an open source
application framework
for the Java platform.
The first version was written by Rod Johnson, who released the framework with the publication of his book Expert One-on-One J2EE Design and Development in October 2002. The framework was first released under the Apache 2.0 license
in June 2003. The first milestone release, 1.0, was released in March 2004, with further milestone releases in September 2004 and March 2005. The Spring 1.2.6 framework won a Jolt productivity award
and a JAX Innovation Award in 2006. Spring 2.0 was released in October 2006, and Spring 2.5 in November 2007.
In December 2009 version 3.0 GA was released. The current version is 3.0.6.
The core features of the Spring Framework can be used by any Java application, but there are extensions for building web applications on top of the Java EE platform. Although the Spring Framework does not impose any specific programming model, it has become popular in the Java community as an alternative to, replacement for, or even addition to the Enterprise JavaBean
(EJB) model.
container, which provides a consistent means of configuring and managing Java objects using reflection
. The container is responsible for managing object lifecycles: creating objects, calling initialization methods, and configuring objects by wiring them together.
Objects created by the container are also called Managed Objects or Beans. Typically, the container is configured by loading XML files containing Bean definitions which provide the information required to create the beans.
Objects can be obtained by means of Dependency lookup or Dependency injection
. Dependency lookup is a pattern where a caller asks the container object for an object with a specific name or of a specific type. Dependency injection is a pattern where the container passes objects by name to other objects, via either constructor
s, properties, or factory methods
.
In many cases one need not use the container when using other parts of the Spring Framework, although using it will likely make an application easier to configure and customize. The Spring container provides a consistent mechanism to configure applications and integrates with almost all Java environments, from small-scale applications to large enterprise applications.
The container can be turned into a partially-compliant EJB3 container by means of the Pitchfork project. Some criticize the Spring Framework for not complying with standards. However, SpringSource doesn't see EJB3 compliance as a major goal, and claims that the Spring Framework and the container allow for more powerful programming models.
framework which modularizes cross-cutting concern
s in aspects
. The motivation for creating a separate AOP framework comes from the belief that it would be possible to provide basic AOP features without too much complexity in either design, implementation, or configuration. The Spring AOP framework also takes full advantage of the Spring Container.
The Spring AOP framework is interception based, and is configured at run time. This removes the need for a compilation step or load-time weaving. On the other hand, interception only allows for public method-execution on existing objects at a join point
.
Compared to the AspectJ
framework, Spring AOP is less powerful but also less complicated. Spring 1.2 includes support to configure AspectJ aspects
in the container. Spring 2.0 added more integration with AspectJ; for example, the pointcut
language is reused and can be mixed with SpAOP-based aspects. Further, Spring 2.0 added a Spring Aspects library which uses AspectJ to offer common Spring features such as declarative transaction management and dependency injection via AspectJ compile-time or load-time weaving. SpringSource
also uses AspectJ for AOP in other Spring projects such as Spring Roo
and Spring Insight, with Spring Security also offering an AspectJ-based aspect library.
Spring AOP has been designed to make it able to work with cross-cutting concerns inside the Spring Framework. Any object which is created and configured by the container can be enriched using Spring AOP.
The Spring Framework uses Spring AOP internally for transaction management, security, remote access, and JMX.
Since version 2.0 of the framework, Spring provides two approaches to the AOP configuration:
The Spring team decided not to introduce new AOP-related terminology; therefore, in the Spring reference documentation and API, terms such as aspect
, join point
, advice, pointcut
, introduction, target object (advised object), AOP proxy, and weaving all have the same meanings as in most other AOP frameworks (particularly AspectJ
).
/ MyBatis
, Hibernate
, JDO
, JPA
, Oracle TopLink
, Apache OJB
, and Apache Cayenne
, among others.
For all of these supported frameworks, Spring provides these features
All these features become available when using Template classes provided by Spring for each supported framework. Critics say these Template classes are intrusive and offer no advantage over using (for example) the Hibernate
API.. directly. In response, the Spring developers have made it possible to use the Hibernate and JPA
APIs directly. This however requires transparent transaction management, as application code no longer assumes the responsibility to obtain and close database resources, and does not support exception translation.
Together with Spring's transaction management, its data access framework offers a flexible abstraction for working with data access frameworks. The Spring Framework doesn't offer a common data access API; instead, the full power of the supported APIs is kept intact. The Spring Framework is the only framework available in Java which offers managed data access environments outside of an application server or container.
While using Spring for transaction management with Hibernate, the following beans may have to be configured
Other configurations
In comparison, JTA
only supports nested transaction
s and global transactions
, and requires an application server
(and in some cases also deployment of applications in an application server).
