第九天 企业进销存系统

深入面向对象

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案例：企业进销存系统

1. 接口：在Java中，接口是实现可插入特性的保证。定义接口的关键字是interface，实现接口的关键字是implements，一个类可以实现多个接口，接口之间的继承支持多重继承。
2. 接口和抽象类的异同
   关键字对比
   接口：声明接口： interface + 接口名（命名方式同类），实现：创建实现类 + implements + 接口名（）；实现类：必须重写接口未实现的方法。

抽象类：声明抽象类：abstract + class +类名 。同时必须声明抽象方法：abstract +void +方法名（）；子类：继承抽象类的子类必须重写抽象方法。

1. 类/类和类/接口之间的关系
   
   • IS-A关系：继承/实现
   • HAS-A关系：关联/聚合（聚集）/合成
   • USE-A关系：依赖
2. UML：统一建模语言（标准的图形化符号）
   
   • 类图：描述类以及类和类之间关系的图形符号。
   • 用例图：捕获需求。
   • 时序图：描述对象交互关系。
3. 面向对象的设计原则
   
   • 单一职责原则（SRP）：类的设计要做到高内聚，一个类只承担单一的职责（不做不该它做的事情）。
   • 开闭原则（OCP）：软件系统应该接受扩展（对扩展开放），不接受修改（对修改关闭）。要符合开闭原则：抽象是关键，封装可变性。
   • 依赖倒转原则（DIP）：面向接口编程。声明变量的引用类型，声明方法的参数类型，声明方法的返回类型时，尽可能使用抽象类型而不是具体类型。
   • 里氏替换原则（LSP）：用子类型替换父类型没有任何问题，用父类型替换子类型通常都是不行的。
   • 接口隔离原则（ISP）：接口要小而专，不能大而全。
   • 合成聚合复用原则（CARP）：优先考虑用强关联关系复用代码，而不是用继承关系复用代码。
   • 迪米特法则（LoD）：对象之间尽可能少的发生联系。

package com.lovoinfo.ui;/**/*登录器与主窗口分段隐藏*/import java.awt.Graphics;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.util.ArrayList;import java.util.List;import javax.swing.JButton;import javax.swing.JDialog;import javax.swing.JLabel;import javax.swing.JOptionPane;import javax.swing.JPasswordField;import javax.swing.JTextField;/**/*登录窗口@SuppressWarnings("serial")public class LoginFrame extends JDialog {    private JLabel uidLabel, pwdLabel;    private JTextField uidField;    private JPasswordField pwdField;    private JButton loginButton, cancelButton;    private List<User> userList = new ArrayList<User>();//用户容器    public LoginFrame() {        this.setTitle("用户登录");        this.setSize(300, 180);        this.setResizable(false);        this.setLocationRelativeTo(null);        // this.setDefaultCloseOperation(HIDE_ON_CLOSE);//隐藏窗口        initComponents();    }    @Override    public void paint(Graphics g) {        super.paint(g);    }    private boolean checkLogin(String username, String password) {        for(User user : userList) {            if(user.getUsername().equals(username)) {                return user.getPassword().equals(password);            }        }        return false;    }    private void initComponents() {        userList.add(new User("admin", "123456"));        userList.add(new User("hellokitty", "1qaz2wsx"));        userList.add(new User("jack", "123123"));        uidLabel = new JLabel("用户名: ");        pwdLabel = new JLabel("密码: ");        uidField = new JTextField();        pwdField = new JPasswordField();        loginButton = new JButton("登录");        loginButton.addActionListener(new ActionListener() {            @Override            public void actionPerformed(ActionEvent e) {                String username = uidField.getText().trim();                String password = new String(pwdField.getPassword());                if(checkLogin(username, password)) {                    LoginFrame.this.setVisible(false);                    new MainFrame(LoginFrame.this).setVisible(true);                }                else {                    JOptionPane.showMessageDialog(null, "用户名或密码错误", "错误", 0);                }            }        });        cancelButton = new JButton("取消");        cancelButton.addActionListener(new ActionListener() {            @Override            public void actionPerformed(ActionEvent e) {                System.exit(0);            }        });        this.setLayout(null);        uidLabel.setBounds(40, 20, 50, 30);        pwdLabel.setBounds(40, 60, 50, 30);        uidField.setBounds(100, 25, 150, 20);        pwdField.setBounds(100, 65, 150, 20);        loginButton.setBounds(80, 100, 60, 30);        cancelButton.setBounds(160, 100, 60, 30);        this.add(uidLabel);        this.add(pwdLabel);        this.add(uidField);        this.add(pwdField);        this.add(loginButton);        this.add(cancelButton);    }}

