大话设计模式——策略模式
Posted 不见长安见晨雾
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1）商场收银系统
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JTextField;
/**
* 商场收银系统
*/
@SuppressWarnings("serial")
public class Mall implements ActionListener
private static JLabel unitPriceLabel;
private static JTextField unitPriceValue;
private static JLabel numLabel;
private static JTextField numValue;
private double totalPrice = 0;
private static JList<String> jList;
private static DefaultListModel<String> listModel;
private static JLabel totalNum;
public static void main(String[] args)
JFrame frame = new JFrame("商城收银系统");
frame.setSize(450, 400);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
frame.add(panel);
placeComponents(panel);
frame.setVisible(true);
private static void placeComponents(JPanel panel)
panel.setLayout(null);
Mall mainFrame = new Mall();
// 第一行
unitPriceLabel = new JLabel("单价：");
unitPriceLabel.setBounds(10, 20, 80, 25);
panel.add(unitPriceLabel);
unitPriceValue = new JTextField(20);
unitPriceValue.setBounds(100, 20, 165, 25);
panel.add(unitPriceValue);
JButton confirmButton = new JButton("确定");
confirmButton.setBounds(280, 20, 80, 25);
confirmButton.addActionListener(mainFrame);
confirmButton.setActionCommand("confirm");
panel.add(confirmButton);
// 第二行
numLabel = new JLabel("数量：");
numLabel.setBounds(10, 50, 80, 25);
panel.add(numLabel);
numValue = new JTextField(20);
numValue.setBounds(100, 50, 165, 25);
panel.add(numValue);
JButton resetButton = new JButton("重置");
resetButton.setBounds(280, 50, 80, 25);
resetButton.addActionListener(mainFrame);
resetButton.setActionCommand("reset");
panel.add(resetButton);
// 第三行
listModel = new DefaultListModel<String>();
jList = new JList<String>(listModel);
jList.setBounds(10, 90, 400, 180);
panel.add(jList);
// 第四行
JLabel totalLabel = new JLabel("总计：");
totalLabel.setBounds(10, 300, 80, 25);
panel.add(totalLabel);
totalNum = new JLabel("0.00");
totalNum.setBounds(100, 300, 80, 25);
panel.add(totalNum);
@Override
public void actionPerformed(ActionEvent event)
if (event.getActionCommand().equals("confirm"))
double unitPrice = Double.parseDouble(unitPriceValue.getText());
double num = Double.parseDouble(numValue.getText());
double total = unitPrice * num;
listModel.addElement("单价："+unitPriceValue.getText()+" 数量："+numValue.getText() +" 合计："+total);
totalPrice +=total;
totalNum.setText(totalPrice+"");
else if(event.getActionCommand().equals("reset"))
unitPriceValue.setText("");
numValue.setText("");
listModel.clear();
totalPrice=0;
totalNum.setText(totalPrice+"");
执行效果
2）增加打折功能
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JTextField;
/**
* 需求：增加打折功能
*/
@SuppressWarnings("serial")
public class Mall implements ActionListener
private static JLabel unitPriceLabel;
private static JTextField unitPriceValue;
private static JLabel numLabel;
private static JTextField numValue;
private double totalPrice = 0;
private static JList<String> jList;
private static DefaultListModel<String> listModel;
private static JLabel totalNum;
private static JLabel calcType;
private static JComboBox<String> jComboBox;
public static void main(String[] args)
JFrame frame = new JFrame("商城收银系统");
frame.setSize(450, 400);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
frame.add(panel);
placeComponents(panel);
frame.setVisible(true);
private static void placeComponents(JPanel panel)
panel.setLayout(null);
Mall mainFrame = new Mall();
// 第一行
unitPriceLabel = new JLabel("单价：");
unitPriceLabel.setBounds(10, 20, 80, 25);
panel.add(unitPriceLabel);
unitPriceValue = new JTextField(20);
unitPriceValue.setBounds(100, 20, 165, 25);
panel.add(unitPriceValue);
JButton confirmButton = new JButton("确定");
confirmButton.setBounds(280, 20, 80, 25);
confirmButton.addActionListener(mainFrame);
confirmButton.setActionCommand("confirm");
panel.add(confirmButton);
// 第二行
numLabel = new JLabel("数量：");
numLabel.setBounds(10, 50, 80, 25);
panel.add(numLabel);
numValue = new JTextField(20);
numValue.setBounds(100, 50, 165, 25);
panel.add(numValue);
JButton resetButton = new JButton("重置");
resetButton.setBounds(280, 50, 80, 25);
resetButton.addActionListener(mainFrame);
resetButton.setActionCommand("reset");
panel.add(resetButton);
// 第三行
calcType = new JLabel("计算方式：");
calcType.setBounds(10, 90, 80, 25);
panel.add(calcType);
jComboBox = new JComboBox<String>();
jComboBox.insertItemAt("正常收费", 0);
jComboBox.insertItemAt("打八折", 1);
jComboBox.insertItemAt("打七折", 2);
jComboBox.insertItemAt("打五折", 3);
jComboBox.setSelectedIndex(0);
jComboBox.setBounds(100, 90, 80, 25);
panel.add(jComboBox);
// 第四行
listModel = new DefaultListModel<String>();
jList = new JList<String>(listModel);
jList.setBounds(10, 120, 400, 180);
panel.add(jList);
// 第五行
JLabel totalLabel = new JLabel("总计：");
totalLabel.setBounds(10, 300, 80, 25);
panel.add(totalLabel);
totalNum = new JLabel("0.00");
totalNum.setBounds(100, 300, 80, 25);
panel.add(totalNum);
@Override
public void actionPerformed(ActionEvent event)
if (event.getActionCommand().equals("confirm"))
double unitPrice = Double.parseDouble(unitPriceValue.getText());
double num = Double.parseDouble(numValue.getText());
int selectedIndex = jComboBox.getSelectedIndex();
double total = 0;
switch (selectedIndex)
case 0:
total = unitPrice * num;
break;
case 1:
total = unitPrice * num * 0.8;
break;
case 2:
total = unitPrice * num * 0.7;
break;
case 3:
total = unitPrice * num * 0.5;
break;
totalPrice += total;
listModel.addElement("单价：" + unitPriceValue.getText() + " 数量：" + numValue.getText() + " "
+ jComboBox.getSelectedItem() + " 合计：" + total);
totalNum.setText(totalPrice + "");
else if (event.getActionCommand().equals("reset"))
unitPriceValue.setText("");
numValue.setText("");
listModel.clear();
totalPrice = 0;
totalNum.setText(totalPrice + "");
执行效果
3）简单工厂实现
问题：如果增加满300返100的促销算法，该如何处理？
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JTextField;
@SuppressWarnings("serial")
public class Mall implements ActionListener
private static JLabel unitPriceLabel;
private static JTextField unitPriceValue;
private static JLabel numLabel;
private static JTextField numValue;
private double totalPrice = 0;
private static JList<String> jList;
private static DefaultListModel<String> listModel;
private static JLabel totalNum;
private static JLabel calcType;
private static JComboBox<String> jComboBox;
public static void main(String[] args)
JFrame frame = new JFrame("商城收银系统");
frame.setSize(450, 400);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation以上是关于大话设计模式——策略模式的主要内容，如果未能解决你的问题，请参考以下文章