MVC风格

MVC风格

点击了解很多其它软件体系结构风格

§模型-视图-控制器风格常被简称为MVC风格

§组件：模型、视图、控制器

§连接件：显式调用、隐式调用、其它机制(比如：Http协议)

工作机制：

Model:

§模型的职责

–负责数据存取

–负责业务逻辑实现

–负责数据验证

§模型：模型是应用程序的核心。

它封装内核数据与状态，对模型的改动将扩散到全部视图中。

全部须要从模型获取信息的对象都必须注冊为模型的视图。

§在事件驱动系统，当信息发生改变，模型通知观察者(observers) (一般是视图)，从而引起视图反应。

View:

§视图的职责:

–获取用户输入

–向controller发送处理请求

–接收来自Controller的反馈

–将model的处理结果显示给用户

§一个model可能有多个View

Controller:

§控制器职责:

–接收来自客户的请求

–调用model运行

–调用View显示运行结果

§控制器：控制器是提供给用户进行操作的接口。每一个视图与一个控制器组件相关联。控制器接收用户的输入，一般是鼠标移动、键盘输入等。输入事件翻译成服务请求，送到模型或视图。用户仅仅通过控制器与系统交互。

§两个主要分离:

–模型与界面分离

–控制器与视图分离

§长处:

–将各方面问题分解开来考虑，简化了系统设计，保证了系统的可扩展性。

–改变界面不影响应用程序的功能内核，使得系统易于演化开发，可维护性好。

–同一信息能够有不同的展现方式。

–业务逻辑更易測试

程序：

模型类CarModel封装二手车软件的业务逻辑部分。包含核心数据以及tell()方法（将状态的改变通知视图类）

import java.io.*;

import java.net.URL;

import java.net.URI;

import javax.swing.*;

importjava.util.*;

public classCarModel{

private String[] carNameList;

privateURL imgURL;

privateURL carFileUrl;

privateImageIcon imgIcon;

private String carSelected;

private String bitPrice;

static final String CARFILES ="CarFiles/";

static final String CARIMAGES ="CarImages/";

public CarModel(){

carNameList=new String[200];

}

public void setCarList(String[] cars){

carNameList = cars;

}

public String[] getCarList(){

return  carNameList;

}

public void setSelectedCar(String sCar){

carSelected = sCar;

}

publicString getSelectedCar(){

return carSelected;

}

publicvoid setBitPrice(String bPrice){

bitPrice = "";

bitPrice = bitPrice + bPrice;

}

public String getBitPrice(){

return bitPrice;

}

public void setupImageIcon(){

String iconStr = CARIMAGES + carSelected+".jpg";

imgIcon = createImageIcon(iconStr);

}

public ImageIcon getImageIcon(){

return imgIcon;

}

public void setCarFileURL(){

try{

String fileURLStr = CARFILES + carSelected+ ".html";

URI uri = (new File(fileURLStr)).toURI();

carFileUrl= uri.toURL();

}

catch (IOException e){

e.printStackTrace();

}

}

public URL getCarFileURL(){

return carFileUrl;

}

protected ImageIcon createImageIcon(Stringpath){

imgURL = getClass().getResource(path);

if (imgURL != null) {

return new ImageIcon(imgURL);

} else {

System.err.println("Couldn'tfind file: " + path);

return null;

}

}

public void tell(View view){

view.update();

}

} // End ofclass

视图类CararGUIView和CarBitView为图形界面类，在update()方法中自己主动调用CarModel类的有关信息。并显示在图形界面上。

public interface View{

publicabstract void update();

}

import java.awt.*;

import java.util.*;

import javax.swing.*;

import java.io.*;

import java.net.URL;

import java.awt.event.*;

import com.sun.java.swing.plaf.windows.*;

public classCarGUIView extends JFrame implements View{

private JEditorPane editorPane;

private JScrollPane imagePane;

private JScrollPane textPane;

private JSplitPane splitPane;

private JLabel imgLabel;

private CarModel model;

public CarGUIView(CarModel cmodel){

super("Car information- Observer1");

model = cmodel;

buildUpScrollGUI();

