How to perform code refactoring and modular design in Java development

How to carry out code refactoring and modular design in Java development

Abstract: In Java development, code refactoring and modular design are very important. It can improve the maintainability and readability of the code. This article will introduce some common code refactoring techniques and modular design principles, and illustrate them through specific code examples.

Introduction: As the project continues to develop and the code is continuously iterated, the code will gradually become bloated and difficult to maintain. In order to solve this problem, we need to carry out code refactoring and modular design. Code refactoring refers to optimizing the existing code structure and design to improve code quality without changing the function of the code; while modular design refers to splitting a large system into multiple independent modules. To improve code reusability and maintainability.

1. Code Reconstruction

1. Extraction method: When a method is too long or contains too much logic, part of the logic can be extracted to form a new method . This improves code readability and maintainability.

// 重构前
public void processOrder(Order order) {
  // ...
  // 处理订单的业务逻辑代码
  // ...
}

// 重构后
public void processOrder(Order order) {
  validateOrder(order);
  calculateTotalAmount(order);
  saveOrder(order);
}

private void validateOrder(Order order) {
  // 验证订单
}

private void calculateTotalAmount(Order order) {
  // 计算订单总金额
}

private void saveOrder(Order order) {
  // 保存订单
}

2. Merge duplicate code: When there is repeated logic in the code, it can be extracted into a common method to reduce code redundancy.

// 重构前
public void login(String username, String password) {
  // ...
  // 登录逻辑代码
  // ...
}

public void register(String username, String password) {
  // ...
  // 注册逻辑代码
  // ...
}

// 重构后
public void authenticate(String username, String password) {
  // ...
  // 鉴权逻辑代码
  // ...
}

public void login(String username, String password) {
  authenticate(username, password);
  // ...
  // 登录逻辑代码
  // ...
}

public void register(String username, String password) {
  authenticate(username, password);
  // ...
  // 注册逻辑代码
  // ...
}

3. Split complex methods: When a method is too complex to be understood at a glance, it can be split into multiple simple methods to improve the readability of the code.

// 重构前
public void processOrder(Order order) {
  // ...
  // 复杂的订单处理逻辑代码
  // ...
}

// 重构后
public void processOrder(Order order) {
  validateOrder(order);
  calculateTotalAmount(order);
  processPayment(order);
  sendNotification(order);
}

private void validateOrder(Order order) {
  // 验证订单
}

private void calculateTotalAmount(Order order) {
  // 计算订单总金额
}

private void processPayment(Order order) {
  // 处理付款
}

private void sendNotification(Order order) {
  // 发送通知
}

2. Modular design

1. Single responsibility principle: Each class or method should only be responsible for one task. If a class or method takes on too many responsibilities, the code will become more complex and difficult to maintain.

// 重构前
public class OrderService {
  public void processOrder(Order order) {
    // ...
    // 订单处理逻辑代码
    // ...
    sendNotification(order);
    // ...
    // 发送通知的逻辑代码
    // ...
  }

  private void sendNotification(Order order) {
    // 发送通知的逻辑代码
  }
}

// 重构后
public class OrderService {
  public void processOrder(Order order) {
    // ...
    // 订单处理逻辑代码
    // ...
  }
}

public class NotificationService {
  public void sendNotification(Order order) {
    // 发送通知的逻辑代码
  }
}

2. Opening and closing principle: open to expansion, closed to modification. When requirements change, we should try to achieve it by extending existing modules instead of directly modifying existing code.

// 重构前
public class PaymentProcessor {
  public void processPayment(Order order) {
    // ...
    // 处理支付的逻辑代码
    // ...
    if (order.getPaymentMethod() == PaymentMethod.WECHAT) {
      // 处理微信支付的逻辑代码
    } else if (order.getPaymentMethod() == PaymentMethod.ALIPAY) {
      // 处理支付宝支付的逻辑代码
    }
  }
}

// 重构后
public interface PaymentProcessor {
  void processPayment(Order order);
}

public class WechatPaymentProcessor implements PaymentProcessor {
  @Override
  public void processPayment(Order order) {
    // 处理微信支付的逻辑代码
  }
}

public class AlipayPaymentProcessor implements PaymentProcessor {
  @Override
  public void processPayment(Order order) {
    // 处理支付宝支付的逻辑代码
  }
}

Conclusion: Code refactoring and modular design are essential links in Java development. By rationally applying code refactoring techniques and modular design principles, the maintainability and readability of the code can be improved, code redundancy and duplication can be reduced, and the code can be made clearer and easier to maintain.

Reference:

• Martin Fowler. Refactoring: Improving the Design of Existing Code. Addison-Wesley Professional, 1999.
• Robert C. Martin. Clean Architecture : A Craftsman's Guide to Software Structure and Design. Prentice Hall, 2017.

The above is the detailed content of How to perform code refactoring and modular design in Java development. For more information, please follow other related articles on the PHP Chinese website!