在Java中如何使用内部类封装实现细节_OOP内部类封装方法分享

public class BankAccount {
    private double balance;

    public BankAccount(double balance) {
        this.balance = balance;
    }

    // 内部类负责交易验证
    private class TransactionValidator {
        boolean isValid(double amount) {
            return amount > 0 && amount <= balance;
        }
    }

    public void withdraw(double amount) {
        TransactionValidator validator = new TransactionValidator();
        if (validator.isValid(amount)) {
            balance -= amount;
            System.out.println("取款成功：" + amount);
        } else {
            System.out.println("取款失败：金额无效");
        }
    }
}

public class BankAccount {
    // 静态内部类用于状态解析
    public static class StatusParser {
        public static String parse(int code) {
            switch (code) {
                case 1: return "正常";
                case 2: return "冻结";
                default: return "未知";
            }
        }
    }
}
// 使用方式
String status = BankAccount.StatusParser.parse(1);

public void processTransaction(Runnable callback) {
    // 模拟处理逻辑
    System.out.println("正在处理交易...");
    
    // 匿名内部类作为回调
    callback.run();
}
// 调用时传入匿名实现
processTransaction(new Runnable() {
    public void run() {
        System.out.println("交易完成通知已发送");
    }
});