| Spring Framework | |
|---|---|
 | |
| Developer(s) | VMware |
| Initial release | 1 October 2002; 22 years ago (2002-10-01) |
| Stable release | |
| Repository | |
| Written in | Java |
| Platform | Java EE |
| Type | Application framework |
| License | Apache License 2.0 |
| Website | spring |
TheSpring Framework is anapplication framework andinversion of controlcontainer for theJava platform.[2] The framework's core features can be used by any Java application, but there are extensions for buildingweb applications on top of theJava EE (Enterprise Edition) platform. The framework does not impose any specificprogramming model.[citation needed]. The framework has become popular in the Java community as an addition to theEnterprise JavaBeans (EJB) model.[3] The Spring Framework isfree and open source software.[4]: 121–122 [5]
| Version | Date |
|---|---|
| 0.9 | 2003 |
| 1.0 | March 24, 2004 |
| 2.0 | 2006 |
| 3.0 | 2009 |
| 4.0 | 2013 |
| 5.0 | 2017 |
| 6.0 | November 22, 2022 |
| 6.1 | November 16, 2023 |
| 6.2 | November 14, 2024 |
The first version was written byRod Johnson, who released the framework with the publication of his bookExpert One-on-One J2EE Design and Development in October 2002. The framework was first released under theApache 2.0 license in June 2003. The first production release, 1.0, was released in March 2004.[6] The Spring 1.2.6 framework won aJolt productivity award and aJAX Innovation Award in 2006.[7][8] Spring 2.0 was released in October 2006, Spring 2.5 in November 2007, Spring 3.0 in December 2009, Spring 3.1 in December 2011, and Spring 3.2.5 in November 2013.[9] Spring Framework 4.0 was released in December 2013.[10] Notable improvements in Spring 4.0 included support for Java SE (Standard Edition) 8,Groovy 2,[11][12] some aspects of Java EE 7, andWebSocket.[13]
Spring Framework 4.2.0 was released on 31 July 2015 and was immediately upgraded to version 4.2.1, which was released on 01 Sept 2015.[14] It is"compatible with Java 6, 7 and 8, with a focus on core refinements and modern web capabilities".[15]
Spring Framework 4.3 has been released on 10 June 2016 and was supported until 2020.[16] It was announced to"be the final generation within the general Spring 4 system requirements (Java 6+, Servlet 2.5+), [...]".[15]
Spring 5 is announced to be built uponReactive Streams compatible Reactor Core.[17][obsolete source]
Spring Framework 6.0 has been released on 16 November 2022 and came with a Java 17+ baseline and a move to Jakarta EE 9+ (in thejakarta namespace), with a focus on the recently released Jakarta EE 10APIs such as Servlet 6.0 and JPA 3.1.[18]
The Spring Framework includes several modules that provide a range of services:
BeanFactory andApplicationContext).[20][21][22] In this context,spring-core is the artifact[23] found in the core module[24] belonging to theorg.springframework group.[25] Thespring-core artifact consists of the IoC container, as well as the utility classes[23] used throughout the application.[26]spring-aop is an artifact for the AOP framework.[24]spring-jdbc is an artifact found in the JDBC module which supports JDBC access by including datasource setup classes.[24]spring-websocket.spring-oxm.Spring modules are packaged as JAR files.[46] These artifacts can be accessed via the Maven Central Repository usingMaven[47] orGradle.[48]
Theinversion of control (IoC) container is the core container in the Spring Framework.[2] It provides a consistent means of configuring and managing Java objects[2][4]: 127–131 usingreflection.[49] The container is responsible for managingobject lifecycles of specific objects:[4]: 128 creating these objects,[50] calling theirinitialization methods,[49] and configuring these objects by wiring them together.[51]
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[4]: 122 and integrates with almost all Java environments, from small-scale applications to large enterprise applications.
The programmer does not directly create an object, but describes how it should be created, by defining it in the Spring configuration file. Similarly, services and components are not called directly; instead a Spring configuration file defines which services and components must be called. This IoC is intended to increase the ease of maintenance and testing.
Objects created by the container are called managed objects orbeans.[52] The container can be configured by loadingXML (Extensible Markup Language) files[50][4]: 151–152 or detecting specificJava annotations on configuration classes. These data sources contain the bean definitions that provide the information required to create the beans.
