一、需求开发修正代码

一次需求开发时碰到如下所示办法代码：

private OrderShoudSettlementAmount getOrderShoudSettlementAmount(OrderDTO orderMain, List<SettlementDetail> details) {
    OrderShoudSettlementAmount settlementAmount = new OrderShoudSettlementAmount();
    // 应结金额=33021-33002-32003+32001-31001
    // 货款佣钱=33005+33002+32003+31001
    long feeMoney33021 = 0;
    long feeMoney33002 = 0;
    long feeMoney32003 = 0;
    long feeMoney32001 = 0;
    long feeMoney31001 = 0;
    long feeMoney33005 = 0;
    for (SettlementDetail settlementDetail : details) {
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_FREIGHT_ZS_NOSETTLE.getVal())) {
            feeMoney33021 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_FREIGHT_YJ_ZS_NOSETTLE.getVal())) {
            feeMoney33002 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_GOODS_YJ_WJTZ.getVal())) {
            feeMoney32003 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_GOODS_NOSETTLE.getVal())) {
            feeMoney32001 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_BDYJ_YJ_NOSETTLE.getVal())) {
            feeMoney31001 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_YFYJ_ZS_XSG.getVal())) {
            feeMoney33005 += settlementDetail.getOassMoney();
        }
    }
    long settlementMoney = feeMoney33021 - feeMoney33002 - feeMoney32003 + feeMoney32001 - feeMoney31001;
    long goodCommissionMoney = feeMoney33005 + feeMoney33002 + feeMoney32003 + feeMoney31001;
    settlementAmount.setSettlementAmount(settlementMoney);
    settlementAmount.setGoodsCommission(goodCommissionMoney);
    settlementAmount.setOrderId(orderMain.getOrderId());
    settlementAmount.setOrgCode(orderMain.getOrgCode());
    settlementAmount.setStationNo(String.valueOf(orderMain.getDeliveryStationNo()));
    settlementAmount.setBillTime(new Date());
    settlementAmount.setRetSuccess(false);
    return settlementAmount;
}

该办法逻辑比较简略，就是拼装OrderShoudSettlementAmount目标。其间需求核算2个金额，分别是settlementMoney和goodCommissionMoney。

本次需求新增了费项，需求修正该办法。代码修正后如下所示：

private OrderShoudSettlementAmount getOrderShoudSettlementAmount(OrderDTO orderMain, List<SettlementDetail> details) {
    OrderShoudSettlementAmount settlementAmount = new OrderShoudSettlementAmount();
    // 应结金额=33021-33002-32003+32001-31001+34012-34013
    // 货款佣钱=33005+33002+32003+31001+34013
    long feeMoney33021 = 0;
    long feeMoney33002 = 0;
    long feeMoney32003 = 0;
    long feeMoney32001 = 0;
    long feeMoney31001 = 0;
    long feeMoney33005 = 0;
    // 本次需求新增费项
    long feeMoney34012 = 0;
    // 本次需求新增费项
    long feeMoney34013 = 0;
    for (SettlementDetail settlementDetail : details) {
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_FREIGHT_ZS_NOSETTLE.getVal())) {
            feeMoney33021 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_FREIGHT_YJ_ZS_NOSETTLE.getVal())) {
            feeMoney33002 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_GOODS_YJ_WJTZ.getVal())) {
            feeMoney32003 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_GOODS_NOSETTLE.getVal())) {
            feeMoney32001 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_BDYJ_YJ_NOSETTLE.getVal())) {
            feeMoney31001 += settlementDetail.getOassMoney();
        }
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_YFYJ_ZS_XSG.getVal())) {
            feeMoney33005 += settlementDetail.getOassMoney();
        }
        // 本次需求新增费项
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_CHF_XSG_NOSETTLE.getVal())) {
            feeMoney34012 += settlementDetail.getOassMoney();
        }
        // 本次需求新增费项
        if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_CHF_YJ_XSG.getVal())) {
            feeMoney34013 += settlementDetail.getOassMoney();
        }
    }
    // 本次需求新增费项追加核算 + feeMoney34012 - feeMoney34013
    long settlementMoney = feeMoney33021 - feeMoney33002 - feeMoney32003 + feeMoney32001 - feeMoney31001 + feeMoney34012 - feeMoney34013;
    // 本次需求新增费项追加核算 + feeMoney34013
    long goodCommissionMoney = feeMoney33005 + feeMoney33002 + feeMoney32003 + feeMoney31001 + feeMoney34013;
    settlementAmount.setSettlementAmount(settlementMoney);
    settlementAmount.setGoodsCommission(goodCommissionMoney);
    settlementAmount.setOrderId(orderMain.getOrderId());
    settlementAmount.setOrgCode(orderMain.getOrgCode());
    settlementAmount.setStationNo(String.valueOf(orderMain.getDeliveryStationNo()));
    settlementAmount.setBillTime(new Date());
    settlementAmount.setRetSuccess(false);
    return settlementAmount;
}

