Java内部类封装方法与实战

public class BankAccount {
    private double balance;
    private String accountNumber;

    public BankAccount(String accountNumber, double initialBalance) {
        this.accountNumber = accountNumber;
        this.balance = initialBalance;
    }

    // 内部类：封装日志记录逻辑
    private class TransactionLogger {
        void log(String message) {
            System.out.println("[LOG][" + accountNumber + "] " + message);
        }
    }

    private TransactionLogger logger = new TransactionLogger();

    public void deposit(double amount) {
        balance += amount;
        logger.log("Deposit: +" + amount);
    }

    public void withdraw(double amount) {
        if (amount 

public void processUserData(String data) {
    class DataValidator {
        boolean isValid() {
            return data != null && data.trim().length() > 5;
        }

        String sanitize() {
            return data.trim().toUpperCase();
        }
    }

    DataValidator validator = new DataValidator();
    if (validator.isValid()) {
        System.out.println("Processing: " + validator.sanitize());
    } else {
        System.out.println("Invalid data");
    }
}

public class DatabaseManager {
    private String host;
    private int port;

    public DatabaseManager(String configString) {
        ConfigParser parser = new ConfigParser();
        host = parser.getHost(configString);
        port = parser.getPort(configString);
    }

    // 静态内部类：独立的配置解析工具
    private static class ConfigParser {
        String getHost(String config) {
            // 解析逻辑
            return config.split(":")[0];
        }

        int getPort(String config) {
            return Integer.parseInt(config.split(":")[1]);
        }
    }
}