摘要
MVC(Model/View/Controller)的設(shè)計(jì)模式出現(xiàn)在在Smalltalk-80,并在軟件的設(shè)計(jì)中廣泛應(yīng)用。本文介紹一種基于MVC框架的的新網(wǎng)絡(luò)應(yīng)用程序。這種框架把實(shí)施邏輯與表現(xiàn)形式獨(dú)立開來。它也提高了系統(tǒng)的可維護(hù)性,可擴(kuò)展性以及使用模塊數(shù)據(jù)庫備案、模板數(shù)據(jù)庫,通訊對象和緩沖隊(duì)列的性能。
關(guān)鍵詞:MVC、設(shè)計(jì)模式、網(wǎng)絡(luò)應(yīng)用程序

1.簡介
網(wǎng)絡(luò)應(yīng)用系統(tǒng)是一個(gè)基于B(rowser)/ S(erver)模型應(yīng)用系統(tǒng)。它利用多種動(dòng)態(tài)網(wǎng)頁開發(fā)技術(shù)。目前,軟件設(shè)計(jì)的主題之一是網(wǎng)絡(luò)應(yīng)用開發(fā)模式和工具的。它們直接影響系統(tǒng)的幾個(gè)關(guān)鍵因素,比如可維護(hù)性、可擴(kuò)展性、穩(wěn)定性和安全性。本文中，基于MVC[1]的網(wǎng)絡(luò)應(yīng)用程序的設(shè)計(jì)模式是為解決這兩類因素——擴(kuò)展性和可維護(hù)性這些不易處理的問題。把MVC設(shè)計(jì)模式引入網(wǎng)絡(luò)應(yīng)用程序開發(fā)，執(zhí)行邏輯可以獨(dú)立于系統(tǒng)的表現(xiàn)形式。
MVC由三種對象組成。1)模型:是應(yīng)用對象，2)視圖:是它的屏幕的顯示,3)控制器:
定義用戶界面并對輸入的信息做出響應(yīng)。在出現(xiàn)MVC之前,用戶界面的設(shè)計(jì)傾向于把這些東西做在一起。然而,MVC獨(dú)立了它們，增加系統(tǒng)的靈活性和可重用性。MVC把視圖和模型獨(dú)立開來,在它們之間建立了“subscribe/notify”協(xié)議。一個(gè)視圖必須確保其正確反映模型的狀態(tài)。每當(dāng)模型的數(shù)據(jù)發(fā)生改變,視圖會(huì)得到相應(yīng)的通知。作為回應(yīng),每個(gè)視圖都會(huì)有更新自身的機(jī)會(huì)。這個(gè)方法可以讓你附上一個(gè)模型的多個(gè)視圖以便提供不同的報(bào)告。你也可以不改變原模型同時(shí)創(chuàng)建新的視圖。

2.背景和存在的問題
雖然MVC的設(shè)計(jì)模式已經(jīng)在smalltalk-80中提出了,并廣泛應(yīng)用于軟件設(shè)計(jì),介紹它到網(wǎng)頁應(yīng)用程序開發(fā)卻仍很困難的。主要由于以下兩個(gè)因素:1)首先,很難獨(dú)立
來自HTML的編程語言。早期的CGI程序使用字符串輸出創(chuàng)造了HTML內(nèi)容。默認(rèn)的,將HTML文本分成幾份,然后把他們嵌入到CGI程序中。腳本語言出現(xiàn)后,變成了腳本語言編寫的程序嵌入到HTML文本中。然而,這兩種方法有一個(gè)共同的不足,使他們不能完


Abstract
The MVC (Model/View/Controller) design pattern was developed in Smalltalk-80 and widely used in software design. This paper introduces a novel Web application frame based on MVC. This frame separates the transaction logic from the presentation format. It also improves the system maintainability, scalability and performance by using the module database, template database, messaging object and buffer queue.
Key words: MVC, Design Pattern, Web Application

1. Introduction
Web application system is a transaction system based on B (rowser)/S(erver) model. It exploits many kinds of dynamic Web developing technologies. At present, Web application developing patterns and tools are one of the topics of the software design. They directly influence several key factors such as maintainability, scalability, stability and the security. In this paper, the purpose of MVC[1]-based Web application design pattern is to resolve the two factors – maintainability and scalability, which are the stubborn problems in the Web application development. By introducing the MVC design pattern into the Web application development, the implementation of system transaction logic can be separated from the system presentation.
MVC consists of three kinds of objects. 1) the Model: is the application object, 2) the View: is its screen presentation, 3) the Controller: defines the way the user interface reacts to user input. Before MVC, user interface designs tended to lump these objects together. However, MVC decouples them to increase the flexibility and reuse. MVC decouples views and models by establishing a “subscribe/notify” protocol between them. A view must ensure that its appearance reflects the state of the model correctly. Whenever the model’s data changes, the model notifies views that depend on it. In response, each view gets an opportunity to update itself. This approach lets you attach multiple views to a model to provide different presentations. You can also create new views for a model without rewriting it.

2. Background and Problems
Even though the MVC design pattern was already put forward in smalltalk-80 and widely used in software design, it is difficult to introduce it into the Web application development. It was mainly due to the following two factors: 1) First, it was difficult to separate the programming language from HTML. Early CGI programs created the HTML content by using character string output. In nature, it divided the HTML content into several portions, and then inserted them into the CGI programs. After the appearance of Script languages, the way changed to insert the programs written by script languages into HTML content. However, these two ways had a common deficiency that they could not separate the programs from the HTML content absolutely. Therefore, it is very difficult to implement the MVC detached three-layer pattern based on these two ways. 2) Second, functions of the script languages are less weak. They lack some necessary technologies to support the MVC design pattern, such as message mechanism and event response