The@Configuration is a Spring-specific annotation that marks a class as the configuration class. The configuration class provides the beans to the SpringApplicationContext.[53] Each of the methods in the Spring configuration class is configured with the@Bean annotation. TheApplicationContext interface will then return the objects configured with the@Bean annotation as beans. The advantage of Java-based configuration over XML-based configuration is better type safety and refactorability.[53]
There are several types of Inversion of Control. Dependency injection and dependency lookup are examples of Inversion of Control.[54] Objects can be obtained by means of either dependency lookup or dependency injection.[4]: 127 [55]
Dependency injection is a pattern where the container passes objects[4]: 128 by name to other objects, via eitherconstructors,[4]: 128 properties, orfactory methods. There are several ways to implement dependency injection: constructor-based dependency injection, setter-based dependency injection and field-based dependency injection.[56]
Dependency lookup is a pattern where a caller asks the container object for an object with a specific name or of a specific type.
The Spring framework has a feature known as autowiring, which uses the Spring container to automatically satisfy the dependencies specified in the JavaBean properties to objects of the appropriate type in the current factory.[57] This can only occur if there is only one object with the appropriate type.[57]
There are several annotations that can be used for autowiring POJOs, including the Spring-specific annotation@Autowire (as well as several other Spring-specific annotations that help resolve autowire ambiguity such as the@Qualifier or@Primary annotations),[58][59] and the standard Java annotations@Resource and@Inject.[60]
The@Qualifier annotation can be used on a class that defines a bean to inform Spring to prioritize the bean creation when autowiring it byname.[59]
The@Primary annotation can be used on a class that defines a bean to inform Spring to prioritize the bean creation when autowiring it bytype.[59]
The@Resource annotation is an annotation that conforms toJSR 250, or Common Annotations for the Java Platform, and is used for autowiring references to POJOs byname.[60]
The@Inject annotation is an annotation that conforms to JSR 300, or Standard Annotations for injection, and is used for autowiring references to POJOs bytype.[60]
The Spring Framework has its ownAspect-oriented programming (AOP) framework that modularizes cross-cutting concerns inaspects.[61] The motivation for creating a separate AOP framework is to provide basic AOP features without too much complexity in either design, implementation, or configuration. The Spring AOP framework takes full advantage of the Spring container.
The Spring AOP framework isproxy pattern-based.[62][24] It is configured atrun time.[citation needed] This removes the need for a compilation step or load-time weaving.[citation needed] On the other hand, interception only allows for public method-execution on existing objects at ajoin point.[citation needed]
Compared to theAspectJ framework, Spring AOP is less powerful, but also less complicated.[citation needed] Spring 1.2 includes support to configure AspectJ aspects in the container. Spring 2.0 added more integration with AspectJ; for example, thepointcut language is reused and can be mixed with Spring AOP-based aspects.[citation needed] Further, Spring 2.0 added a Spring Aspects library that uses AspectJ to offer common Spring features such as declarative transaction management[62] and dependency injection via AspectJ compile-time or load-time weaving.[63]SpringSource uses AspectJ AOP in other Spring projects such as Spring Roo and Spring Insight, with Spring Security offering an AspectJ-based aspect library.[citation needed]
Spring AOP has been designed to work with cross-cutting concerns inside the Spring Framework.[4]: 473 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, andJMX.[64]
Since version 2.0 of the framework, Spring provides two approaches to the AOP configuration:
@AspectJ-based annotation style.[66][better source needed]<beansxmlns="http://www.springframework.org/schema/beans"xmlns:mvc="http://www.springframework.org/schema/mvc"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:aop="http://www.springframework.org/schema/aop"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
The Spring team decided not to introduce new AOP-related terminology. Therefore, in the Spring reference documentation and API, terms such asaspect, join point,advice, pointcut, introduction,target object (advised object),AOP proxy, and weaving all have the same meanings[citation needed] as in most other AOP frameworks (particularly AspectJ).
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,iBatis/MyBatis,[32]Hibernate,[32]Java Data Objects (JDO, discontinued since 5.x),[32]Jakarta Persistence API (JPA),[32]Oracle TopLink,Apache OJB, andApache Cayenne, among others.
For all of these supported frameworks, Spring provides these features
All these features become available when usingtemplate classes provided by Spring for each supported framework.[68] Critics have said these template classes are intrusive and offer no advantage over using (for example) the Hibernate API directly.[69][failed verification] 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,[70] and does not support exception translation.[71]
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.[citation needed] The Spring Framework is the only framework available in Java that offers managed data access environments outside of an application server or container.[72][better source needed]
While using Spring for transaction management with Hibernate, the following beans may have to be configured:
Datasource likecom.mchange.v2.c3p0.ComboPooledDataSource ororg.apache.commons.dbcp.BasicDataSource[32]SessionFactory likeorg.springframework.orm.hibernate3.LocalSessionFactoryBean with aDataSource attribute[73][4]: 173 HibernateProperties[4]: 173 likeorg.springframework.beans.factory.config.PropertiesFactoryBeanTransactionManager likeorg.springframework.orm.hibernate3.HibernateTransactionManager with aSessionFactory attribute[73]Other points of configuration include:
Spring's transaction management framework brings an abstraction mechanism to the Java platform.[74] Its abstraction is capable of:
In comparison,Java Transaction API (JTA) only supports nested transactions and global transactions, and requires an application server (and in some cases, deployment of applications in an application server).
