Claude Code 眼中的"优秀 Java 代码"只有5条规则

// 示例代码
public String getOrderStatus(Long orderId, String userId) {
    return orderId != null ? (userId != null ?
        orderService.findOrder(orderId, userId).getStatus() : "用户ID为空") : "订单ID为空";
}

// 示例代码
public String getOrderStatus(Long orderId, String userId) {
    if (orderId == null) return "订单ID为空";
    if (userId == null) return "用户ID为空";
    return orderService.findOrder(orderId, userId).getStatus();
}

// 示例代码 - 原始版本
public boolean validateCoupon(String couponCode, BigDecimal orderAmount) {
    Coupon coupon = couponService.findByCode(couponCode);
    if (coupon == null) return false;
    if (coupon.isExpired()) return false;
    if (orderAmount.compareTo(coupon.getMinAmount()) < 0) return false;
    return true;
}

// 示例代码 - 优化版本
public boolean validateCoupon(String couponCode, BigDecimal orderAmount) {
    Coupon coupon = couponService.findByCode(couponCode);
    if (coupon == null || coupon.isExpired()) return false;
    return orderAmount.compareTo(coupon.getMinAmount()) >= 0;
}

// 示例代码 - 过度优化，改变了逻辑
public boolean validateCoupon(String couponCode, BigDecimal orderAmount) {
    return Optional.ofNullable(couponService.findByCode(couponCode))
        .filter(c -> !c.isExpired() && orderAmount.compareTo(c.getMinAmount()) >= 0)
        .isPresent();
}

// 示例代码
// 原始版本 - 紧凑但难懂
public String calculateOrderStatus(PigOrder order) {
    return order.isPaid() ? (order.isShipped() ? (order.isDelivered() ? "已完成" : "配送中") : "待发货") : "待支付";
}

// 示例代码
// 优化版本 - 清晰易懂
public String calculateOrderStatus(PigOrder order) {
    if (!order.isPaid()) return "待支付";
    if (!order.isShipped()) return "待发货";
    if (!order.isDelivered()) return "配送中";
    return "已完成";
}

// 示例代码
// 原始版本 - 过度紧凑
public int calculatePoints(PigOrder order) {
    return (int) (order.getAmount().doubleValue() *
        (order.isVip() ? 1.5 : 1.0) *
        (order.hasUsedCoupon() ? 0.8 : 1.0));
}

// 示例代码
// 优化版本 - 显式表达
public int calculatePoints(PigOrder order) {
    double basePoints = order.getAmount().doubleValue();
    double vipMultiplier = order.isVip() ? 1.5 : 1.0;
    double couponPenalty = order.hasUsedCoupon() ? 0.8 : 1.0;

    return (int) (basePoints * vipMultiplier * couponPenalty);
}

// 示例代码
// 原始版本 - 使用 Lambda
private Function<List<PigOrder>, List<PigOrder>> filterActiveOrders =
    orders -> orders.stream()
        .filter(order -> !order.isCancelled())
        .collect(Collectors.toList());

// 示例代码
// 优化版本 - 普通方法，符合项目标准
public List<PigOrder> filterActiveOrders(List<PigOrder> orders) {
    return orders.stream()
        .filter(order -> !order.isCancelled())
        .collect(Collectors.toList());
}

// 示例代码
// 原始版本 - 有适当的抽象
public class PigOrderService {

    public PigOrder createOrder(OrderRequest request) {
        validateRequest(request);
        PigOrder order = buildOrder(request);
        applyDiscounts(order, request);
        saveOrder(order);
        sendConfirmation(order);
        return order;
    }

    private void validateRequest(OrderRequest request) {
        if (request.getUserId() == null) throw new IllegalArgumentException("用户ID不能为空");
        if (request.getItems().isEmpty()) throw new IllegalArgumentException("订单项不能为空");
    }

    private PigOrder buildOrder(OrderRequest request) {
        // 构建订单的逻辑
    }

    private void applyDiscounts(PigOrder order, OrderRequest request) {
        // 应用折扣的逻辑
    }

    // ... 其他方法
}

// 示例代码
// 过度简化版本
public class PigOrderService {

    public PigOrder createOrder(OrderRequest request) {
        if (request.getUserId() == null || request.getItems().isEmpty()) {
            throw new IllegalArgumentException("请求无效");
        }

        PigOrder order = new PigOrder();
        // 所有逻辑都塞在这里...

        return order;
    }
}

// 示例代码
// 优化前：冗长的代码
public ProcessResult processUserData(UserData userData, Options options) {
    ProcessResult result = new ProcessResult();
    result.setProcessed(false);
    result.setData(null);
    result.setErrors(new ArrayList<>());

    if (userData != null && userData.getId() != null && userData.getEmail() != null) {
        try {
            ProcessedData processedData = new ProcessedData();
            processedData.setId(userData.getId());
            processedData.setEmail(userData.getEmail().toLowerCase().trim());
            processedData.setTimestamp(System.currentTimeMillis());
            result.setData(processedData);
            result.setProcessed(true);
        } catch (Exception e) {
            result.getErrors().add(e.getMessage());
        }
    }
    return result;
}

// 优化后：简洁的代码（token 减少约 28%）
public ProcessResult processUserData(UserData userData, Options options) {
    if (userData == null || userData.getId() == null || userData.getEmail() == null) {
        return new ProcessResult(false, null, new ArrayList<>());
    }

    ProcessedData data = new ProcessedData(
        userData.getId(),
        userData.getEmail().toLowerCase().trim(),
        System.currentTimeMillis()
    );

    return new ProcessResult(true, data, new ArrayList<>());
}