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84 lines
2.9 KiB
84 lines
2.9 KiB
/**
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* 任务二：银行取款自定义异常
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* 文件内含：InsufficientFundsException + Account + main 测试
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*/
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// ── 自定义异常：继承 Exception（Checked，强迫调用方处理）──
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class InsufficientFundsException extends Exception {
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private final double balance; // 当前余额
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private final double amount; // 尝试取款金额
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public InsufficientFundsException(double balance, double amount) {
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super(String.format("余额不足！当前余额 %.2f 元，尝试取款 %.2f 元，差额 %.2f 元",
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balance, amount, amount - balance));
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this.balance = balance;
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this.amount = amount;
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}
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public double getBalance() { return balance; }
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public double getAmount() { return amount; }
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}
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// ── Account 类 ──
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class Account {
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private final String owner;
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private double balance;
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public Account(String owner, double initialBalance) {
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this.owner = owner;
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this.balance = initialBalance;
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}
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/**
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* 取款：余额不足时抛出 InsufficientFundsException，并携带当前余额信息
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*/
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public void withdraw(double amount) throws InsufficientFundsException {
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if (amount <= 0) {
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throw new IllegalArgumentException("取款金额必须大于 0");
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}
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if (amount > balance) {
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throw new InsufficientFundsException(balance, amount);
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}
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balance -= amount;
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System.out.printf(" 取款成功：%.2f 元，剩余余额：%.2f 元%n", amount, balance);
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}
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public double getBalance() { return balance; }
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public String getOwner() { return owner; }
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}
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// ── 测试入口 ──
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public class BankAccount {
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public static void main(String[] args) {
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Account acc = new Account("张三", 500.00);
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System.out.println("账户：" + acc.getOwner() + "，初始余额：" + acc.getBalance());
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// 正常取款
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System.out.println("\n--- 取款 200 元 ---");
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try {
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acc.withdraw(200);
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} catch (InsufficientFundsException e) {
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System.out.println(" 提示：" + e.getMessage());
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}
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// 余额不足
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System.out.println("\n--- 取款 400 元（余额不足）---");
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try {
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acc.withdraw(400);
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} catch (InsufficientFundsException e) {
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System.out.println(" 提示：" + e.getMessage());
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System.out.printf(" 当前余额：%.2f 元，建议最多取 %.2f 元%n",
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e.getBalance(), e.getBalance());
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}
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// 非法金额
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System.out.println("\n--- 取款 -50 元（非法金额）---");
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try {
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acc.withdraw(-50);
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} catch (InsufficientFundsException e) {
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System.out.println(" 提示：" + e.getMessage());
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} catch (IllegalArgumentException e) {
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System.out.println(" 错误：" + e.getMessage());
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}
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}
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}
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