The Spring Framework ships a PlatformTransactionManager for a number of transaction management strategies:
Next to this abstraction mechanism the framework also provides two ways of adding transaction management to applications:
Together with Spring's data access framework — which integrates the transaction management framework — it is possible to set up a transactional system through configuration without having to rely on JTA or EJB. The transactional framework also integrates with messaging
and caching
engines.
framework, which wasn't originally planned. The Spring developers decided to write their own web framework as a reaction to what they perceived as the poor design of the popular Jakarta Struts web framework, as well as deficiencies in other available frameworks. In particular, they felt there was insufficient separation between the presentation and request handling layers, and between the request handling layer and the model.
Like Struts, Spring MVC is a request-based framework. The framework defines strategy
interfaces for all of the responsibilities which must be handled by a modern request-based framework. The goal of each interface is to be simple and clear so that it's easy for Spring MVC users to write their own implementations if they so choose. MVC paves the way for cleaner front end code. All interfaces are tightly coupled to the Servlet API
. This tight coupling to the Servlet API
is seen by some as a failure on the part of the Spring developers to offer a high-level abstraction for web-based applications . However, this coupling makes sure that the features of the Servlet API remain available to developers while offering a high abstraction framework to ease working with said API.
The DispatcherServlet class is the front controller
of the framework and is responsible for delegating control to the various interfaces during the execution phases of a HTTP request
.
The most important interfaces defined by Spring MVC, and their responsibilities, are listed below:
Each strategy
interface above has an important responsibility in the overall framework. The abstractions offered by these interfaces are powerful, so to allow for a set of variations in their implementations, Spring MVC ships with implementations of all these interfaces and together offers a feature set on top of the Servlet API
. However, developers and vendors are free to write other implementations. Spring MVC uses the Java
The ease of testing the implementations of these interfaces seems one important advantage of the high level of abstraction offered by Spring MVC. DispatcherServlet is tightly coupled to the Spring Inversion of Control
container for configuring the web layers of applications. However, web applications can use other parts of the Spring Framework—including the container—and choose not to use Spring MVC.
and AOP
.
The framework also provides fault-recovery (automatic reconnection after connection failure) and some optimizations for client-side use of EJB remote stateless session beans.
Spring provides support for these protocols and products out of the box:
Apache CXF
provides integration with the Spring Framework for RPC-style exporting of object on the server side.
Both client and server setup for all RPC-style protocols and products supported by the Spring Remote access framework (except for the Apache Axis
support) is configured in the Spring Core container.
There is alternative open-source implementation (Cluster4Spring) of a remoting subsystem included into Spring Framework which is intended to support various schemes of remoting (1-1, 1-many, dynamic services discovering).
is Spring's Convention-over-configuration
solution for rapidly building applications in Java
. It currently supports Spring Framework, Spring Security and Spring Web Flow
, with remaining Spring projects scheduled to be added in due course. Roo differs from other rapid application development
frameworks by focusing on:
is a framework for batch processing
that provides reusable functions that are essential in processing large volumes of records, including:
It also provides more advanced technical services and features that will enable extremely high-volume and high performance batch jobs through optimizations and partitioning techniques.
is a framework for Enterprise application integration
that provides reusable functions that are essential in messaging, or event-driven architectures.
Spring Integration supports pipe-and-filter based architectures.
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
application framework
Application framework
In computer programming, an application framework consists of a software framework used by software developers to implement the standard structure of an application for a specific development environment ....
for the Java platform.
The first version was written by Rod Johnson, who released the framework with the publication of his book Expert One-on-One J2EE Design and Development in October 2002. The framework was first released under the Apache 2.0 license
Apache License
The Apache License is a copyfree free software license authored by the Apache Software Foundation . The Apache License requires preservation of the copyright notice and disclaimer....
in June 2003. The first milestone release, 1.0, was released in March 2004, with further milestone releases in September 2004 and March 2005. The Spring 1.2.6 framework won a Jolt productivity award
Jolt Awards
The Jolt Awards are awards in the software industry.Since 1990, the Dr. Dobb's Jolt Product Excellence Awards have been presented annually to showcase products that have "jolted" the industry with their significance and made the task of creating software faster, easier, and more efficient.Jolt Cola...
and a JAX Innovation Award in 2006. Spring 2.0 was released in October 2006, and Spring 2.5 in November 2007.
In December 2009 version 3.0 GA was released. The current version is 3.0.6.
The core features of the Spring Framework can be used by any Java application, but there are extensions for building web applications on top of the Java EE platform. Although the Spring Framework does not impose any specific programming model, it has become popular in the Java community as an alternative to, replacement for, or even addition to the Enterprise JavaBean
Enterprise JavaBean
Enterprise JavaBeans is a managed, server-side component architecture for modular construction of enterprise applications.The EJB specification is one of several Java APIs in the Java EE specification. EJB is a server-side model that encapsulates the business logic of an application...
(EJB) model.
Modules
The Spring Framework comprises several modules that provide a range of services:- Inversion of ControlInversion of ControlIn software engineering, Inversion of Control is an abstract principle describing an aspect of some software architecture designs in which the flow of control of a system is inverted in comparison to procedural programming....
container: configuration of application components and lifecycle management of Java objects - Aspect-oriented programmingAspect-oriented programmingIn computing, aspect-oriented programming is a programming paradigm which aims to increase modularity by allowing the separation of cross-cutting concerns...
