多執行緒6（模擬銀行系統存錢）
1.題目
模擬一個簡單的銀行系統，使用兩個不同的執行緒向同一個帳戶存錢。
實作：使用synchronized關鍵字，將存錢的方法修改成同步的。
2.解題想法
建立一個類別：SynchronizedBankFrame，繼承JFrame類別
寫一個內部類別Bank
定義一個account變量，來表示帳戶。
deposit():一個存錢的方法
#getAccount()：顯示帳戶餘額的方法。
寫一個內部類別Transfer，實作Runnable介面
在run方法中實作向帳戶存錢的功能。
同步方法就是用synchronized關鍵字修飾的方法。
JDK為每個JAVA物件配置了內建鎖定，如果方法使用synchronized關鍵字修飾,內建鎖定就會保護整個方法。
3.程式碼詳解
SynchronizedBankFrame
package com.xiaoxuzhu;
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JButton;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.GridLayout;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import java.awt.Font;
import javax.swing.UIManager;
/**
* Description:
*
* @author xiaoxuzhu
* @version 1.0
*
* <pre class="brush:php;toolbar:false">
* 修改记录:
* 修改后版本 修改人 修改日期 修改内容
* 2022/5/14.1 xiaoxuzhu 2022/5/14 Create
*
登入後複製
* @date 2022/5/14
*/
public class SynchronizedBankFrame extends JFrame {
/**
*
*/
private static final long serialVersionUID = 2671056183299397274L;
private JPanel contentPane;
private JTextArea thread1TextArea;
private JTextArea thread2TextArea;
/**
* Launch the application.
*/
public static void main(String[] args) {
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
} catch (Throwable e) {
e.printStackTrace();
}
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SynchronizedBankFrame frame = new SynchronizedBankFrame();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public SynchronizedBankFrame() {
setTitle("使用Synchronized实现线程同步");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(new BorderLayout(0, 0));
JPanel buttonPanel = new JPanel();
contentPane.add(buttonPanel, BorderLayout.SOUTH);
JButton startButton = new JButton("开始存钱");
startButton.setFont(new Font("微软雅黑", Font.PLAIN, 16));
startButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
do_button_actionPerformed(arg0);
}
});
buttonPanel.add(startButton);
JPanel processPanel = new JPanel();
contentPane.add(processPanel, BorderLayout.CENTER);
processPanel.setLayout(new GridLayout(1, 2, 5, 5));
JPanel thread1Panel = new JPanel();
processPanel.add(thread1Panel);
thread1Panel.setLayout(new BorderLayout(0, 0));
JLabel thread1Label = new JLabel("一号线程");
thread1Label.setFont(new Font("微软雅黑", Font.PLAIN, 16));
thread1Label.setHorizontalAlignment(SwingConstants.CENTER);
thread1Panel.add(thread1Label, BorderLayout.NORTH);
JScrollPane thread1ScrollPane = new JScrollPane();
thread1Panel.add(thread1ScrollPane, BorderLayout.CENTER);
thread1TextArea = new JTextArea();
thread1TextArea.setFont(new Font("微软雅黑", Font.PLAIN, 16));
thread1ScrollPane.setViewportView(thread1TextArea);
JPanel thread2Panel = new JPanel();
processPanel.add(thread2Panel);
thread2Panel.setLayout(new BorderLayout(0, 0));
JLabel thread2Label = new JLabel("二号线程");
thread2Label.setFont(new Font("微软雅黑", Font.PLAIN, 16));
thread2Label.setHorizontalAlignment(SwingConstants.CENTER);
thread2Panel.add(thread2Label, BorderLayout.NORTH);
JScrollPane thread2ScrollPane = new JScrollPane();
thread2Panel.add(thread2ScrollPane, BorderLayout.CENTER);
thread2TextArea = new JTextArea();
thread2TextArea.setFont(new Font("微软雅黑", Font.PLAIN, 16));
thread2ScrollPane.setViewportView(thread2TextArea);
}
protected void do_button_actionPerformed(ActionEvent arg0) {
Bank bank = new Bank();
Thread thread1 = new Thread(new Transfer(bank, thread1TextArea));
thread1.start();
Thread thread2 = new Thread(new Transfer(bank, thread2TextArea));
thread2.start();
}
private class Transfer implements Runnable {
private Bank bank;
private JTextArea textArea;
public Transfer(Bank bank, JTextArea textArea) {// 初始化变量
this.bank = bank;
this.textArea = textArea;
}
public void run() {
for (int i = 0; i < 10; i++) {// 向账户中存入10次钱
bank.deposit(10);// 向账户中存入10块钱
String text = textArea.getText();// 获得文本域中的文本
// 在文本域中显示账户中的余额
textArea.setText(text + "账户的余额是：" + bank.getAccount() + "\n");
}
}
}
private class Bank {
private int account = 100;// 每个账户的初始金额是100元
public synchronized void deposit(int money) {// 向账户中存入money元
account += money;
}
public int getAccount() {// 查询账户余额
return account;
}
}
}
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