The Spring Framework ships aPlatformTransactionManager[76] for a number of transaction management strategies:
JtaTransactionManager[77][4]: 255–257 andUserTransaction[4]: 234 Next to this abstraction mechanism the framework provides two ways of adding transaction management to applications:
TransactionTemplate[78]@Transactional,[62] etc.)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 orEJB. The transactional framework also integrates with messaging[79] andcaching[80] engines.
The Spring Framework features its ownmodel–view–controller (MVC)web application framework,[35] which was not 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 (then) popularJakarta Struts Web framework,[81][failed verification] 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.[82]
Like Struts, Spring MVC is a request-based framework.[4]: 375 The framework definesstrategy interfaces[4]: 144 for all of the responsibilities that 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 theServlet 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 of abstraction for Web-based applications[citation needed]. However, this coupling ensures that the features of the Servlet API remain available to developers while offering a high abstraction framework to ease working with it.
TheDispatcherServlet class is thefront controller[83] of the framework and is responsible for delegating control to the various interfaces during the execution phases of anHTTP request.[84]
The most important interfaces defined by Spring MVC, and their responsibilities, are listed below:[85]
Controller: comes betweenModel andView to manage incoming requests and redirect to proper response.[86]Controller will map the http request to corresponding methods.[87] It acts as a gate that directs the incoming information. It switches between going intoModel orView.HandlerAdapter: responsible for execution of objects that handle incoming requests.[88]HandlerInterceptor: responsible for intercepting incoming requests.[88] Comparable, but not equal to Servlet filters[4]: 509 (use is optional[4]: 511 and not controlled byDispatcherServlet).HandlerMapping: responsible for selecting objects that handle incoming requests (handlers) based on any attribute or condition internal or external to those requests[84]LocaleResolver: responsible for resolving and optionally saving of thelocale of an individual user.[89]MultipartResolver: facilitate working with file uploads by wrapping incoming requests.[90]View: responsible for returning a response to the client. TheView should not contain any business logic and should only present the data encapsulated by theModel.[35] Some requests may go straight toView without going to theModel part; others may go through all three.ViewResolver: responsible for selecting aView based on a logical name for theView[91][92] (use is not strictly required[4]: 511 ).Model: responsible for encapsulating business data.[91] TheModel is exposed to the view by the controller.[4]: 374 (use is not strictly required).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.[4]: 144 Spring MVC ships with implementations of all these interfaces and offers a feature set on top of the Servlet API. However, developers and vendors are free to write other implementations. Spring MVC uses the Javajava.util.Map interface as a data-oriented abstraction for theModel where keys are expected to beString values.[citation needed]
The ease of testing the implementations of these interfaces is one important advantage of the high level of abstraction offered by Spring MVC.[93][4]: 324 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.
When a user clicks a link or submits a form in their web-browser, the request goes to the SpringDispatcherServlet.DispatcherServlet is afront-controller in Spring MVC.[84][94] TheDispatcherServlet is highly customizable and flexible.[94] Specifically, it is capable of handling more types of handlers than any implementations oforg.springframework.web.servlet.mvc.Controller ororg.springframework.stereotype.Controller annotated classes.[94] It consults one or more handler mappings.[84]DispatcherServlet chooses an appropriate controller and forwards the request to it. TheController processes the particular request and generates a result. It is known asModel. This information needs to be formatted in html or any front-end technology likeJakarta Server Pages (also known as JSP)[84][95] orThymeleaf.[95] This is theView of an application.[84] All of the information is in theModel AndView object. When the controller is not coupled to a particular view,DispatcherServlet finds the actualView (such as JSP) with the help ofViewResolver.[84][4]: 390–391
As of Servlet Specification version 3.0, there are a few ways of configuring the DispatcherServlet:[96]
web.xml as shown below:[96]<servlet><servlet-name>MyServlet</servlet-name><servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class></servlet><servlet-mapping><servlet-name>MyServlet</servlet-name><url-pattern>/<url-pattern></servlet-mapping>
web-fragment.xml[96]javax.servlet.ServletContainerInitializer[96] org.springframework.web.WebApplicationInitializer interface.[96]SpringBootServletInitializer class.lm[96]Spring's Remote Access framework is an abstraction for working with various RPC (remote procedure call)-based technologies available on the Java platform both for client connectivity and marshalling objects on servers.[97] 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 control and AOP.
