经典软件体系结构风格（三）

系统管理员 2022-06-16 07:40 189阅读 0赞

MVC 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、其他机制(例如：Http协议)

\#工作机制：

Model:

\--模型的职责

1.负责数据存取

2.负责业务逻辑实现

3.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，对模型的修改将扩散到所有视图中。所有需要从模型获取信息的对象都必须注册为模型的视图。

在事件驱动系统，当信息发生改变，模型通知观察者(observers) (通常是视图)，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执行

–调用View显示执行结果

控制器：控制器是提供给用户进行操作的接口。每个视图与一个控制器组件相关联。控制器接收用户的输入，通常是鼠标移动、键盘输入等。输入事件翻译成服务请求，送到模型或视图。用户只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

\#优点:

–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。

–同一信息可以有不同的展现方式。

–业务逻辑更易[测试][Link 1]

\# 案例

![Center][]

代码：

CarModel.java(模型层)

package com.medel;
    import java.io.*;
    import java.net.URL;
    import java.net.URI;
    import javax.swing.*;
    
    import com.view.View;
    
    import java.util.*;
    
    public class CarModel{
        private String[] carNameList;
        private URL imgURL;
        private URL carFileUrl;
        private ImageIcon 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;
      	}
      	public String getSelectedCar(){
    	     return carSelected;
      	}
      	public void 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(String path){
           imgURL = getClass().getResource(path);
           if (imgURL != null) {
               return new ImageIcon(imgURL);
           } else {
               System.err.println("Couldn't find file: " + path);
               return null;
           }
       }
       public void tell(View view ){
    	   view.update();
       }
    }

视图层：

View.java

package com.view;
    
    public interface View {
      public abstract void update();
    }

CarBitView.java

package com.view;
    import java.awt.*;
    import javax.swing.*;
    import com.medel.CarModel;
    public class CarBitView extends JFrame implements View{
        private JPanel showPanel;
        private JLabel bitOfferedLabel;
        private JTextArea bitText;
        private CarModel model;
        
    	public CarBitView(CarModel cmodel) {
           super("Car Bit Info View- Observer 2");
           model = cmodel;
    
           bitOfferedLabel = new JLabel("Latest bit offered:");
           bitText = new JTextArea(4, 20);
           bitText.setFont(new Font("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 has been called.");
           String sCar= model.getSelectedCar();
           String pr = model.getBitPrice();
           bitText.append("\n Bit price for "+ sCar + "="+ pr);
         }
    }

CarGUIView.java

package com.view;
    import java.awt.*;
    import javax.swing.*;
    import java.io.*;
    import java.net.URL;
    import com.medel.CarModel;
    public class CarGUIView 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("窗口1--车的信息");
    	  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 been called.");
    	   }
    	   catch (IOException e){
    	      e.printStackTrace();
           }
           ImageIcon imIcon = model.getImageIcon();
           imgLabel.setIcon(imIcon);
    	   imgLabel.validate();
        }
    }

控制层：

Controller.java

package com.control;
    import java.awt.event.*;
    import javax.swing.*;
    
    import com.medel.CarModel;
    import com.view.CarBitView;
    import com.view.CarGUIView;
    
    import java.net.URL;
    public class Controller implements ActionListener{
       private CarAuctionGUI objCarGui;
       private CarModel cm;
       private CarGUIView civ;
       private CarBitView cb;
       private String carPrice;
       private String[] carList;
    
       public Controller(CarAuctionGUI objCarGui,CarModel cm,
                         CarGUIView civ,CarBitView cb){
          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);	//civ.update();
          }
          if (e.getActionCommand().equals(CarAuctionGUI.BIT)){
    	     carPrice = objCarGui.getBitPrice();
    		 cm.setBitPrice(carPrice);
             cm.tell(cb);		//cb.update();
    	  }
       }
    }

CarAuctionGUI.java

package com.control;
    import java.awt.*;
    import javax.swing.*;
    import java.io.*;
    import java.awt.event.*;
    import com.medel.CarModel;
    import com.view.CarBitView;
    import com.view.CarGUIView;
    public class CarAuctionGUI 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 = "寻找";
       public static final String BIT = "确定";
       public static final String EXIT = "退出";
    
       public CarAuctionGUI(){
       	   super(new GridLayout(1,0));
    	   setUpGUI();
       }
       private void setUpGUI(){
          cmbCarList = new JComboBox();
          String[] cl = getCarList();
          setUpCarList(cl);
          lblCarModel = new JLabel("二手车种类及年份:");
    
          //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("请输入你想要的价格：",12);
          buttonPanel = new JPanel();
    
          //****************************************************
          GridBagLayout gridbag = new GridBagLayout();
          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 = new Controller(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 files in 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("MVC pattern demo");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
         CarAuctionGUI newContentPane = new CarAuctionGUI();
         newContentPane.setOpaque(true);
         frame.setContentPane(newContentPane);
    
         //Display the window.
         frame.pack();
         frame.setVisible(true);
      }
    
      static public void main(String argv[]) {
    	 javax.swing.SwingUtilities.invokeLater(new Runnable() {
         public void run() {
    	    cm = new CarModel();
    	    civ= new CarGUIView(cm);
    	    cb = new CarBitView(cm);
            createAndShowGUI();
    	 }
          });
      }
    }

[Link 1]: http://lib.csdn.net/base/softwaretest
[Center]: /images/20220616/205f3217152e4e0cbd3a21d21202ca5b.png