: enables implementation of cross-cutting routines - Data accessData accessData access typically refers to software and activities related to storing, retrieving, or acting on data housed in a database or other repository...
: working with relational database management systems on the Java platform using JDBC and object-relational mappingObject-relational mappingObject-relational mapping in computer software 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...
tools and with NoSQLNosqlIn computing, NoSQL is a broad class of database management systems that differ from the classic model of the relational database management system in some significant ways. These data stores may not require fixed table schemas, usually avoid join operations, and typically scale horizontally...
databases - Transaction managementTransaction processingIn computer science, transaction processing is information processing that is divided into individual, indivisible operations, called transactions. Each transaction must succeed or fail as a complete unit; it cannot remain in an intermediate state...
: unifies several transaction management APIs and coordinates transactions for Java objects - Model-view-controllerModel-view-controllerModel–view–controller is a software architecture, currently considered an architectural pattern used in software engineering. The pattern isolates "domain logic" from the user interface , permitting independent development, testing and maintenance of each .Model View Controller...
: an HTTP- and servlet-based framework providing hooks for extension and customization for web applications and RESTRestRest may refer to:* Leisure* Human relaxation* SleepRest may also refer to:* Rest , a pause in a piece of music* Rest , the relation between two observers* Rest , a 2008 album by Gregor Samsa...
ful web services. - Remote Access framework: configurative RPCRemote procedure callIn computer science, a remote procedure call is an inter-process communication that allows a computer program to cause a subroutine or procedure to execute in another address space without the programmer explicitly coding the details for this remote interaction...
-style export and import of Java objects over networks supporting RMIJava remote method invocationThe Java Remote Method Invocation Application Programming Interface , or Java RMI, is a Java application programming interface that performs the object-oriented equivalent of remote procedure calls ....
, CORBAÇorbaChorba , ciorbă , shurpa , shorpo , or sorpa is one of various kinds of soup or stew found in national cuisines across Middle East...
and HTTP-based protocols including web services (SOAP) - Convention-over-configurationConvention over ConfigurationConvention over configuration is a software design paradigm which seeks to decrease the number of decisions that developers need to make, gaining simplicity, but not necessarily losing flexibility....
: a rapid application development solution for Spring-based enterprise applications is offered in the Spring RooSpring RooSpring Roo is an open source software tool that uses convention-over-configuration principles to provide rapid application development of Java-based enterprise software. The resulting applications use common Java technologies such as Spring Framework, Java Persistence API, Java Server Pages, Apache...
module - Batch processingBatch processingBatch processing is execution of a series of programs on a computer without manual intervention.Batch jobs are set up so they can be run to completion without manual intervention, so all input data is preselected through scripts or command-line parameters...
: a framework for high-volume processing featuring reusable functions including logging/tracing, transaction management, job processing statistics, job restart, skip, and resource management - AuthenticationAuthenticationAuthentication is the act of confirming the truth of an attribute of a datum or entity...
and authorizationAuthorizationAuthorization is the function of specifying access rights to resources, which is related to information security and computer security in general and to access control in particular. More formally, "to authorize" is to define access policy...
: configurable security processes that support a range of standards, protocols, tools and practices via the Spring Security sub-project (formerly Acegi Security System for Spring). - Remote Management: configurative exposure and management of Java objects for local or remote configuration via JMX
- Messaging: configurative registration of message listener objects for transparent message-consumption from message queueMessage queueIn computer science, message queues and mailboxes are software-engineering components used for interprocess communication, or for inter-thread communication within the same process. They use a queue for messaging – the passing of control or of content...
s via JMSJava Message ServiceThe Java Message Service API is a Java Message Oriented Middleware API for sending messages between two or more clients. JMS is a part of the Java Platform, Enterprise Edition, and is defined by a specification developed under the Java Community Process as JSR 914...
, improvement of message sending over standard JMS APIs - TestingSoftware testingSoftware testing is an investigation conducted to provide stakeholders with information about the quality of the product or service under test. Software testing can also provide an objective, independent view of the software to allow the business to appreciate and understand the risks of software...
: support classes for writing unit tests and integration tests
Inversion of Control container (Dependency injection)
Central to the Spring Framework is its Inversion of ControlInversion of Control
In software engineering, Inversion of Control is an abstract principle describing an aspect of some software architecture designs in which the flow of control of a system is inverted in comparison to procedural programming....
container, which provides a consistent means of configuring and managing Java objects using reflection
Reflection (computer science)
In computer science, reflection is the process by which a computer program can observe and modify its own structure and behavior at runtime....
. The container is responsible for managing object lifecycles: creating objects, calling initialization methods, and configuring objects by wiring them together.