The framework provides fault-recovery (automatic reconnection after connection failure) and some optimizations for client-side use of EJB remotestateless 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 objects on the server side.[100]
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 an alternative open-source implementation (Cluster4Spring) of a remoting subsystem included in the Spring Framework that is intended to support various schemes of remoting (1-1, 1-many, dynamic services discovering).[citation needed]
Spring Boot Extension is Spring'sconvention-over-configuration solution for creatingstand-alone, production-grade[101] Spring-based Applications that you can "just run".[102] It is preconfigured with the Spring team's "opinionated view"[103][104] of the best configuration and use of the Spring platform and third-party libraries so you can get started with minimum fuss. Most Spring Boot applications need very little Spring configuration.[105]
Key Features:
Spring Roo is a community project which provides an alternative, code-generation based approach at using convention-over-configuration to rapidly build applications inJava. It currently supports Spring Framework, Spring Security andSpring Web Flow. Roo differs from otherrapid application development frameworks by focusing on:
Spring Batch is a framework forbatch processing that provides reusable functions that are essential in processing large volumes of records, including:
It provides more advanced technical services and features that enables extremely high-volume[113] and high-performance batch jobs[112] through optimizations and partitioning[112] techniques.
Spring Batch executes a series of jobs; a job consists of many steps and each step consists of a "READ-PROCESS-WRITE" task or single operation task (tasklet). A "single" operation task is also known as a tasklet.[114] It means doing a single task only, like cleaning up the resources before or after a step is started or completed.
The "READ-PROCESS-WRITE" process consists of these steps: "read" data from a resource (comma-separated values (CSV), XML, or database), "process" it, then "write" it to other resources (CSV, XML, or database). For example, a step may read data from a CSV file,[114] process it, and write it into the database. Spring Batch provides many classes to read/write CSV, XML, and database.[115]
The steps can be chained together to run as a job.[114]
Spring Integration is a framework forEnterprise application integration that provides reusable functions essential to messaging orevent-driven architectures.
@ServiceActivator to declare the component that requires this functionality.[121]SimpleMessagingGateway, provides essential support for gateways.SimpleMessagingGateway enables the Spring application to specify the channel that sends requests, and the channel that expects to receive responses. The primary focus ofSimpleMessagingGateway is to deal with payloads, which spares the client from the intricate details of the transmitted and received messages.SimpleMessagingGateway is used along with channels to enable integration with file systems, JMS, e-mail, or any other systems that require payloads and channels.[122]@Splitter annotation to declare the component that requires this functionality.[123]@Aggregator annotation to declare the component that requires this functionality.[123]Spring Integration supports pipe-and-filter based architectures.
An essential rule for dealing with data streams effectively is to never block.[124] The WebSocket is a viable solution to this problem.[124] The WebSocket Protocol is a low-leveltransport protocol that allowsfull-duplex communication channels over aTCP connection. The WebSocket acts as an alternative to HTTP to enable two-way communication between the client and the server. The WebSocket is especially useful for applications that require frequent and fast exchanges of small data chunks, at a high speed and volume.[124]
Spring supports the WebSocket protocol by providing the WebSocket API for the reactive application. The@EnableWebSocket annotation gives Websocket request processing functionality when places in a Spring configuration class. A mandatory interface is theWebSocketConfigurer which grants access to theWebSocketConfigurer. Then, the Websocket URL is mapped to the relevant handlers by implementing the registerWebSocketHandlers(WebSocketHandlerRegistry) method.[125]
Spring WebFlux is a framework following the functional programming paradigm, designed for building reactive Spring applications. This framework uses functional programming and Reactive Streams extensively. A good use case for Spring WebFlux is for applications that require sending and receiving instantaneous information, such as a web application with chatting capabilities.[126]
Although applications using Spring WebFlux technology is usually less readable than their MVC counterparts, they are more resilient, and simpler to extend.[127] Spring WebFlux reduces the need to deal with the complications associated with synchronizing thread access.[127]
Spring WebFlux supportsserver-sent events (SSE), which is a server push technology that allows the client to get automatic updates from a server through an HTTP connection. This communication is unidirectional, and shares many similarities with the publish/subscribe model found in JMS.[124]
The container can be turned into a partially compliantEJB (Enterprise JavaBeans) 3.0 container by means of the Pitchfork project.[citation needed] Some[who?] criticize the Spring Framework for not complying with standards.[128][failed verification] However, SpringSource doesn't see EJB 3 compliance as a major goal, and claims that the Spring Framework and the container allow for more powerful programming models.[129][failed verification]
Aremote code execution vulnerability affecting certain versions of Spring Framework was published in April 2022 underCVE-2022-22965. It was given the nameSpring4Shell in reference to the recentLog4Shell vulnerability, both having similar proofs-of-concept in which attackers could on vulnerable machines, gain shell access[130] or even full control.[131]
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