中英文对照外文翻译文献
(文档含英文原文和中文翻译)
原文：
Struts——an open-source MVC implementation
This article introduces Struts, a Model-View-Controller implementation that uses servlets and JavaServer Pages (JSP) technology. Struts can help you control change in your Web project and promote specialization. Even if you never implement a system with Struts, you may get some ideas for your future servlets and JSP page implementation.
毕业设计外文资料翻译
Model-View-Controller (MVC)
JSP tags solved only part of our problem. We still have issues with validation, flow control, and updating the state of the application. This is where MVC comes to the rescue. MVC helps resolve some of the issues with the single module approach by dividing the problem into three categories:
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Model
The model contains the core of the application's functionality. The model encapsulates the state of the application. Sometimes the only functionality it contains is state. It knows nothing about the view or controller.
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View
The view provides the presentation of the model. It is the
look of the application. The view can access the model getters,
but it has no knowledge of the setters. In addition, it knows nothing about the controller. The view should be notified when changes to the model occur.
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Controller
The controller reacts to the user input. It creates and sets the model.
MVC Model 2
毕业设计外文资料翻译
The Web brought some unique challenges to software developers, most notably the stateless connection between the client and the server. This stateless behavior made it difficult for the model to notify the view of changes. On the Web, the browser has to re-query the server to discover modification to the state of the application. Another noticeable change is that the view uses different technology for implementation than the model or controller. Of course, we could use Java (or PERL, C/C++ or what ever) code to generate HTML. There are several disadvantages to that approach:
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Java programmers should develop services, not HTML. Changes to layout would require changes to code.
Customers of the service should be able to create pages to meet their specific needs.
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The page designer isn't able to have direct involvement in page development.
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HTML embedded into code is ugly.
For the Web, the classical form of MVC needed to change. Figure 4 displays the Web adaptation of MVC, also commonly known as MVC Model 2 or MVC 2. Struts details
毕业设计外文资料翻译
The ActionServlet class
Do you remember the days of function mappings? You would map some input event to a pointer to a function. If you where slick, you would place the configuration information into a file and load the file at run time. Function pointer arrays were the good old days of structured programming in C.
Life is better now that we have Java technology, XML, J2EE, and all that. The Struts Controller is a servlet that maps events (an event generally being an HTTP post) to classes. And guess what -- the Controller uses a configuration file so you don_t have to hard-code the values. Life changes, but stays the same. ActionServlet is the Command part of the MVC implementation and is the core of the Framework. ActionServlet (Command) creates and uses Action, an ActionForm, and ActionForward. As mentioned earlier, the struts-config.xml file configures the Command. During the creation of the Web project, Action and ActionForm are extended to solve the specific problem space. The file struts-config.xml instructs ActionServlet on how to use the extended classes. There are several advantages to this approach:
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The entire logical flow of the application is in a hierarchical text file. This makes it easier to view and understand, especially with large applications.
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