Objects created by the container are also called Managed Objects or Beans. Typically, the container is configured by loading XML files containing Bean definitions which provide the information required to create the beans.
Objects can be obtained by means of Dependency lookup or Dependency injection
Dependency injection
Dependency injection is a design pattern in object-oriented computer programming whose purpose is to improve testability of, and simplify deployment of components in very large software systems....
. Dependency lookup is a pattern where a caller asks the container object for an object with a specific name or of a specific type. Dependency injection is a pattern where the container passes objects by name to other objects, via either constructor
Constructor (computer science)
In object-oriented programming, a constructor in a class is a special type of subroutine called at the creation of an object. It prepares the new object for use, often accepting parameters which the constructor uses to set any member variables required when the object is first created...
s, properties, or factory methods
Factory method pattern
The factory method pattern is an object-oriented design pattern to implement the concept of factories. Like other creational patterns, it deals with the problem of creating objects without specifying the exact class of object that will be created.The creation of an object often requires complex...
.
In many cases one need not use the container when using other parts of the Spring Framework, although using it will likely make an application easier to configure and customize. The Spring container provides a consistent mechanism to configure applications and integrates with almost all Java environments, from small-scale applications to large enterprise applications.
The container can be turned into a partially-compliant EJB3 container by means of the Pitchfork project. Some criticize the Spring Framework for not complying with standards. However, SpringSource doesn't see EJB3 compliance as a major goal, and claims that the Spring Framework and the container allow for more powerful programming models.
Aspect-oriented programming framework
The Spring Framework has its own AOPAspect-oriented programming
In computing, aspect-oriented programming is a programming paradigm which aims to increase modularity by allowing the separation of cross-cutting concerns...
framework which modularizes cross-cutting concern
Cross-cutting concern
In computer science, cross-cutting concerns are aspects of a program which affect other concerns.These concerns often cannot be cleanly decomposed from the rest of the system in both the design and implementation, and can result in either scattering , tangling , or both.For instance, if writing an...
s in aspects
Aspect (computer science)
In computer science, an aspect of a program is a feature linked to many other parts of the program, but which is not related to the program's primary function. An aspect crosscuts the program's core concerns, therefore violating its separation of concerns that tries to encapsulate unrelated functions...
. The motivation for creating a separate AOP framework comes from the belief that it would be possible to provide basic AOP features without too much complexity in either design, implementation, or configuration. The Spring AOP framework also takes full advantage of the Spring Container.
The Spring AOP framework is interception based, and is configured at run time. This removes the need for a compilation step or load-time weaving. On the other hand, interception only allows for public method-execution on existing objects at a join point
Join point
In computer science, a join point is a point in the control flow of a program. In aspect-oriented programming a set of join points is described as a pointcut...
.
Compared to the AspectJ
AspectJ
AspectJ is an aspect-oriented extension created at PARC for the Java programming language. It is available in Eclipse Foundation open-source projects, both stand-alone and integrated into Eclipse. AspectJ has become the widely-used de-facto standard for AOP by emphasizing simplicity and usability...
framework, Spring AOP is less powerful but also less complicated. Spring 1.2 includes support to configure AspectJ aspects
Aspect (computer science)
In computer science, an aspect of a program is a feature linked to many other parts of the program, but which is not related to the program's primary function. An aspect crosscuts the program's core concerns, therefore violating its separation of concerns that tries to encapsulate unrelated functions...
in the container. Spring 2.0 added more integration with AspectJ; for example, the pointcut
Pointcut
In aspect-oriented computer programming, a pointcut is a set of join points. Whenever the program execution reaches one of the join points described in the pointcut, a piece of code associated with the pointcut is executed. This allows a programmer to describe where and when additional code...
language is reused and can be mixed with SpAOP-based aspects. Further, Spring 2.0 added a Spring Aspects library which uses AspectJ to offer common Spring features such as declarative transaction management and dependency injection via AspectJ compile-time or load-time weaving. SpringSource
SpringSource
SpringSource is a division of VMware that provides a suite of software products that accelerate the entire enterprise Java application life cycle of build, run, and manage. SpringSource employs open source leaders who created and drive innovation for Spring, a programming model for enterprise Java...
also uses AspectJ for AOP in other Spring projects such as Spring Roo
Spring Roo
Spring Roo is an open source software tool that uses convention-over-configuration principles to provide rapid application development of Java-based enterprise software. The resulting applications use common Java technologies such as Spring Framework, Java Persistence API, Java Server Pages, Apache...
and Spring Insight, with Spring Security also offering an AspectJ-based aspect library.
Spring AOP has been designed to make it able to work with cross-cutting concerns inside the Spring Framework. Any object which is created and configured by the container can be enriched using Spring AOP.
The Spring Framework uses Spring AOP internally for transaction management, security, remote access, and JMX.
Since version 2.0 of the framework, Spring provides two approaches to the AOP configuration:
- schema-based approach.
- @AspectJ-based annotation style.
