进阶day05-自定义异常-银行案例

javaSE-day05/src/com/inmind/custom_exception06/Account.java

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+package com.inmind.custom_exception06;
+
+//账户类
+public class Account {
+    String id;//账户ID
+    String name;
+    double balance;
+    int pwdErrors;//密码输错次数
+    boolean locked;//是否是锁定状态
+
+    static final int MAX_PWD_ERROR = 3;//最大密码错误次数
+    static final String PWD = "123456";//默认密码
+
+    public Account(String id, String name, double balance) {
+        this.id = id;
+        this.name = name;
+        this.balance = balance;
+    }
+
+    //存款功能
+    public void saveMoney(double balance) throws AccountLockedException, InvalidAmountException {
+        if (this.locked) {
+            throw new AccountLockedException("账户"+this.id+"已锁定");
+        }
+        if (balance <= 0) {
+            throw new InvalidAmountException("存款必须大于0");
+        }
+        this.balance += balance;
+        System.out.println(this.name+"存了"+balance+"元，当前余额为"+this.balance+"元");
+    }
+
+    // 取款
+    public void getMoney(double amount, String pwd) throws Exception {
+        if (locked) throw new AccountLockedException("账户" + id + "已锁定");
+        // 密码验证
+        if (!PWD.equals(pwd)) {
+            pwdErrors++;
+            System.out.println("pwdErrors的值" + pwdErrors);
+            if (pwdErrors >= MAX_PWD_ERROR) {
+                locked = true;
+                throw new AccountLockedException("密码错误3次，账户" + id + "已锁定");
+            }
+            throw new Exception("密码错误，剩余次数：" + (MAX_PWD_ERROR - pwdErrors));
+        }
+        if (amount <= 0) throw new InvalidAmountException("取款金额必须大于0");
+        if (amount > balance) throw new NotEnoughException("余额不足，当前余额：" + balance);
+        balance -= amount;
+        System.out.println(name + "取款" + amount + "元，当前余额：" + balance);
+    }
+
+
+}

javaSE-day05/src/com/inmind/custom_exception06/AccountLockedException.java

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+package com.inmind.custom_exception06;
+// 自定义异常3：账户锁定异常
+public class AccountLockedException extends Exception{
+    public AccountLockedException(String message) {
+        super(message);
+    }
+}

javaSE-day05/src/com/inmind/custom_exception06/Bank.java

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+package com.inmind.custom_exception06;
+
+// 银行类
+class Bank {
+    private Account[] accounts;  // 账户数组
+    private int count;           // 账户数量
+    private static final double MAX_TRANSFER = 50000;  // 单笔最大转账额
+
+    // 构造方法
+    public Bank(int size) {
+        accounts = new Account[size];
+        count = 0;
+    }
+
+    // 创建账户
+    public void addAccount(Account acc) {
+        if (count < accounts.length) {
+            accounts[count++] = acc;
+            System.out.println("创建账户成功：" + acc.id + "(" + acc.name + ")");
+        }
+    }
+
+    // 查找账户
+    public Account findAccount(String id) throws Exception {
+        for (int i = 0; i < count; i++) {
+            if (accounts[i].id.equals(id)) {
+                return accounts[i];
+            }
+        }
+        throw new Exception("账户" + id + "不存在");
+    }
+
+    // 转账
+    public void transferMoney(String fromId, String toId, double amount, String pwd) throws Exception {
+        Account from = findAccount(fromId);
+        Account to = findAccount(toId);
+
+        if (amount <= 0) throw new InvalidAmountException("转账金额必须大于0");
+        if (amount > MAX_TRANSFER) throw new TransferLimitException("超过最大转账额" + MAX_TRANSFER);
+
+        from.getMoney(amount, pwd);  // 先取款
+        to.saveMoney(amount);          // 再存款
+        System.out.println("从" + from.name + "向" + to.name + "转账" + amount + "元成功");
+    }
+}

javaSE-day05/src/com/inmind/custom_exception06/InvalidAmountException.java

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+package com.inmind.custom_exception06;
+// 自定义异常2：无效金额异常
+public class InvalidAmountException extends Exception{
+    public InvalidAmountException(String message) {
+        super(message);
+    }
+}

javaSE-day05/src/com/inmind/custom_exception06/NotEnoughException.java

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+package com.inmind.custom_exception06;
+
+//余额不足异常
+public class NotEnoughException extends Exception{
+    public NotEnoughException(String message) {
+        super(message);
+    }
+}

javaSE-day05/src/com/inmind/custom_exception06/Test12.java

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+package com.inmind.custom_exception06;
+
+import java.sql.SQLOutput;
+
+/*
+自定义异常（4 个）：
+NotEnoughException：余额不足时抛出
+InvalidAmountException：金额为负数或零时抛出
+AccountLockedException：账户锁定时抛出
+TransferLimitException：转账超过限额时抛出
+
+核心功能：
+存款：验证账户状态和金额有效性
+取款：验证密码（3 次错误锁定）、金额和余额
+转账：校验双方账户、金额和限额，包含取款 + 存款原子操作
+
+业务规则：
+密码错误 3 次自动锁定账户
+单笔转账上限 5000 元
+不允许负金额交易
+锁定账户无法进行任何操作
+ */
+public class Test12 {
+    public static void main(String[] args) {
+        Bank bank = new Bank(10);
+        try {
+            // 创建账户
+            bank.addAccount(new Account("1001", "张三", 10000));
+            bank.addAccount(new Account("1002", "李四", 5000));
+
+            Account zhang = bank.findAccount("1001");
+            // 正常操作
+            zhang.saveMoney(2000);
+            zhang.getMoney(3000, "123456");
+
+            // 测试异常场景
+            try {
+                zhang.getMoney(20000, "123456");
+            }  // 余额不足
+            catch (NotEnoughException e) {
+                System.out.println("异常：" + e.getMessage());
+            }
+
+            try {
+                bank.transferMoney("1001", "1002", 60000, "123456");
+            }  // 转账超限
+            catch (TransferLimitException e) {
+                System.out.println("异常：" + e.getMessage());
+            }
+
+            try {
+                zhang.getMoney(1000, "111");
+            }  // 密码错误
+            catch (Exception e) {
+                System.out.println("异常：" + e.getMessage());
+            }
+
+            try {
+                zhang.getMoney(1000, "111");
+            }  // 锁定账户
+            catch (Exception e) {
+                System.out.println("异常：" + e.getMessage());
+            }
+            try {
+                zhang.getMoney(1000, "111");
+            }  // 锁定账户
+            catch (AccountLockedException e) {
+                System.out.println("异常：" + e.getMessage());
+            }
+
+            try {
+                zhang.getMoney(1000, "111");
+            }  // 锁定账户
+            catch (AccountLockedException e) {
+                System.out.println("异常：" + e.getMessage());
+            }
+
+        } catch (Exception e) {
+            System.out.println("系统错误：" + e.getMessage());
+        }
+    }
+}

javaSE-day05/src/com/inmind/custom_exception06/TransferLimitException.java

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+package com.inmind.custom_exception06;
+
+// 自定义异常4：转账超限异常
+public class TransferLimitException extends Exception{
+    public TransferLimitException(String message) {
+        super(message);
+    }
+}