二、嗅出代码的坏滋味

Martin Fowler在《重构：改进既有代码的规划》一书中列出了22种代码的坏滋味：

1.Duplicated Code（重复的代码） 2.Long Method（过长函数） 3.Large Class（过大类） 4.Long Parameter List（过长参数列） 5.Divergent Change（发散式改变） 6.Shotgun Surgery（霰弹式修正） 7.Feature Envy（依恋情结） 8.Data Clumps（数据泥团） 9.Primitive Obsession（基本型别偏执） 10.Switch Statements（switch惊悚现身） 11.Parallel Inheritance Hierarchies（平行承继系统） 12.Lazy Class（冗赘类） 13.Speculative Generality（纸上谈兵未来性） 14.Temporary Field（令人利诱的暂时字段） 15.Message Chains（过度耦合的消息链） 16.Middle Man（中间人） 17.Inappropriate Intimacy（狎昵关系） 18.Alternative Classes with Different Interfaces（异曲同工的类） 19.Incomplete Library Class（不完美的程序库类） 20.Data Class（纯稚的数据类） 21.Refused Bequest（被回绝的遗贈） 22.Comments（过多的注释）

参照这22种代码的坏滋味，我在以上办法代码中嗅出了2种代码的坏滋味：

坏滋味1：Duplicated Code（重复的代码）

for循环中对每种费项的累加操作是重复代码，并且每次新增费项，还得不断增加该重复操作。

for (SettlementDetail settlementDetail : details) {
    if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_FREIGHT_ZS_NOSETTLE.getVal())) {
        feeMoney33021 += settlementDetail.getOassMoney();
    }
    if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_FREIGHT_YJ_ZS_NOSETTLE.getVal())) {
        feeMoney33002 += settlementDetail.getOassMoney();
    }
    if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_GOODS_YJ_WJTZ.getVal())) {
        feeMoney32003 += settlementDetail.getOassMoney();
    }
    if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_GOODS_NOSETTLE.getVal())) {
        feeMoney32001 += settlementDetail.getOassMoney();
    }
    if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_BDYJ_YJ_NOSETTLE.getVal())) {
        feeMoney31001 += settlementDetail.getOassMoney();
    }
    if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_YFYJ_ZS_XSG.getVal())) {
        feeMoney33005 += settlementDetail.getOassMoney();
    }
    // 本次需求新增费项
    if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_CHF_XSG_NOSETTLE.getVal())) {
        feeMoney34012 += settlementDetail.getOassMoney();
    }
    // 本次需求新增费项
    if (settlementDetail.getExpenseType().equals(FeeInfoEnum.FEE_INFO_CHF_YJ_XSG.getVal())) {
        feeMoney34013 += settlementDetail.getOassMoney();
    }
}

坏滋味2：Divergent Change（发散式改变）

Martin Fowler在书中对该坏滋味的部分解说如下：

咱们期望软件可以更容易被修正——究竟软件再怎么说本来就该是“软”的。一旦需求修正，咱们期望可以跳到系统的某一点，只在该处做修正。

现在该办法代码因为新需求开发，修正多处。

其实，除了以上2种代码的坏滋味之外，该办法代码最大的问题是面向过程式编码而不是面向目标式的。

为什么这么说呢？

前面提到过该办法的首要作用是拼装OrderShoudSettlementAmount目标，那么其逻辑就应该首要体现“拼装”，而不是核算金额。核算金额相关逻辑应该抽离到单独的类中，这样既契合面向目标编程思维，也可以消除坏滋味2。

三、重构代码

针对前面嗅出的代码坏滋味，果断进行重构。重构之后代码如下所示：

private OrderShoudSettlementAmount getOrderShoudSettlementAmount(OrderDTO orderMain, List<SettlementDetail> details) {
    OrderShoudSettlementAmount settlementAmount = new OrderShoudSettlementAmount();
    Map<Integer, Long> expenseTypeToFeeMoneyMap = Maps.newHashMap();
    for (SettlementDetail settlementDetail : details) {
        long feeMoney = Optional.ofNullable(expenseTypeToFeeMoneyMap.get(settlementDetail.getExpenseType())).orElse(0L);
        feeMoney += Optional.ofNullable(settlementDetail.getOassMoney()).orElse(0L);
        expenseTypeToFeeMoneyMap.put(settlementDetail.getExpenseType(), feeMoney);
    }
    long settlementMoney = SettlementMoneyCalcFeeInfoEnum.calcSettlementMoney(expenseTypeToFeeMoneyMap);
    long goodCommissionMoney = GoodCommissionMoneyCalcFeeInfoEnum.calcGoodCommissionMoney(expenseTypeToFeeMoneyMap);
    settlementAmount.setSettlementAmount(settlementMoney);
    settlementAmount.setGoodsCommission(goodCommissionMoney);
    settlementAmount.setOrderId(orderMain.getOrderId());
    settlementAmount.setOrgCode(orderMain.getOrgCode());
    settlementAmount.setStationNo(String.valueOf(orderMain.getDeliveryStationNo()));
    settlementAmount.setBillTime(new Date());
    settlementAmount.setRetSuccess(false);
    return settlementAmount;
}