The Spring team decided not to introduce new AOP-related terminology; therefore, in the Spring reference documentation and API, terms such as aspect
Aspect
Aspect may be:*Aspect , a feature that is linked to many parts of a program, but which is not necessarily the primary function of the program...
, join point
Join point
In computer science, a join point is a point in the control flow of a program. In aspect-oriented programming a set of join points is described as a pointcut...
, advice, pointcut
Pointcut
In aspect-oriented computer programming, a pointcut is a set of join points. Whenever the program execution reaches one of the join points described in the pointcut, a piece of code associated with the pointcut is executed. This allows a programmer to describe where and when additional code...
, introduction, target object (advised object), AOP proxy, and weaving all have the same meanings as in most other AOP frameworks (particularly AspectJ
AspectJ
AspectJ is an aspect-oriented extension created at PARC for the Java programming language. It is available in Eclipse Foundation open-source projects, both stand-alone and integrated into Eclipse. AspectJ has become the widely-used de-facto standard for AOP by emphasizing simplicity and usability...
).
Data access framework
Spring's data access framework addresses common difficulties developers face when working with databases in applications. Support is provided for all popular data access frameworks in Java: JDBC, iBatisIBATIS
iBATIS is a persistence framework which automates the mapping between SQL databases and objects in Java, .NET, and Ruby on Rails. In Java, the objects are POJOs . The mappings are decoupled from the application logic by packaging the SQL statements in XML configuration files...
/ MyBatis
MyBatis
MyBatis is a persistence framework available for Java and .NET that couples objects with stored procedures or SQL statements using an XML descriptor or annotations.MyBatis is free software that is distributed under the Apache License 2.0....
, Hibernate
Hibernate (Java)
Hibernate is an object-relational mapping library for the Java language, providing a framework for mapping an object-oriented domain model to a traditional relational database...
, JDO
Java Data Objects
Java Data Objects is a specification of Java object persistence. One of its features is a transparency of the persistent services to the domain model. JDO persistent objects are ordinary Java programming language classes ; there's no requirement for them to implement certain interfaces or extend...
, JPA
Java Persistence API
The Java Persistence API, sometimes referred to as JPA, is a Java programming language framework managing relational data in applications using Java Platform, Standard Edition and Java Platform, Enterprise Edition....
, Oracle TopLink
TopLink
In computing, TopLink is an object-relational mapping package for Java developers. It provides a framework for storing Java objects in a relational database or for converting Java objects to XML documents....
, Apache OJB
Ojb
Apache ObJectRelationalBridge is an Object/Relational mapping tool that allows transparent persistence for Java Objects against relational databases.Apache OJB was released on April 6th, 2005.- Features :* OJB is open source ....
, and Apache Cayenne
Apache Cayenne
Apache Cayenne is an open source persistence framework licensed under the Apache License, providing object-relational mapping and remoting services. Cayenne binds one or more database schemas directly to Java objects, managing atomic commit and rollbacks, SQL generation, joins, sequences, and more...
, among others.
For all of these supported frameworks, Spring provides these features
- Resource management - automatically acquiring and releasing database resources
- Exception handling - translating data access related exception to a Spring data access hierarchy
- Transaction participation - transparent participation in ongoing transactions
- Resource unwrapping - retrieving database objects from connection pool wrappers
- Abstraction for BLOBBlob- In biology :* Blob , sections of the visual cortex where groups of color-sensitive neurons assemble* Globster, an unidentified organic mass that washes up on the shoreline of an ocean or other body of water...
and CLOBCharacter large objectA Character Large Object is a collection of character data in a database management system, usually stored in a separate location that is referenced in the table itself...
handling
All these features become available when using Template classes provided by Spring for each supported framework. Critics say these Template classes are intrusive and offer no advantage over using (for example) the Hibernate
Hibernate (Java)
Hibernate is an object-relational mapping library for the Java language, providing a framework for mapping an object-oriented domain model to a traditional relational database...
API.. directly. In response, the Spring developers have made it possible to use the Hibernate and JPA
Java Persistence API
The Java Persistence API, sometimes referred to as JPA, is a Java programming language framework managing relational data in applications using Java Platform, Standard Edition and Java Platform, Enterprise Edition....
APIs directly. This however requires transparent transaction management, as application code no longer assumes the responsibility to obtain and close database resources, and does not support exception translation.
Together with Spring's transaction management, its data access framework offers a flexible abstraction for working with data access frameworks. The Spring Framework doesn't offer a common data access API; instead, the full power of the supported APIs is kept intact. The Spring Framework is the only framework available in Java which offers managed data access environments outside of an application server or container.
