mvc 架構(gòu)

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posted on 2007-11-05 20:58 e全閱讀(316) 評論(0) 編輯收藏

一般來說，可以把系統(tǒng)粗略的分為三個層次，視圖層，簡稱為View，它負責數(shù)據(jù)的輸出和輸入；業(yè)務(wù)層，簡稱為Model，它代表程序的實際業(yè)務(wù)；控制層，簡稱為Controller，處理界面的相應并調(diào)用業(yè)務(wù)層進行處理，有時把View和Controller兩層合稱為UI層。

在程序發(fā)展的歷史上，MVC模式進過了多次演化，MVC1和MVC2是兩種比較典型的模式，它們的區(qū)別主要在于View和Model的聯(lián)系方式上。

（1 ） MVC1 模式

這種模式主要用于桌面程序,使用觀察者模式實現(xiàn),具體來說就是讓View充當觀察者來觀察Model的變化,而用戶交互控制的地方用匿名類的方式統(tǒng)一放在controller中.

View接受用戶輸入,并將交互數(shù)據(jù)傳遞到Controller.

Controller統(tǒng)一進行處理命令,交由Model處理具體的業(yè)務(wù).

進過處理Model更新后,通知View進行更新.

這種模式在舊的桌面應用程序使用較多，但是它的Model必須繼承Observable類，View必須實現(xiàn)Observer接口，人為加大了繼承體系的復雜度；而且Model通知View的方式使View必須了解Model的結(jié)構(gòu)，無謂的加大了兩個類的耦合程度。這些缺點使這種模式逐漸淡出了程序舞臺。

代碼如下:
Control類:

package ?com.sitinspring;

import ?java.awt.event.ActionEvent;

import ?java.awt.event.ActionListener;

import ?java.awt.event.WindowAdapter;

import ?java.awt.event.WindowEvent;

/**

?*?控制類

?*?

?*? @author ?sitinspring(junglesong@gmail.com)

?*?

?*?@date?2007-11-5

? */

public ? class ?Mvc1Ctrl? {

???? private ?Mvc1View?view;

???? private ?Mvc1Model?model;

???? public ?Mvc1Ctrl()? {

????????view? = ? new ?Mvc1View();

????????model? = ? new ?Mvc1Model();

????????model.addObserver(view);

????????handleEvents();

????}

???? // ?處理事件響應

???? private ? void ?handleEvents()? {

????????addCloseLintener();

????????addButtonListener();

????????addButtonListener2();

????}

???? // ?窗體關(guān)閉事件相應

???? private ? void ?addCloseLintener()? {

????????view.addWindowListener( new ?WindowAdapter()? {

???????????? public ? void ?windowClosing(WindowEvent?e)? {

????????????????System.out.println( " Exit?MVC1 " );

????????????????System.exit( 0 );

????????????}

????????} );

????}

???? private ? void ?addButtonListener()? {

????????view.getButton().addActionListener( new ?ActionListener()? {

???????????? public ? void ?actionPerformed(ActionEvent?e)? {

????????????????model.showText();

????????????}

????????} );

????}

????

???? private ? void ?addButtonListener2()? {

????????view.getButton2().addActionListener( new ?ActionListener()? {

???????????? public ? void ?actionPerformed(ActionEvent?e)? {

????????????????model.showText2();

????????????}

????????} );

????}

}

視圖類(View):

package ?com.sitinspring;

import ?java.awt.Dimension;

import ?java.awt.GridLayout;

import ?java.awt.Toolkit;

import ?java.util.Observable;

import ?java.util.Observer;

import ?javax.swing.JButton;

import ?javax.swing.JFrame;

import ?javax.swing.JLabel;

/**

?*?視圖類(View)

?*?

?*? @author ?sitinspring(junglesong@gmail.com)

?*?

