從普通到優秀！Java 資深開發者是如何審查代碼的？

作者：路條編程 2025-04-28 08:18:25

在這篇文章中，我們將一起進行幾次代碼審查，同時學習在審查時需要關注哪些問題。還會討論如何以專業且尊重的態度參與代碼審查。

在這篇文章中，我們將一起進行幾次代碼審查，同時學習在審查時需要關注哪些問題。還會討論如何以專業且尊重的態度參與代碼審查。

話不多說，讓我們開始吧！

審查1：發現常見錯誤

在審查任何代碼時，我首先關注有沒有一些常見但容易被忽視的錯誤。

來看下面這段代碼，找找其中的問題：

package com.icoderoad.order;


import java.util.List;


public class OrderProcessor {


    private final List<Order> orders;


    public OrderProcessor(List<Order> orders) {
        this.orders = orders;
    }


    public void processOrders() {
        for (Order order : orders) {
            if ("Paid".equals(order.getOrderStatus())) {
                order.setOrderStatus("Shipped");
                System.out.println("Order " + order.getOrderId() + " is now Shipped.");
            } else if ("Shipped".equals(order.getOrderStatus())) {
                order.setOrderStatus("Completed");
                System.out.println("Order " + order.getOrderId() + " is now Completed.");
            }
        }
    }
}


class Order {
    private int orderId;
    private String orderStatus;
    private double totalAmount;


    // getters and setters
}

你發現什么問題了嗎？沒錯！這段代碼存在：

缺少異常處理（沒有 try-catch）
硬編碼字符串（"Paid"、"Shipped"）
命名風格不統一（orderId vs orderStatus vs totalAmount）

修正后的版本：

package com.icoderoad.order;


import java.util.List;


public class OrderProcessor {


    private final List<Order> orders;


    public OrderProcessor(List<Order> orders) {
        this.orders = orders;
    }


    public void processOrders() {
        for (Order order : orders) {
            try {
                switch (order.getStatus()) {
                    case PAID -> {
                        order.setStatus(OrderStatus.SHIPPED);
                        System.out.println("Order " + order.getId() + " is now Shipped.");
                    }
                    case SHIPPED -> {
                        order.setStatus(OrderStatus.COMPLETED);
                        System.out.println("Order " + order.getId() + " is now Completed.");
                    }
                    default -> System.out.println("Order " + order.getId() + " has an unknown status: " + order.getStatus());
                }
            } catch (Exception ex) {
                System.err.println("Error processing order " + order.getId() + ": " + ex.getMessage());
            }
        }
    }
}
package com.icoderoad.order;


public class Order {


    private int id;
    private OrderStatus status;
    private double totalAmount;


    // getters and setters
}
package com.icoderoad.order;


public enum OrderStatus {
    PAID,
    SHIPPED,
    COMPLETED
}

審查2：遺漏空值檢查（Null Check）

再來看這段：

package com.icoderoad.customer;


import java.util.List;


public class OrderProcessor {


    public void getCustomerOrderDetails(Customer customer) {
        if (customer.getOrders().size() > 0) {
            for (Order order : customer.getOrders()) {
                System.out.println("Order ID: " + order.getId() + ", Amount: " + order.getAmount());
            }
        } else {
            System.out.println("No orders found.");
        }
    }
}

發現問題了嗎？正確！這里缺少空值檢查，如果 customer 或 orders 為 null，就直接崩潰了！

修正后的版本：

package com.icoderoad.customer;


import java.util.List;


public class OrderProcessor {


    public void getCustomerOrderDetails(Customer customer) {
        if (customer == null) {
            System.out.println("Customer is null.");
            return;
        }


        List<Order> orders = customer.getOrders();
        if (orders == null || orders.isEmpty()) {
            System.out.println("No orders found.");
            return;
        }


        for (Order order : orders) {
            System.out.println("Order ID: " + order.getId() + ", Amount: " + order.getAmount());
        }
    }
}

審查3：強耦合（Tight Coupling）

繼續看：

package com.icoderoad.order;


public class OrderService {


    private final PaymentService paymentService = new PaymentService();


    public void processOrder(Order order) {
        paymentService.processPayment(order);
    }
}