While using Spring for transaction management with Hibernate, the following beans may have to be configured
- DataSource like
com.mchange.v2.c3p0.ComboPooledDataSourceororg.apache.commons.dbcp.BasicDataSource - SessionFactory like
org.springframework.orm.hibernate3.LocalSessionFactoryBeanwith a DataSource attribute - HibernateProperties like
org.springframework.beans.factory.config.PropertiesFactoryBean - TransactionManager like
org.springframework.orm.hibernate3.HibernateTransactionManagerwith a SessionFactory attribute
Other configurations
- AOP configuration of cutting points using
- Transaction semantics of AOP advice using
Transaction management framework
Spring's transaction management framework brings an abstraction mechanism to the Java platform. Its abstraction is capable of:- working with local and global transactionsDistributed transactionA distributed transaction is an operations bundle, in which two or more network hosts are involved. Usually, hosts provide transactional resources, while the transaction manager is responsible for creating and managing a global transaction that encompasses all operations against such resources...
(local transaction does not require an application serverApplication serverAn application server is a software framework that provides an environment in which applications can run, no matter what the applications are or what they do...
) - working with nested transactionNested transactionWith reference to a database transaction, a nested transaction occurs when a new transaction is started by an instruction that is already inside an existing transaction. The new transaction is said to be nested within the existing transaction, hence the term....
s - working with transaction safepoints
- working in almost all environments of the Java platform
In comparison, JTA
Java Transaction API
The Java Transaction API is one of the Java Enterprise Edition APIs allowing distributed transactions to be done across multiple XA resources in a Java environment. JTA is a specification developed under the Java Community Process as JSR 907...
only supports nested transaction
Nested transaction
With reference to a database transaction, a nested transaction occurs when a new transaction is started by an instruction that is already inside an existing transaction. The new transaction is said to be nested within the existing transaction, hence the term....
s and global transactions
Distributed transaction
A distributed transaction is an operations bundle, in which two or more network hosts are involved. Usually, hosts provide transactional resources, while the transaction manager is responsible for creating and managing a global transaction that encompasses all operations against such resources...
, and requires an application server
Application server
An application server is a software framework that provides an environment in which applications can run, no matter what the applications are or what they do...
(and in some cases also deployment of applications in an application server).
The Spring Framework ships a PlatformTransactionManager for a number of transaction management strategies:
- Transactions managed on a JDBC Connection
- Transactions managed on Object-relational mappingObject-relational mappingObject-relational mapping in computer software 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...
Units of Work - Transactions managed via the JTA TransactionManager and UserTransaction
- Transactions managed on other resources, like object databaseObject databaseAn object database is a database management system in which information is represented in the form of objects as used in object-oriented programming...
s
Next to this abstraction mechanism the framework also provides two ways of adding transaction management to applications:
- Programmatically, by using Spring's TransactionTemplate
- Configuratively, by using metadataMetadataThe term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
like XML or Java 5 annotationAnnotationAn annotation is a note that is made while reading any form of text. This may be as simple as underlining or highlighting passages.Annotated bibliographies give descriptions about how each source is useful to an author in constructing a paper or argument...
s
Together with Spring's data access framework — which integrates the transaction management framework — it is possible to set up a transactional system through configuration without having to rely on JTA or EJB. The transactional framework also integrates with messaging
Java Message Service
The Java Message Service API is a Java Message Oriented Middleware API for sending messages between two or more clients. JMS is a part of the Java Platform, Enterprise Edition, and is defined by a specification developed under the Java Community Process as JSR 914...
and caching
Cache
In computer engineering, a cache is a component that transparently stores data so that future requests for that data can be served faster. The data that is stored within a cache might be values that have been computed earlier or duplicates of original values that are stored elsewhere...
engines.
Model-view-controller framework
The Spring Framework features its own MVCModel-view-controller
Model–view–controller is a software architecture, currently considered an architectural pattern used in software engineering. The pattern isolates "domain logic" from the user interface , permitting independent development, testing and maintenance of each .Model View Controller...
framework, which wasn't originally planned. The Spring developers decided to write their own web framework as a reaction to what they perceived as the poor design of the popular Jakarta Struts web framework, as well as deficiencies in other available frameworks. In particular, they felt there was insufficient separation between the presentation and request handling layers, and between the request handling layer and the model.
Like Struts, Spring MVC is a request-based framework. The framework defines strategy
Strategy pattern
In computer programming, the strategy pattern is a particular software design pattern, whereby algorithms can be selected at runtime. Formally speaking, the strategy pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable...
interfaces for all of the responsibilities which must be handled by a modern request-based framework. The goal of each interface is to be simple and clear so that it's easy for Spring MVC users to write their own implementations if they so choose. MVC paves the way for cleaner front end code. All interfaces are tightly coupled to the Servlet API
Java Servlet
A servlet is a Java programming language class used to extend the capabilities of servers that host applications accessed via a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by Web servers...
. This tight coupling to the Servlet API
Java Servlet
A servlet is a Java programming language class used to extend the capabilities of servers that host applications accessed via a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by Web servers...
is seen by some as a failure on the part of the Spring developers to offer a high-level abstraction for web-based applications . However, this coupling makes sure that the features of the Servlet API remain available to developers while offering a high abstraction framework to ease working with said API.