用户类

package com.lovoinfo.ui;public class User {    private String username;    private String password;    public User(String username, String password) {        this.username = username;        this.password = password;    }    public String getUsername() {        return username;    }    public String getPassword() {        return password;    }}

主窗口

package com.lovoinfo.ui;import java.awt.Component;import java.awt.Font;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JButton;import javax.swing.JInternalFrame;import javax.swing.JLabel;import javax.swing.JOptionPane;import javax.swing.JPasswordField;import javax.swing.JTextField;import com.lovoinfo.biz.impl.UserServiceImpl;import com.lovoinfo.domain.User;/** * 注册窗口(单例类) * @author jackfrued * */@SuppressWarnings("serial")public class RegInternalFrame extends JInternalFrame {    private class ButtonHandler implements ActionListener {        @Override        public void actionPerformed(ActionEvent e) {            if(e.getSource() == regButton) {                String username = uidField.getText().trim();                String password = new String(pwdField.getPassword());                String email = emailField.getText().trim();                User user = new User(username, password, email);                user.setUserService(new UserServiceImpl());                if(user.register()) {                    JOptionPane.showMessageDialog(null, "注册成功!");                    reset();                    RegInternalFrame.this.setVisible(false);                }                else {                    JOptionPane.showMessageDialog(null, "注册失败!", "错误提示",  0);                }            }            else if(e.getSource() == resetButton) {                reset();            }        }    }    private static Font defaultFont = new Font("微软雅黑", Font.PLAIN, 14);    private String[] labelNames = {"用户名: ", "密码: ", "确认密码: ", "电子邮箱: "};    private JLabel[] labels = new JLabel[4];    private JTextField uidField, emailField;    private JPasswordField pwdField, rePwdField;    private JButton regButton, resetButton;    private RegInternalFrame() {        super("用户注册", false, true, false, false);        this.setSize(270, 300);        this.setLocation(50, 50);        this.setVisible(true);        this.setDefaultCloseOperation(HIDE_ON_CLOSE);        initComponents();    }    private static RegInternalFrame instance = new RegInternalFrame();    public static RegInternalFrame getInstance() {        return instance;    }    private void initComponents() {        this.setLayout(null);        for(int i = 0; i < labels.length; i++) {            labels[i] = new JLabel(labelNames[i]);            labels[i].setBounds(20, 30 + 48 * i, 70, 24);            this.add(labels[i]);        }        uidField = new JTextField();        uidField.setBounds(100, 30, 120, 24);        this.add(uidField);        pwdField = new JPasswordField();        pwdField.setBounds(100, 78, 120, 24);        this.add(pwdField);        rePwdField = new JPasswordField();        rePwdField.setBounds(100, 126, 120, 24);        this.add(rePwdField);        emailField = new JTextField();        emailField.setBounds(100, 174, 150, 24);        this.add(emailField);        ActionListener handler = new ButtonHandler();        regButton = new JButton("注册");        regButton.setBounds(60, 230, 70, 24);        regButton.addActionListener(handler);        this.add(regButton);        resetButton = new JButton("重置");        resetButton.setBounds(150, 230, 70, 24);        resetButton.addActionListener(handler);        this.add(resetButton);        // 为窗口上的所有控件设置统一的字体        for(Component c : this.getContentPane().getComponents()) {            c.setFont(defaultFont);        }    }    private void reset() {        // 为窗口上的所有控件设置统一的字体        for(Component c : RegInternalFrame.this.getContentPane().getComponents()) {            if(c instanceof JTextField) {                ((JTextField) c).setText("");            }            else if(c instanceof JPasswordField) {                ((JPasswordField) c).setText("");            }        }    }}