?*?@date?2007-11-5

? */

public ? class ?Mvc1View? extends ?JFrame? implements ?Observer? {

???? private ? static ? final ? long ?serialVersionUID? = ? 621145935910133202L ;

???? private ?JButton?button;

???? private ?JLabel?label;

???? private ?JButton?button2;

???? private ?JLabel?label2;

???? public ?Mvc1View()? {

????????locateView( 300 ,? 200 );

???????? this .setTitle( " MVC1?Program " );

????????setupComponents();

???????? this .setVisible( true );

????}

???? // ?當模塊更新時,此函數(shù)會被調(diào)用

???? public ? void ?update(Observable?o,?Object?arg)? {

????????Mvc1Model?model? = ?(Mvc1Model)?o;

???????? if ?(model.getUpdateState().equals(Mvc1UpdateState.UpdateLabel))? {

????????????label.setText(model.getResponseText());

????????} ? else ? if ?(model.getUpdateState().equals(Mvc1UpdateState.UpdateLabel2))? {

????????????label2.setText(model.getResponseText());

????????}

????}

???? // ?定位程序在屏幕正中并設(shè)置程序大小

???? private ? void ?locateView( int ?width,? int ?height)? {

????????Dimension?screenSize? = ?Toolkit.getDefaultToolkit().getScreenSize();

???????? this .setSize(width,?height);

???????? this .setLocation(screenSize.width? / ? 2 ? - ?width? / ? 2 ,?screenSize.height

???????????????? / ? 2 ? - ?height? / ? 2 );

????}

???? // ?初始化內(nèi)部組件

???? private ? void ?setupComponents()? {

????????button? = ? new ?JButton( " 點擊響應事件1 " );

????????label? = ? new ?JLabel( " ??等待事件響應1 " );

????????button2? = ? new ?JButton( " 點擊響應事件2 " );

????????label2? = ? new ?JLabel( " ??等待事件響應2 " );

????????setLayout( new ?GridLayout( 2 ,? 2 ));

????????add(button);

????????add(label);

????????add(button2);

????????add(label2);

????}

???? public ?JButton?getButton()? {

???????? return ?button;

????}

???? public ?JButton?getButton2()? {

???????? return ?button2;

????}

}

模塊類:

package ?com.sitinspring;

import ?java.util.Observable;

/**

?*?模塊類

?*? @author ?sitinspring(junglesong@gmail.com)

?*?@date?2007-11-5

? */

public ? class ?Mvc1Model? extends ?Observable {

???? private ?String?responseText;

???? private ?String?updateState;

????

???? // ?用于通知View更新,此函數(shù)被調(diào)用后View的update函數(shù)會被調(diào)用

???? private ? void ?notifyView() {

????????setChanged();?????????

????????notifyObservers();

????}

????

???? public ? void ?showText() {

????????updateState = Mvc1UpdateState.UpdateLabel;

????????responseText = " ??事件1響應完畢 " ;

????????notifyView();

????}

????

???? public ? void ?showText2() {

????????updateState = Mvc1UpdateState.UpdateLabel2;

????????responseText = " ??事件2響應完畢 " ;

????????notifyView();

????}

???? public ?String?getResponseText()? {

???????? return ?responseText;

????}

???? public ?String?getUpdateState()? {

???????? return ?updateState;

????}

}

更新狀態(tài)輔助類:

package ?com.sitinspring;

public ? class ?Mvc1UpdateState {

???? public ? static ? final ?String?UpdateLabel = " updateLabel " ;

???? public ? static ? final ?String?UpdateLabel2 = " updateLabel2 " ;

}

MVC1示例代碼下載:
http://m.tkk7.com/Files/sitinspring/MVC1.rar

（2）MVC2模式

這種模式首見于網(wǎng)絡(luò)程序，起初因為Model無法通知到Web程序的界面而發(fā)明，這種模式采用Controller做中介者，一方面取得View的輸入，然后交由Model層處理，之后再把返回的數(shù)據(jù)傳遞到View。

View接受用戶輸入,并傳遞到Controller.

Controller統(tǒng)一進行處理命令,交由Model處理具體的業(yè)務(wù).

進過處理Model更新后,Controller會選一個View并把Model內(nèi)容傳遞(request,session)給它(forward).

然后View進行顯示.

