【導(dǎo)讀】JSP是由SunMicrosystems公司倡導(dǎo)、許多公司參與一起建立的一種。動(dòng)態(tài)網(wǎng)頁(yè)技術(shù)標(biāo)準(zhǔn)。JSP技術(shù)有點(diǎn)類似ASP技術(shù)，它是在傳統(tǒng)的網(wǎng)頁(yè)HTML文件。中插入Java程序段和JSP標(biāo)記，從而形成JSP文件。用JSP開(kāi)發(fā)的Web應(yīng)用是跨平臺(tái)的，即能在Linux下運(yùn)行，也能在其他操作系統(tǒng)上運(yùn)行。JSP技術(shù)使用Java編程語(yǔ)言編寫類XML的tags和scriptlets，來(lái)封裝產(chǎn)生動(dòng)態(tài)網(wǎng)頁(yè)的處理。網(wǎng)頁(yè)還能通過(guò)tags和scriptlets訪問(wèn)存在于服務(wù)端的資源的應(yīng)用邏輯。變得迅速和容易。插入的Java程序段可以操作數(shù)據(jù)庫(kù)、重新定向。JSP的規(guī)范的最后版本是1999年9月推出的，12月又推出了規(guī)范。規(guī)范，規(guī)范的征求意見(jiàn)稿也已出臺(tái)。JSP頁(yè)面由HTML代碼和嵌入其中的Java代碼所組成。這些Java代碼進(jìn)行處理，然后將生成的HTML頁(yè)面返回給客戶端的瀏覽器。JSP的技術(shù)基礎(chǔ)，而且大型的Web應(yīng)用程序的開(kāi)發(fā)需要JavaServlet和JSP配合才能完成。向因特網(wǎng)的所有特點(diǎn)。相比ASP/PHP的局限性是顯而易見(jiàn)的。服務(wù)器，Java顯示了一個(gè)巨大的生命力。覽器后，服務(wù)器端該客戶的session對(duì)象才取消，并且和客戶的會(huì)話對(duì)應(yīng)關(guān)系消失。

　　

【正文】 API to encourage developers to adopt a modelviewcontroller (MVC) architecture. It was originally created by Craig McClanahan and donated to the Apache Foundation in May, 2020. Formerly located under the Apache Jakarta Project and known as Jakarta Struts, it became a top level Apache project in 2020. Design goals and overview In a standard Java EE web application, the client will typically submit information to the server via a web form. The information is then either handed over to a Java Servlet which processes it, interacts with a database and produces an HTMLformatted response, or it is given to a JavaServer Pages (JSP) document which intermingles HTML and Java code to achieve the same result. Both approaches are often considered inadequate for large projects because they mix application logic with presentation and make maintenance difficult. The goal of Struts is to cleanly separate the model (application logic that interacts with a database) from the view (HTML pages presented to the client) and the controller (instance that passes information between view and model). Struts provides the controller (a servlet known as ActionServlet) and facilitates the writing of templates for the view or presentation layer (typically in JSP, but XML/XSLT and Velocity are also supported). The web application programmer is responsible for writing the model code, and for creating a central configuration file which binds together model, view and controller. Requests from the client are sent to the controller in the form of Actions defined in the configuration file。 if the controller receives such a request it calls the corresponding Action class which interacts with the application specific model code. The model code returns an ActionForward, a string telling the controller which output page to send to the client. Information is passed between model and view in the form of special JavaBeans. A powerful custom tag library allows it to read and write the content of these beans from the presentation layer without the need for any embedded Java code. Struts also supports i18n (internationalization), provides facilities for the validation of data submitted by web forms, and includes a template mechanism called Tiles which (for instance) allows the presentation layer to be posed from independent