The DispatcherServlet class is the front controller
Front Controller pattern
The Front Controller Pattern is a software design pattern listed in several pattern catalogs. The pattern relates to the design of web applications. It "provides a centralized entry point for handling requests."...
of the framework and is responsible for delegating control to the various interfaces during the execution phases of a HTTP request
Hypertext Transfer Protocol
The Hypertext Transfer Protocol is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web....
.
The most important interfaces defined by Spring MVC, and their responsibilities, are listed below:
- HandlerMapping: selecting objects which handle incoming requests (handlers) based on any attribute or condition internal or external to those requests
- HandlerAdapter: execution of objects which handle incoming requests
- Controller: comes between Model and View to manage incoming requests and redirect to proper response. It essentially is like a gate that directs the incoming information. It switches between going into model or view.
- View: responsible for returning a response to the client. It is possible to go straight to view without going to the model part. It is also possible to go through all three.
- ViewResolver: selecting a View based on a logical name for the view (use is not strictly required)
- HandlerInterceptor: interception of incoming requests comparable but not equal to ServletJava ServletA servlet is a Java programming language class used to extend the capabilities of servers that host applications accessed via a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by Web servers...
filters (use is optional and not controlled by DispatcherServlet). - LocaleResolver: resolving and optionally saving of the localeLocaleIn computing, locale is a set of parameters that defines the user's language, country and any special variant preferences that the user wants to see in their user interface...
of an individual user - MultipartResolver: facilitate working with file uploads by wrapping incoming requests
Each strategy
Strategy pattern
In computer programming, the strategy pattern is a particular software design pattern, whereby algorithms can be selected at runtime. Formally speaking, the strategy pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable...
interface above has an important responsibility in the overall framework. The abstractions offered by these interfaces are powerful, so to allow for a set of variations in their implementations, Spring MVC ships with implementations of all these interfaces and together offers a feature set on top of the Servlet API
Java Servlet
A servlet is a Java programming language class used to extend the capabilities of servers that host applications accessed via a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by Web servers...
. However, developers and vendors are free to write other implementations. Spring MVC uses the Java
java.util.Map interface as a data-oriented abstraction for the Model where keys are expected to be string values.The ease of testing the implementations of these interfaces seems one important advantage of the high level of abstraction offered by Spring MVC. DispatcherServlet is tightly coupled to the Spring Inversion of Control
Inversion of Control
In software engineering, Inversion of Control is an abstract principle describing an aspect of some software architecture designs in which the flow of control of a system is inverted in comparison to procedural programming....
container for configuring the web layers of applications. However, web applications can use other parts of the Spring Framework—including the container—and choose not to use Spring MVC.
Remote access framework
Spring's Remote Access framework is an abstraction for working with various RPC-based technologies available on the Java platform both for client connectivity and exporting objects on servers. The most important feature offered by this framework is to ease configuration and usage of these technologies as much as possible by combining Inversion of ControlInversion of Control
In software engineering, Inversion of Control is an abstract principle describing an aspect of some software architecture designs in which the flow of control of a system is inverted in comparison to procedural programming....
and AOP
Aspect-oriented programming
In computing, aspect-oriented programming is a programming paradigm which aims to increase modularity by allowing the separation of cross-cutting concerns...
.
The framework also provides fault-recovery (automatic reconnection after connection failure) and some optimizations for client-side use of EJB remote stateless session beans.
Spring provides support for these protocols and products out of the box:
- HTTPHypertext Transfer ProtocolThe Hypertext Transfer Protocol is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web....
-based protocols- HessianHessian (web service protocol)Hessian is a binary web service protocol that makes web services usable without requiring a large framework, and without learning a new set of protocols. Because it is a binary protocol, it is well-suited to sending binary data without any need to extend the protocol with attachments.Hessian was...
: binary serialization protocol, open-sourced and maintained by CORBACommon Object Request Broker ArchitectureThe Common Object Request Broker Architecture is a standard defined by the Object Management Group that enables software components written in multiple computer languages and running on multiple computers to work together .- Overview:CORBA enables separate pieces of software written in different...
-based protocols - RMIJava remote method invocationThe Java Remote Method Invocation Application Programming Interface , or Java RMI, is a Java application programming interface that performs the object-oriented equivalent of remote procedure calls ....
(1): method invocations using RMI infrastructure yet specific to Spring - RMIJava remote method invocationThe Java Remote Method Invocation Application Programming Interface , or Java RMI, is a Java application programming interface that performs the object-oriented equivalent of remote procedure calls ....
(2): method invocations using RMI interfaces complying with regular RMI usage - RMI-IIOPRMI-IIOPRMI-IIOP denotes the Java Remote Method Invocation interface over the Internet Inter-Orb Protocol , which delivers Common Object Request Broker Architecture distributed computing capabilities to the Java 2 platform...