package com.lovoinfo.ui;import java.awt.FlowLayout;import java.awt.event.MouseAdapter;import java.awt.event.MouseEvent;import javax.swing.ImageIcon;import javax.swing.JLabel;import javax.swing.JPanel;@SuppressWarnings("serial")public class SysManPanel extends JPanel {    private class MouseHandler extends MouseAdapter {        private int index;        public MouseHandler(int index) {            this.index = index;        }        @Override        public void mouseEntered(MouseEvent e) {            labels[index].setIcon(new ImageIcon(buttonRollImageNames[index]));        }        @Override        public void mouseExited(MouseEvent e) {            labels[index].setIcon(new ImageIcon(buttonImageNames[index]));        }        @Override        public void mousePressed(MouseEvent e) {            labels[index].setIcon(new ImageIcon(buttonDownImageNames[index]));        }        @Override        public void mouseReleased(MouseEvent e) {            labels[index].setIcon(new ImageIcon(buttonRollImageNames[index]));        }        @Override        public void mouseClicked(MouseEvent e) {            RegInternalFrame frame = RegInternalFrame.getInstance();            if(mainFrame.containsInternalFrame(frame)) {                mainFrame.showInternalFrame(frame);            }            else {                mainFrame.addInternalFrame(frame);            }        }    }    private static String[] buttonImageNames = {        "操作员管理.png", "更改密码.png", "权限管理.png"    };    private static String[] buttonRollImageNames = {        "操作员管理_roll.png", "更改密码_roll.png", "权限管理_roll.png"    };    private static String[] buttonDownImageNames = {        "操作员管理_down.png", "更改密码_down.png", "权限管理_down.png"    };    private JLabel[] labels = new JLabel[3];    private MainFrame mainFrame;    public SysManPanel(MainFrame mainFrame) {        this.mainFrame = mainFrame;        this.setLayout(new FlowLayout(FlowLayout.LEFT));        for(int i = 0; i < labels.length; i++) {            labels[i] = new JLabel(new ImageIcon(buttonImageNames[i]));            labels[i].addMouseListener(new MouseHandler(i));            this.add(labels[i]);        }    }}

package com.lovoinfo.ui;import java.awt.Graphics;import javax.swing.ImageIcon;import javax.swing.JDesktopPane;@SuppressWarnings("serial")public class MyDesktopPane extends JDesktopPane {    private static ImageIcon bgImage = new ImageIcon("welcome.jpg");    @Override    public void paintComponent(Graphics g) {        super.paintComponent(g);        g.drawImage(bgImage.getImage(), 0, 0, this.getWidth(), this.getHeight(), null);    }}

用户类及服务类

package com.lovoinfo.domain;import com.lovoinfo.biz.UserService;public class User {    private String username;    private String password;    private String email;    private UserService userService;    public User() {    }    public User(String username, String password) {        this.username = username;        this.password = password;    }    public User(String username, String password, String email) {        this.username = username;        this.password = password;        this.email = email;    }    public boolean login() {        return userService.doLogin(this);    }    public boolean register() {        return userService.doRegister(this);    }    public void setUserService(UserService userService) {        this.userService = userService;    }    public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    public String getEmail() {        return email;    }    public void setEmail(String email) {        this.email = email;    }}

package com.lovoinfo.biz;import com.lovoinfo.domain.User;/** * 用户业务逻辑接口 * @author jackfrued * */public interface UserService {    /**     * 登录     * @param user 用户对象     * @return 登录成功返回true否则返回false     */    public boolean doLogin(User user);    /**     * 注册     * @param user 用户对象     * @return 注册成功返回true否则返回false     */    public boolean doRegister(User user);}

package com.lovoinfo.biz.impl;import java.util.ArrayList;import java.util.List;import com.lovoinfo.biz.UserService;import com.lovoinfo.domain.User;/** * 用户业务逻辑实现类 * @author jackfrued * */public class UserServiceImpl implements UserService {    private static List<User> userList = new ArrayList<User>();    static {        userList.add(new User("admin", "123456"));        userList.add(new User("jack", "abcdefg"));    }    public UserServiceImpl() {    }    @Override    public boolean doLogin(User user) {        User temp = findUserByUsername(user.getUsername());        if(temp != null) {            return temp.getPassword().equals(user.getPassword());        }        return false;    }    @Override    public boolean doRegister(User user) {        User temp = findUserByUsername(user.getUsername());        if(temp == null) {            userList.add(user);            return true;        }        return false;    }    // 根据用户名查找用户    private User findUserByUsername(String username) {        for(User temp : userList) {            if(temp.getUsername().equals(username)) {                return temp;            }        }        return null;    }}