enum SettlementMoneyCalcFeeInfoEnum {
    /**核算项*/
    FEE_33021(FeeInfoEnum.FEE_INFO_FREIGHT_ZS_NOSETTLE, "+"),
    FEE_33002(FeeInfoEnum.FEE_INFO_FREIGHT_YJ_ZS_NOSETTLE, "-"),
    FEE_32003(FeeInfoEnum.FEE_INFO_GOODS_YJ_WJTZ, "-"),
    FEE_32001(FeeInfoEnum.FEE_INFO_GOODS_NOSETTLE, "+"),
    FEE_31001(FeeInfoEnum.FEE_INFO_BDYJ_YJ_NOSETTLE, "-"),
    FEE_34012(FeeInfoEnum.FEE_INFO_CHF_XSG_NOSETTLE, "+"),
    FEE_34013(FeeInfoEnum.FEE_INFO_CHF_YJ_XSG, "-");
    private final FeeInfoEnum feeInfoEnum;
    private final String symbol;
    SettlementMoneyCalcFeeInfoEnum(FeeInfoEnum feeInfoEnum, String symbol) {
        this.feeInfoEnum = feeInfoEnum;
        this.symbol = symbol;
    }
    public static long calcSettlementMoney(Map<Integer, Long> expenseTypeToFeeMoneyMap) {
        // 应结金额=33021-33002-32003+32001-31001+34012-34013
        long settlementMoney = 0L;
        for (SettlementMoneyCalcFeeInfoEnum calcFeeInfoEnum : SettlementMoneyCalcFeeInfoEnum.values()) {
            if ("+".equals(calcFeeInfoEnum.symbol)) {
                settlementMoney += Optional
                        .ofNullable(expenseTypeToFeeMoneyMap.get(calcFeeInfoEnum.feeInfoEnum.getVal()))
                        .orElse(0L);
            }
            if ("-".equals(calcFeeInfoEnum.symbol)) {
                settlementMoney -= Optional
                        .ofNullable(expenseTypeToFeeMoneyMap.get(calcFeeInfoEnum.feeInfoEnum.getVal()))
                        .orElse(0L);
            }
        }
        return settlementMoney;
    }
}

enum GoodCommissionMoneyCalcFeeInfoEnum {
    /**核算项*/
    FEE_33005(FeeInfoEnum.FEE_INFO_YFYJ_ZS_XSG),
    FEE_33002(FeeInfoEnum.FEE_INFO_FREIGHT_YJ_ZS_NOSETTLE),
    FEE_32003(FeeInfoEnum.FEE_INFO_GOODS_YJ_WJTZ),
    FEE_31001(FeeInfoEnum.FEE_INFO_BDYJ_YJ_NOSETTLE),
    FEE_34013(FeeInfoEnum.FEE_INFO_CHF_YJ_XSG);
    private final FeeInfoEnum feeInfoEnum;
    GoodCommissionMoneyCalcFeeInfoEnum(FeeInfoEnum feeInfoEnum) {
        this.feeInfoEnum = feeInfoEnum;
    }
    public static long calcGoodCommissionMoney(Map<Integer, Long> expenseTypeToFeeMoneyMap) {
        // 货款佣钱=33005+33002+32003+31001+34013
        long goodCommissionMoney = 0L;
        for (GoodCommissionMoneyCalcFeeInfoEnum calcFeeInfoEnum : GoodCommissionMoneyCalcFeeInfoEnum.values()) {
            goodCommissionMoney += Optional
                    .ofNullable(expenseTypeToFeeMoneyMap.get(calcFeeInfoEnum.feeInfoEnum.getVal()))
                    .orElse(0L);
        }
        return goodCommissionMoney;
    }
}

四、总结

以上重构的办法代码比较简略，有些人可能会觉得不重构也挺好的，代码可读性也不差，每次修正也就肉眼可见的几个当地，没必要在这上面花费时间。

假如你有以上想法，无妨了解下软件工程中的“破窗效应”：

破窗效应指的是在软件开发过程中，假如存在低质量的代码或规划，假如不及时修复，就会导致其他开发人员也选用同样的低质量计划。这会逐步升级到更严重的问题，导致软件系统变得难以维护、扩展和改进。因此，在软件开发中，及时解决问题和保持代码质量非常重要，以防止破窗效应关于整个项目造成的负面影响。

一起看看Martin Fowler在《重构：改进既有代码的规划》一书中对重构的部分解说：

重构的每个步骤都很简略，乃至显得有些过于简略：你只需求把某个字段从一个类移到另一个类，把某些代码从一个函数拉出来构成另一个函数，或是在承继系统中把某些代码推上推下就行了。但是，聚沙成塔，这些小小的修正累积起来就可以根本改进规划质量。

重构不只可以提高代码质量，让代码高雅起来，一起也能让咱们学以致用。咱们所学的规划思维、准则、形式等理论知识，往往在重构中可以真正实践。

作者：京东零售加文雄

来历：京东云开发者社区

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让代码优雅起来：记一次代码微重构实践 | 京东云技术团队

一、需求开发修正代码

二、嗅出代码的坏滋味

三、重构代码

四、总结

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