(CORBACommon Object Request Broker ArchitectureThe Common Object Request Broker Architecture is a standard defined by the Object Management Group that enables software components written in multiple computer languages and running on multiple computers to work together .- Overview:CORBA enables separate pieces of software written in different...
): method invocations using RMI-IIOP/CORBA
- Hessian
- Enterprise JavaBeanEnterprise JavaBeanEnterprise JavaBeans is a managed, server-side component architecture for modular construction of enterprise applications.The EJB specification is one of several Java APIs in the Java EE specification. EJB is a server-side model that encapsulates the business logic of an application...
client integration- Local EJB stateless session bean connectivity: connecting to local stateless session beans
- Remote EJB stateless session bean connectivity: connecting to remote stateless session beans
- SOAP
- Integration with the Apache AxisApache AxisApache Axis is an open source, XML based Web service framework. It consists of a Java and a C++ implementation of the SOAP server, and various utilities and APIs for generating and deploying Web service applications. Using Apache Axis, developers can create interoperable, distributed computing...
web services framework
- Integration with the Apache Axis
Apache CXF
Apache CXF
Apache CXF is an open-source, fully featured Web services framework. It originated as the combination of two open-source projects: Celtix developed by IONA Technologies and XFire developed by a team hosted at Codehaus. These two projects were combined by people working together at the Apache...
provides integration with the Spring Framework for RPC-style exporting of object on the server side.
Both client and server setup for all RPC-style protocols and products supported by the Spring Remote access framework (except for the Apache Axis
Apache Axis
Apache Axis is an open source, XML based Web service framework. It consists of a Java and a C++ implementation of the SOAP server, and various utilities and APIs for generating and deploying Web service applications. Using Apache Axis, developers can create interoperable, distributed computing...
support) is configured in the Spring Core container.
There is alternative open-source implementation (Cluster4Spring) of a remoting subsystem included into Spring Framework which is intended to support various schemes of remoting (1-1, 1-many, dynamic services discovering).
Convention-Over-Configuration Rapid Application Development
Spring RooSpring Roo
Spring Roo is an open source software tool that uses convention-over-configuration principles to provide rapid application development of Java-based enterprise software. The resulting applications use common Java technologies such as Spring Framework, Java Persistence API, Java Server Pages, Apache...
is Spring's Convention-over-configuration
Convention over Configuration
Convention over configuration is a software design paradigm which seeks to decrease the number of decisions that developers need to make, gaining simplicity, but not necessarily losing flexibility....
solution for rapidly building applications in Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
. It currently supports Spring Framework, Spring Security and Spring Web Flow
Spring Web Flow
Spring Web Flow is the sub-project of the Spring Framework that focuses on providing the infrastructure for building and running rich web applications...
, with remaining Spring projects scheduled to be added in due course. Roo differs from other rapid application development
Rapid application development
Rapid application development is a software development methodology that uses minimal planning in favor of rapid prototyping. The "planning" of software developed using RAD is interleaved with writing the software itself...
frameworks by focusing on:
- Java platform productivity (as opposed to other languages)
- Usability (particularly via the shell features and usage patterns)
- Runtime avoidance (with associated deployment advantages)
- Lock-in avoidance (Roo can be removed within a few minutes from any application)
- Extensibility (via add-ons)
Batch Framework
Spring BatchSpring Batch
Spring Batch is an open source framework for batch processing. It is a lightweight, comprehensive solution designed to enable the development of robust batch applications vital for the daily operations of enterprise systems...
is a framework for batch processing
Batch processing
Batch processing is execution of a series of programs on a computer without manual intervention.Batch jobs are set up so they can be run to completion without manual intervention, so all input data is preselected through scripts or command-line parameters...
that provides reusable functions that are essential in processing large volumes of records, including:
- logging/tracing
- transaction management
- job processing statistics
- job restart
- skip
- resource management
It also provides more advanced technical services and features that will enable extremely high-volume and high performance batch jobs through optimizations and partitioning techniques.
Integration Framework
Spring IntegrationSpring Integration
Spring Integration is an open source framework for Enterprise application integration. It is a lightweight framework that builds upon the core Spring framework. It is designed to enable the development of integration solutions typical of event-driven architectures and messaging-centric...
is a framework for Enterprise application integration
Enterprise application integration
Enterprise Application Integration is defined as the use of software and computer systems architectural principles to integrate a set of enterprise computer applications.- Overview :...
that provides reusable functions that are essential in messaging, or event-driven architectures.
- routers
- transformers
- adapters to integrate with other technologies and systems (HTTP, AMQP, JMSJMS- Buildings :*EverBank Field, a sports stadium in Jacksonville, Florida, home of the Jacksonville Jaguars. Formerly known as Jacksonville Municipal Stadium...
, XMPP, SMTP, IMAP, FTP (as well as FTPS/SFTP), file systems, etc.) - filters
- service activators
- management and auditing
Spring Integration supports pipe-and-filter based architectures.