}

private void buildUpScrollGUI(){

imgLabel = new JLabel();

imgLabel.setBackground(Color.green);

imgLabel.setMinimumSize(new Dimension(250, 200));

editorPane = new JEditorPane();

editorPane.setEditable(false);

imagePane = new JScrollPane(imgLabel);

imagePane.getViewport().setBackground(Color.green);

textPane = new JScrollPane(editorPane);

textPane.setMinimumSize(new Dimension(250, 200));

splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT);

splitPane.setLeftComponent(imagePane);

splitPane.setRightComponent(textPane);

Dimension minimumSize = new Dimension(130, 100);

imagePane.setMinimumSize(minimumSize);

textPane.setMinimumSize(new Dimension(100, 100));

splitPane.setDividerLocation(160);

splitPane.setPreferredSize(new Dimension(500, 300));

Container contentPane = getContentPane();

contentPane.add(splitPane);

setSize(400, 150);

setVisible(true);

}

public void update(){

try{

URL url = model.getCarFileURL();

editorPane.setPage(url);

System.out.println("We have beencalled.");

}

catch (IOException e){

e.printStackTrace();

}

ImageIcon imIcon = model.getImageIcon();

imgLabel.setIcon(imIcon);

imgLabel.validate();

}

}

import java.awt.*;

importjavax.swing.*;

public classCarBitView extends JFrame implements View{

private JPanel showPanel;

private JLabel bitOfferedLabel;

private JTextArea bitText;

private CarModel model;

//public CarBitView(CarModel cmodel) throwsException{

public CarBitView(CarModel cmodel) {

super("Car Bit Info View- Observer2");

model = cmodel;

bitOfferedLabel = newJLabel("Latest bit offered:");

bitText = new JTextArea(4, 20);

bitText.setFont(newFont("Serif", Font.PLAIN, 14));

bitText.setLineWrap(true);

bitText.setWrapStyleWord(true);

Container contentPane =getContentPane();

contentPane.add(bitOfferedLabel,BorderLayout.NORTH);

contentPane.add(bitText,BorderLayout.CENTER);

setSize(400, 150);

setVisible(true);

}

public void update(){

System.out.println("Car bit hasbeen called.");

String sCar= model.getSelectedCar();

String pr = model.getBitPrice();

bitText.append("\n Bit price for"+ sCar + "="+ pr);

}

}// end ofclass

控制器Controller负责依据CarAuctionGUI对象输入的客户选择信息更新CarModel的数据。

importjava.awt.event.*;

importjavax.swing.*;

importjava.net.URL;

classController implements ActionListener{

private CarAuctionGUI objCarGui;

private CarModel cm;

private CarGUIView civ;

private CarBitView cb;

private String carPrice;

private String[] carList;

public Controller(CarAuctionGUIobjCarGui,CarModel cm,

CarGUIView civ,CarBitViewcb){

this.objCarGui = objCarGui;

this.cm=cm;

this.civ=civ;

this.cb=cb;

carList = objCarGui.getCarList();

cm.setCarList(carList);

}

public void actionPerformed(ActionEvent e){

String searchResult = null;

if(e.getActionCommand().equals(CarAuctionGUI.EXIT)){

System.exit(1);

}

if(e.getActionCommand().equals(CarAuctionGUI.SEARCH)){

String selectedCar =objCarGui.getSelectedCar();

cm.setSelectedCar(selectedCar);

cm.setCarFileURL();

cm.setupImageIcon();

cm.tell(civ);

}

if(e.getActionCommand().equals(CarAuctionGUI.BIT)){

carPrice = objCarGui.getBitPrice();

cm.setBitPrice(carPrice);

cm.tell(cb);

}

}

} // End ofclass Controller

importjava.awt.*;

import java.util.*;

import javax.swing.*;

import java.io.*;

import java.net.URL;

import java.awt.event.*;

import com.sun.java.swing.plaf.windows.*;

public classCarAuctionGUI extends JPanel {

private JTextField bitInputText;

private JLabel lblCarModel;

private JPanel buttonPanel;

private String[] carList;

private JComboBox cmbCarList;

private static CarModel cm;

private static CarGUIView civ;

private static CarBitView cb;

public static final String SEARCH ="Search";

public static final String BIT ="Bit";

public static final String EXIT ="Exit";

public CarAuctionGUI(){

super(new GridLayout(1,0));

setUpGUI();

