我试图找出创建/使用MVC模式模型的最佳方法。 我有一个列表(database
)Person
s和一个View
它代表某些Person
的部分数据。Java Swing MVC - 实现的最佳实践模型
现在的问题是: 如果我有一个大型数据库,每个人都有大量数据,并且我有一个视图面板只代表一个人的一小部分数据,我应该创建一个模型来仅保存可呈现的数据为此,还是应该直接使用Database
作为模型?
我将有不同的意见,这将代表同一个数据库的不同数据。 database
应该是所有视图的模型还是我需要为每个视图面板创建小模型?
这里的一个小例子1个图面板和database
直接作为模型用于所有视图面板:
Main.java
import java.awt.EventQueue;
import javax.swing.JFrame;
public class Main {
private JFrame frame;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
new Main();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public Main() {
initialize();
}
private void initialize() {
Database.getInstance(); // model ?
View view = new View(); // view
Controller controller = new Controller(); // controller
Database.getInstance().addObserver(view);
view.addController(controller);
frame = new JFrame();
frame.add(view.createView());
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
}
Person.java
public class Person {
private String name;
private int age;
private String sex;
public Person(String name, int age, String sex) {
this.name = name;
this.age = age;
this.sex = sex;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
public String getSex() {
return sex;
}
public void setName(String name) {
this.name = name;
}
public void setAge(int age) {
this.age = age;
}
public void setSex(String sex) {
this.sex = sex;
}
}
Database.java(模型)
import java.util.ArrayList;
import java.util.List;
import java.util.Observable;
public class Database extends Observable {
private static Database instance = null;
private List<Person> database = new ArrayList<Person>();
private Database() {
this.database = createDataBase();
}
public static Database getInstance() {
if (instance != null)
return instance;
else
return instance = new Database();
}
private List<Person> createDataBase() {
List<Person> database = new ArrayList<Person>();
database.add(new Person("A", 25, "male"));
return database;
}
public List<Person> getDatabase() {
return database;
}
public void changeData(String name, int age, String sex) {
database.get(0).setName(name);
database.get(0).setAge(age);
database.get(0).setSex(sex);
setChanged();
notifyObservers();
}
}
View.java
import java.awt.BorderLayout;
import java.util.Observable;
import java.util.Observer;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class View implements Observer {
private JLabel nameLabel;
private JLabel ageLabel;
private JButton changeDataButton;
public View() {
this.nameLabel = new JLabel();
this.ageLabel = new JLabel();
this.changeDataButton = new JButton("Change Data");
}
public JPanel createView() {
JPanel viewPanel = new JPanel(new BorderLayout());
viewPanel.add(new JLabel("View only name and age"), BorderLayout.NORTH);
viewPanel.add(nameLabel, BorderLayout.WEST);
viewPanel.add(ageLabel, BorderLayout.EAST);
viewPanel.add(changeDataButton, BorderLayout.SOUTH);
inizializeView();
return viewPanel;
}
private void inizializeView() {
this.nameLabel.setText(Database.getInstance().getDatabase().get(0).getName());
this.ageLabel.setText("" + Database.getInstance().getDatabase().get(0).getAge());
}
public void addController(Controller controller) {
changeDataButton.addActionListener(controller);
}
@Override
public void update(Observable obs, Object obj) {
nameLabel.setText(((Database) obs).getDatabase().get(0).getName());
ageLabel.setText("" + ((Database) obs).getDatabase().get(0).getAge());
}
}
Controller.java
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Controller implements ActionListener {
public Controller() {
}
@Override
public void actionPerformed(ActionEvent arg0) {
Database.getInstance().changeData("B", 30, "female"); // change model
}
}
,你可以看到,view
面板只占2/3 Person
领域。我应该为这个视图面板实现一个单独的模型,它只代表String name
和int age
的Person
或者我应该离开一切吗?
另请参阅此相关的[示例](https://stackoverflow.com/a/13919878/230513)。 – trashgod