沒錯，這是強耦合設計！OrderService 直接綁定了具體實現，難以測試和擴展。

更好的方式：使用接口 + 構造器注入（Dependency Injection）

package com.icoderoad.order;


public class OrderService {


    private final IPaymentService paymentService;


    public OrderService(IPaymentService paymentService) {
        this.paymentService = paymentService;
    }


    public void processOrder(Order order) {
        paymentService.processPayment(order);
    }
}

審查4：神秘數字（Magic Numbers）

你的朋友寫了稅率邏輯：

package com.icoderoad.tax;


public class TaxCalculator {


    public double calculateTax(double income) {
        if (income <= 50000) return income * 0.10;
        if (income <= 100000) return income * 0.15;
        if (income <= 200000) return income * 0.20;
        return income * 0.30;
    }
}

這里有大量魔法數字，后期改動會非常痛苦。

更好的設計：

package com.icoderoad.tax;


import java.util.List;


public class TaxCalculator {


    private final List<Double> incomeSlabs;
    private final List<Double> taxRates;


    public TaxCalculator(List<Double> incomeSlabs, List<Double> taxRates) {
        this.incomeSlabs = incomeSlabs;
        this.taxRates = taxRates;
    }


    public double calculateTax(double income) {
        for (int i = 0; i < incomeSlabs.size(); i++) {
            if (income <= incomeSlabs.get(i)) {
                return income * taxRates.get(i);
            }
        }
        return income * taxRates.get(taxRates.size() - 1);
    }
}

配合配置文件或常量管理，維護性更高！

審查5：別重復你自己（DRY）

看下面的代碼：

package com.icoderoad.discount;


public class DiscountCalculator {


    public double calculateDiscount(double amount, double discountPercentage) {
        double discount = amount * discountPercentage;
        return amount - discount;
    }


    public double applyDiscount(double amount, double discountPercentage) {
        double discount = amount * discountPercentage;
        return amount - discount;
    }
}

這里明顯重復了邏輯！

正確版本：

package com.icoderoad.discount;


public class DiscountCalculator {


    public double calculateDiscount(double amount, double discountPercentage) {
        return applyDiscount(amount, discountPercentage);
    }


    public double applyDiscount(double amount, double discountPercentage) {
        return amount - calculateDiscountAmount(amount, discountPercentage);
    }


    private double calculateDiscountAmount(double amount, double discountPercentage) {
        return amount * discountPercentage;
    }
}

審查6：YAGNI原則（You Aren’t Gonna Need It）

最后，來看這段帶優惠券處理的代碼：

package com.icoderoad.order;


public class OrderProcessor {


    public void processOrder(Order order, double discount) {
        double discountAmount = order.getAmount() * discount;
        double finalAmount = order.getAmount() - discountAmount;


        System.out.println("Discount Applied: " + discountAmount);


        if (order.getCouponCode() != null) {
            double couponDiscount = applyCoupon(order.getCouponDiscount());
            finalAmount -= couponDiscount;
            System.out.println("Coupon " + order.getCouponCode() + " applied.");
        }
    }


    private double applyCoupon(double couponDiscount) {
        return couponDiscount;
    }
}

問題在于：需求只要做折扣，卻提前加了優惠券邏輯，增加了不必要復雜性！

遵循 YAGNI 原則：只做需求中需要的內容。

精簡版：

package com.icoderoad.order;


public class OrderProcessor {


    public void processOrder(Order order, double discount) {
        double discountAmount = order.getAmount() * discount;
        double finalAmount = order.getAmount() - discountAmount;
        System.out.println("Discount Applied: " + discountAmount);
    }
}

總結

一個優秀的 Java 開發者，在代碼審查時應該特別關注：

是否有異常處理和日志
命名風格是否統一
是否避免了魔法數字
是否做了空值檢查
是否違反 DRY 原則
是否提前開發了無關功能（YAGNI）
是否有合理的接口隔離和依賴注入設計

審代碼，不止是挑刺，更是讓團隊代碼整體更健康、更易維護！

責任編輯：武曉燕來源：路條編程

代碼遺漏空值強耦合

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