header, footer, and content ponents. Competing MVC frameworks Although Struts is a well documented, mature and popular framework for building front ends to Java applications, it is facing new challenges from newer light weight MVC frameworks such as Spring MVC, Stripes and Tapestry. The new XForms standards and frameworks may also be another option to building plex web Form validations with Struts in the future. The WebWork framework spun off from Apache Struts several years ago, aiming to offer enhancements and refinements while retaining the same general architecture of the original Struts framework. However, it was announced in December 2020 that Struts would remerge with WebWork. WebWork has been adopted as Apache Struts 2, which reached its first full release in February 2020. Sun recently brought out a new addition to the Java platform, called JavaServer Faces (JSF). Aside from the original framework, the Apache Struts project also offers a JSFbased framework called Shale. Other MVC frameworks that are not J2EE based include Ruby on Rails, WebObjects, Django, Catalyst, TurboGears, CakePHP, Symfony (for PHP), Zend, Achievo ATK, and CodeIgniter (for PHP). Struts4php is a version of the Struts framework for the PHP web scripting language. Girders is a port of the Struts framework in C for Microsoft .NET. === 中文 === Struts 是 Apache 軟件基金會(huì)（ ASF）贊助的一個(gè)開(kāi)源項(xiàng)目。它最初是 Jakarta 項(xiàng)目中的一個(gè)子項(xiàng)目，并在 2020 年 3月成為 ASF 的頂級(jí)項(xiàng)目。它通過(guò)采用 Java Servlet/JSP 技術(shù)，實(shí)現(xiàn)了基于 Java EE Web 應(yīng)用的 ModelViewController〔 MVC〕設(shè)計(jì)模式的應(yīng)用框架〔 Web Framework〕，是 MVC 經(jīng)典設(shè)計(jì)模式中的一個(gè)經(jīng)典產(chǎn)品。 MVC 結(jié)構(gòu) 在 Struts 中，已經(jīng)由一個(gè)名為 ActionServlet 的 Servlet 充當(dāng) 控制器 (Controller)的角色，根據(jù)描述模型、視圖、控制器對(duì)應(yīng)關(guān)系的 的配置文件，轉(zhuǎn)發(fā)視圖 (View)的請(qǐng)求，組裝響應(yīng)數(shù)據(jù)模型（ Model）。在 MVC 的 模型（ Model）部分，經(jīng)常劃分為兩個(gè)主要子系統(tǒng)（系統(tǒng)的內(nèi)部數(shù)據(jù)狀態(tài)與改變數(shù)據(jù)狀態(tài)的邏輯動(dòng)作），這兩個(gè)概念子系統(tǒng)分別具體對(duì)應(yīng) Struts 里的 ActionForm 與 Action 兩個(gè)需要繼承實(shí)現(xiàn)超類。在這里， Struts 可以與各種標(biāo)準(zhǔn)的數(shù)據(jù)訪問(wèn)技術(shù)結(jié)合在一起，包括 Enterprise Java Beans（ EJB） , JDBC 與 JNDI。在 Struts 的視圖（ View） 端，除了使用標(biāo)準(zhǔn)的 JavaServer Pages（ JSP）以外，還提供了大量的標(biāo)簽庫(kù)使用，同時(shí)也可以與其他表現(xiàn)層組件技術(shù)（產(chǎn)品）進(jìn)行整合，比如 Velocity Templates， XSLT 等。通過(guò)應(yīng)用 Struts 的框架，最終用戶可以把大部分的關(guān)注點(diǎn)放在自己的業(yè)務(wù)邏輯（ Action）與 映射關(guān)系的配置文件（ ）中。 發(fā)展歷程 在 Java EE 的 Web應(yīng)用發(fā)展的初期，除了使用 Servlet 技術(shù)以外，普遍是在 JavaServer Pages (JSP)的源代碼中，采用 HTML 與 Java 代碼混合的方式進(jìn)行開(kāi)發(fā)。因?yàn)檫@兩種方式不可避免的要把表現(xiàn)與業(yè)務(wù)邏輯代碼混合在一起，都給前期開(kāi)發(fā)與后期維護(hù)帶來(lái)巨大的復(fù)雜度。為了擺脫上述的約束與局限，把業(yè)務(wù)邏輯代碼從表現(xiàn)層中清晰的分離出來(lái)， 2020年，Craig McClanahan 采用了 MVC 的設(shè)計(jì)模式開(kāi)發(fā) Struts。后來(lái)該框架產(chǎn)品一度被認(rèn)為是最廣泛、最流行 JAVA 的 WEB 應(yīng)用框架。 2020 年， WebWork 與 Struts 這兩個(gè)優(yōu)秀的 Java EE Web 框架 (Web Framework〕的團(tuán)體，決定合作共同開(kāi)發(fā)一個(gè)新的，整合了 WebWork 與 Struts 優(yōu)點(diǎn)，并且更加優(yōu)雅、擴(kuò)展性更強(qiáng)的框架，命名為 “Struts 2”，原 Struts 的 版本產(chǎn)品稱為 “Struts 1”。 至此， Struts 項(xiàng)目并行提供與維護(hù)兩個(gè)主要版本的框架產(chǎn)品 ——Struts 1 與 Struts 2。