這種模式相對 MVC 優(yōu)勢很明顯，首先 Model 和 View 無需繼承甚么東西，其次 Model 和 View 無需了解對方的存在，只需準備相應的接口而已；缺點是 Controller 層變得相對復雜了。

代碼如下:
控制類:

package ?com.sitinspring;

import ?java.awt.event.ActionEvent;

import ?java.awt.event.ActionListener;

import ?java.awt.event.WindowAdapter;

import ?java.awt.event.WindowEvent;

/**

?*?控制類

?*?

?*? @author ?sitinspring(junglesong@gmail.com)

?*?

?*?@date?2007-11-5

? */

public ? class ?Mvc2Ctrl? {

???? private ?Mvc2View?view;

???? private ?Mvc2Model?model;

???? public ?Mvc2Ctrl()? {

????????view? = ? new ?Mvc2View();

????????model? = ? new ?Mvc2Model();

????????handleEvents();

????}

???? // ?處理事件響應

???? private ? void ?handleEvents()? {

????????addCloseLintener();

????????addButtonListener();

????????addButtonListener2();

????}

???? // ?窗體關(guān)閉事件相應

???? private ? void ?addCloseLintener()? {

????????view.addWindowListener( new ?WindowAdapter()? {

???????????? public ? void ?windowClosing(WindowEvent?e)? {

????????????????System.out.println( " Exit?MVC2 " );

????????????????System.exit( 0 );

????????????}

????????} );

????}

???? private ? void ?addButtonListener()? {

????????view.getButton().addActionListener( new ?ActionListener()? {

???????????? public ? void ?actionPerformed(ActionEvent?e)? {

????????????????view.getLabel().setText(model.getText());

????????????}

????????} );

????}

????

???? private ? void ?addButtonListener2()? {

????????view.getButton2().addActionListener( new ?ActionListener()? {

???????????? public ? void ?actionPerformed(ActionEvent?e)? {

????????????????view.getLabel2().setText(model.getText2());

????????????}

????????} );

????}

}

視圖類:

package?com.sitinspring;

import?java.awt.Dimension;

import?java.awt.GridLayout;

import?java.awt.Toolkit;

import?javax.swing.JButton;

import?javax.swing.JFrame;

import?javax.swing.JLabel;

/**

?*?視圖類(View)

?*?

?*?@author?sitinspring(junglesong@gmail.com)

?*?

?*?@date?2007-11-5

?*/

public?class?Mvc2View?extends?JFrame?{

????private?static?final?long?serialVersionUID?=?621145935910133202L;

????private?JButton?button;

????private?JLabel?label;

????private?JButton?button2;

????private?JLabel?label2;

????public?Mvc2View()?{

????????locateView(300,?200);

????????this.setTitle("MVC2?Program");

????????setupComponents();

????????this.setVisible(true);

????}

????//?定位程序在屏幕正中并設(shè)置程序大小

????private?void?locateView(int?width,?int?height)?{

????????Dimension?screenSize?=?Toolkit.getDefaultToolkit().getScreenSize();

????????this.setSize(width,?height);

????????this.setLocation(screenSize.width?/?2?-?width?/?2,?screenSize.height

????????????????/?2?-?height?/?2);

????}

????//?初始化內(nèi)部組件

????private?void?setupComponents()?{

????????button?=?new?JButton("點擊響應事件1");

????????label?=?new?JLabel("??等待事件響應1");

????????button2?=?new?JButton("點擊響應事件2");

????????label2?=?new?JLabel("??等待事件響應2");

????????setLayout(new?GridLayout(2,?2));

????????add(button);

????????add(label);

????????add(button2);

????????add(label2);

????}

????public?JButton?getButton()?{

????????return?button;

????}

????public?JButton?getButton2()?{

????????return?button2;

????}

????public?JLabel?getLabel()?{

????????return?label;

????}

????public?JLabel?getLabel2()?{

????????return?label2;

????}

}

模塊類:

package?com.sitinspring;

/**

?*?模塊類

?*?@author?sitinspring(junglesong@gmail.com)

?*?@date?2007-11-5

?*/

public?class?Mvc2Model{

????public?String?getText(){

????????return?"??事件1響應完畢";

????}

????

????public?String?getText2(){

????????return?"??事件2響應完畢";

????}

}

MVC2示例代碼下載:
http://m.tkk7.com/Files/sitinspring/MVC2.rar


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