Java基於對象流實現銀行系統
Java基於對象流實現銀行系統的具體代碼，供大傢參考，具體內容如下
系統特點：
- 數據持久化到文件中，系統啟動後，加載文件中數據到集合中，相當於做瞭一個緩存。
- 文件讀寫使用的是對象流（ObjectInputStream和ObjectOutputStream），用戶是看不懂那些文件的，一定程度上保證瞭密碼和餘額的安全性。
- 采用瞭MVC分層設計思想，雖然沒有C控制層和V視圖層，但是有完備的M模型層，數據處理Service，數據讀寫Dao，數據存儲POJO（每一層隻負責處理自己的事情，層次內部的改動不會影響其他層次）。
- 雖然有些細節問題由於時間關系沒有處理好，比如沒有處理輸入類型不匹配的異常，但是絕大多數功能都合理得實現瞭。
全部代碼
pojo：
public class User implements Serializable {
private static final long serialVersionUID = -7019656536540026883L;
private String username;//用戶名
private String password;//密碼
private Double balance;//餘額
public User(String username, String password, Double balance) {
this.username = username;
this.password = password;
this.balance = balance;
}
public User() {
}
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 Double getBalance() {
return balance;
}
public void setBalance(Double balance) {
this.balance = balance;
}
public String toString(){
StringBuilder builder = new StringBuilder("{");
builder.append(this.username).append(",").append(this.password).append(",").append(this.balance).append("}");
return builder.toString();
}
dao層：
public class ATMDao {
private String userFilePath = "src\\userMsg.txt";//相對路徑
private HashMap<String, User> userMsg;
{
userMsg = this.loadFile();//讀取文件信息
}
public HashMap<String, User> getUserMsg() {
return userMsg;
}
//查詢用戶
public User selectUser(String username){
return userMsg.get(username);
}
//更新用戶信息
public void updateUser(User user){
this.userMsg.replace(user.getUsername(),user);
this.updateFile(userMsg);
}
//增加用戶
public void addUser(User user){
this.userMsg.put(user.getUsername(),user);
this.updateFile(userMsg);
}
//刪除用戶
public void deleteUser(User user){
this.userMsg.remove(user.getUsername());
this.updateFile(userMsg);
}
//隻在初始化時時調用一次
/* public void initFile(){
User user1 = new User("張三","123",800.0);
User user2 = new User("李四","666",70.0);
User user3 = new User("王五","888",555.0);
userMsg.put(user1.getUsername(),user1);
userMsg.put(user2.getUsername(),user2);
userMsg.put(user3.getUsername(),user3);
this.updateFile(userMsg);
}*/
private HashMap<String, User> loadFile(){
File file = new File(userFilePath);
FileInputStream fis = null;
ObjectInputStream ois = null;
HashMap<String, User> box = null;
try {
fis = new FileInputStream(file);
ois = new ObjectInputStream(fis);
try {
box = (HashMap<String, User>)ois.readObject();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}finally {
try {
if(fis!=null)
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if(ois!=null)
ois.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return box;
}
private void updateFile(HashMap<String,User> userMsg){
File file = new File(userFilePath);
FileOutputStream fos = null;
ObjectOutputStream oos = null;
try {
fos = new FileOutputStream(file);
oos = new ObjectOutputStream(fos);
oos.writeObject(userMsg);
oos.flush();
} catch (IOException e) {
e.printStackTrace();
}finally {
try {
if(fos!=null)
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if(oos!=null)
oos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
service層：
public class ATMService {
ATMDao dao = new ATMDao();
public boolean login(String username,String password){
User user = dao.selectUser(username);
if (user!=null && user.getPassword().equals(password))
return true;
else
return false;
}
//查詢餘額
public Double queryBalance(String name){
User user = dao.selectUser(name);
return user.getBalance();
}
//存款
public void deposit(String name,Double account){
User user = dao.selectUser(name);
user.setBalance(user.getBalance()+account);
dao.updateUser(user);
}
//取款
public void withdrawal(String name,Double account){
User user = dao.selectUser(name);
if (user.getBalance()>=account) {
user.setBalance(user.getBalance() - account);
dao.updateUser(user);
}else {
System.err.println("對不起，"+user.getUsername()+"，您的餘額不足");
}
}
//轉賬
public void transfer(String oldName,String newName,Double account){
User oldUser = dao.selectUser(oldName);
User newUser = dao.selectUser(newName);
if (newUser!=null){
if (oldUser.getBalance()>=account){
oldUser.setBalance(oldUser.getBalance()-account);
newUser.setBalance(newUser.getBalance()+account);
dao.updateUser(oldUser);
dao.updateUser(newUser);
}else {
System.err.println("對不起，"+oldUser.getUsername()+"，您的餘額不足");
}
}else {
System.err.println("對不起，您輸入的賬號不存在");
}
}
//銷戶
public void closeAccount(String name){
User u = dao.selectUser(name);
dao.deleteUser(u);
}
//註冊
public void register(String name,String password){
User user = dao.selectUser(name);
if (user!=null){
System.err.println("對不起，您輸入的賬號已存在");
}else {
user = new User(name,password,0.0);
dao.addUser(user);
}
}
}
測試：
public class Test {
public static void main(String[] args) {
ATMService service = new ATMService();
Scanner input = new Scanner(System.in);
System.out.println("歡迎您使用銀行自助服務系統\n請輸入您的賬號:");
String username = input.nextLine();
System.out.println("請輸入您的密碼：");
String password = input.nextLine();
if (service.login(username,password)){
System.out.println("登錄成功!");
while(true) {
System.out.println("請選擇您的操作：\n0.註冊\n1.查詢餘額\n2.存款\n3.取款\n4.轉賬\n5.銷戶\n6.退出");
String option = input.nextLine();
switch (option) {
case "0":
System.out.println("請輸入您的用戶名：");
String newname = input.nextLine();
System.out.println("請輸入您的密碼：");
String newPass = input.nextLine();
service.register(newname, newPass);
System.out.println("恭喜您，註冊成功！，您的用戶名為" + newname);
break;
case "1":
Double balance = service.queryBalance(username);
System.out.println("您的餘額為" + balance);
break;
case "2":
System.out.println("請輸入存款金額：");
double amount = input.nextDouble();
input.nextLine();
service.deposit(username, amount);
System.out.println("恭喜您，存款成功");
break;
case "3":
System.out.println("請輸入取款金額：");
double d = input.nextDouble();
input.nextLine();
service.withdrawal(username, d);
System.out.println("恭喜您，取款成功");
break;
case "4":
System.out.println("請輸入對方賬戶：");
String anothername = input.nextLine();
System.out.println("請輸入轉賬金額：");
double t = input.nextDouble();
input.nextLine();
service.transfer(username, anothername, t);
System.out.println("恭喜您，轉賬成功");
break;
case "5":
service.closeAccount(username);
System.out.println("銷戶成功");
break;
case "6":
System.exit(0);
}
}
}else {
System.err.println("用戶名或密碼錯誤");
}
//dao.initFile();
/*HashMap<String, User> userMsg = dao.getUserMsg();
Iterator<String> iterator = userMsg.keySet().iterator();
while (iterator.hasNext()){
String username = iterator.next();
User user = userMsg.get(username);
System.out.println(user);
}*/
}
}
部分測試截圖
以上就是本文的全部內容，希望對大傢的學習有所幫助，也希望大傢多多支持WalkonNet。