}

private void setUpGUI(){

cmbCarList = new JComboBox();

String[] cl = getCarList();

setUpCarList(cl);

lblCarModel = new JLabel("Cars on auction:");

//Create the open button

JButton srchButton = new JButton(SEARCH);

srchButton.setMnemonic(KeyEvent.VK_S);

JButton exitButton = new JButton(EXIT);

exitButton.setMnemonic(KeyEvent.VK_X);

JButton bitButton = new JButton(BIT);

bitButton.setMnemonic(KeyEvent.VK_X);

bitInputText = new JTextField("Offeryour bit price",12);

buttonPanel = new JPanel();

//****************************************************

GridBagLayout gridbag = newGridBagLayout();

buttonPanel.setLayout(gridbag);

GridBagConstraints gbc = new GridBagConstraints();

buttonPanel.add(lblCarModel);

buttonPanel.add(cmbCarList);

buttonPanel.add(srchButton);

buttonPanel.add(bitButton);

buttonPanel.add(exitButton);

buttonPanel.add(bitInputText);

gbc.insets.top = 5;

gbc.insets.bottom = 5;

gbc.insets.left = 5;

gbc.insets.right = 5;

gbc.anchor = GridBagConstraints.EAST;

gbc.gridx = 0;

gbc.gridy = 0;

gridbag.setConstraints(lblCarModel, gbc);

gbc.anchor = GridBagConstraints.WEST;

gbc.gridx = 1;

gbc.gridy = 0;

gridbag.setConstraints(cmbCarList, gbc);

gbc.anchor = GridBagConstraints.EAST;

gbc.insets.left = 2;

gbc.insets.right = 2;

gbc.insets.top = 25;

gbc.anchor = GridBagConstraints.EAST;

gbc.gridx = 0;

gbc.gridy = 3;

gridbag.setConstraints(srchButton, gbc);

gbc.anchor = GridBagConstraints.WEST;

gbc.gridx = 1;

gbc.gridy = 3;

gridbag.setConstraints(exitButton, gbc);

gbc.gridx = 0;

gbc.gridy = 4;

gridbag.setConstraints(bitButton, gbc);

gbc.gridx = 1;

gbc.gridy = 4;

gridbag.setConstraints(bitInputText,gbc);

Controller objButtonHandler = newController(this,cm,civ,cb);

srchButton.addActionListener(objButtonHandler);

exitButton.addActionListener(objButtonHandler);

bitButton.addActionListener(objButtonHandler);

add(buttonPanel);

setSize(new Dimension(800, 450));

setVisible(true);

}

public String getSelectedCar() {

return (String) cmbCarList.getSelectedItem();

}

public String getBitPrice(){

return       bitInputText.getText();

}

// get the names of all the .html filesin a directory

public String[] getCarList(){

File f = new File("CarFiles");

String [] fileNames = f.list();

for(int i=0; i<fileNames.length; i++ ){

int len = fileNames[i].length();

fileNames[i]=fileNames[i].substring(0,len-5);

}

return fileNames;

}

public void setUpCarList(String[]carList){

for(int k=0; k<carList.length; k++) {

cmbCarList.addItem(carList[k]);

}

}

private static void createAndShowGUI() {

JFrame.setDefaultLookAndFeelDecorated(true);

JFrame frame = new JFrame("MVCpattern demo");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

CarAuctionGUI newContentPane = newCarAuctionGUI();

newContentPane.setOpaque(true);

frame.setContentPane(newContentPane);

//Display the window.

frame.pack();

frame.setVisible(true);

}

static public void main(String argv[]) {

javax.swing.SwingUtilities.invokeLater(newRunnable() {

public void run() {

cm = new CarModel();

civ= new CarGUIView(cm);

cb = new CarBitView(cm);

createAndShowGUI();

}

});

}

}