如何避免过多if语句？求重构该Java方法的可行方案

原方法包含大量分散的if判断，维护性差，拆分布尔方法也无法减少if数量，以下是可行的重构方案：

原方法代码 #

private String getFolderValue(TableRow row) {
    String cote = row.getCellValue("B");
    String typologie = row.getCellValue("G");
    String description = row.getCellValue("Q");
    if (cote.startsWith("DE")) {
        return "Dessins";
    }
    if (cote.startsWith("PH")){
        return "Photographies";
    }
    if(cote.startsWith("CA")) {
        return "Catalogues";
    }
    if(cote.startsWith("PU") && typologie.contains("affiche")){
        return "Publicité###Affiches";
    }

    if(cote.startsWith("PU") && typologie.contains("flyer")){
        return "Publicité###Flyers";
    }

    if(cote.startsWith("PU") && description.contains("presse")){
        return "Publicité###Presse";
    }

    if(cote.startsWith("PU") && (description.contains("Facture") || description.contains("devis"))){
        return "Documents###Vente";
    }

    if(typologie.contains("Emballage")){
        return "Visual Merchandising###Flyers";
    }

    if(typologie.contains("PLV")){
        return "Visual Merchandising###PLV";
    }
    if(description.contains("Correspondances")){
        return "Documents###Correspondances";
    }

    return null;
}

重构方案：规则匹配模式 #

核心思路是将每个判断逻辑封装为独立的规则单元，通过遍历规则列表找到匹配项，彻底消除冗余if，同时提升扩展性。

步骤1：定义规则接口 #

创建统一的规则接口，包含匹配逻辑和结果获取方法：

interface FolderRule {
    boolean matches(String cote, String typologie, String description);
    String getFolderPath();
}

步骤2：初始化规则列表 #

将原方法中的每个if判断转换为规则实例，存入列表（Java 8+可使用lambda简化定义）：

private static final List<FolderRule> FOLDER_RULES = Arrays.asList(
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return c.startsWith("DE");
        }
        @Override
        public String getFolderPath() {
            return "Dessins";
        }
    },
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return c.startsWith("PH");
        }
        @Override
        public String getFolderPath() {
            return "Photographies";
        }
    },
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return c.startsWith("CA");
        }
        @Override
        public String getFolderPath() {
            return "Catalogues";
        }
    },
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return c.startsWith("PU") && t.contains("affiche");
        }
        @Override
        public String getFolderPath() {
            return "Publicité###Affiches";
        }
    },
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return c.startsWith("PU") && t.contains("flyer");
        }
        @Override
        public String getFolderPath() {
            return "Publicité###Flyers";
        }
    },
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return c.startsWith("PU") && d.contains("presse");
        }
        @Override
        public String getFolderPath() {
            return "Publicité###Presse";
        }
    },
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return c.startsWith("PU") && (d.contains("Facture") || d.contains("devis"));
        }
        @Override
        public String getFolderPath() {
            return "Documents###Vente";
        }
    },
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return t.contains("Emballage");
        }
        @Override
        public String getFolderPath() {
            return "Visual Merchandising###Flyers";
        }
    },
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return t.contains("PLV");
        }
        @Override
        public String getFolderPath() {
            return "Visual Merchandising###PLV";
        }
    },
    new FolderRule() {
        @Override
        public boolean matches(String c, String t, String d) {
            return d.contains("Correspondances");
        }
        @Override
        public String getFolderPath() {
            return "Documents###Correspondances";
        }
    }
);

步骤3：简化原方法 #

遍历规则列表，返回第一个匹配的结果：

private String getFolderValue(TableRow row) {
    String cote = row.getCellValue("B");
    String typologie = row.getCellValue("G");
    String description = row.getCellValue("Q");

    for (FolderRule rule : FOLDER_RULES) {
        if (rule.matches(cote, typologie, description)) {
            return rule.getFolderPath();
        }
    }
    return null;
}

进阶优化（Java 16+） #

使用**记录类(Record)**进一步简化规则定义，减少冗余代码：

// 定义上下文记录类，封装三个参数
record RuleContext(String cote, String typologie, String description) {}

// 定义通用规则记录类
record SimpleFolderRule(Predicate<RuleContext> matcher, String folderPath) implements FolderRule {
    @Override
    public boolean matches(String cote, String typologie, String description) {
        return matcher.test(new RuleContext(cote, typologie, description));
    }

    @Override
    public String getFolderPath() {
        return folderPath;
    }
}

// 规则列表可简化为：
private static final List<FolderRule> FOLDER_RULES = Arrays.asList(
    new SimpleFolderRule(ctx -> ctx.cote().startsWith("DE"), "Dessins"),
    new SimpleFolderRule(ctx -> ctx.cote().startsWith("PH"), "Photographies"),
    new SimpleFolderRule(ctx -> ctx.cote().startsWith("CA"), "Catalogues"),
    new SimpleFolderRule(ctx -> ctx.cote().startsWith("PU") && ctx.typologie().contains("affiche"), "Publicité###Affiches"),
    new SimpleFolderRule(ctx -> ctx.cote().startsWith("PU") && ctx.typologie().contains("flyer"), "Publicité###Flyers"),
    new SimpleFolderRule(ctx -> ctx.cote().startsWith("PU") && ctx.description().contains("presse"), "Publicité###Presse"),
    new SimpleFolderRule(ctx -> ctx.cote().startsWith("PU") && (ctx.description().contains("Facture") || ctx.description().contains("devis")), "Documents###Vente"),
    new SimpleFolderRule(ctx -> ctx.typologie().contains("Emballage"), "Visual Merchandising###Flyers"),
    new SimpleFolderRule(ctx -> ctx.typologie().contains("PLV"), "Visual Merchandising###PLV"),
    new SimpleFolderRule(ctx -> ctx.description().contains("Correspondances"), "Documents###Correspondances")
);

重构优势 #

• 彻底消除大量if语句，代码结构更清晰
• 新增规则只需在列表中添加实例，符合开闭原则
• 每个规则逻辑独立，便于单独测试和维护

内容的提问来源于stack exchange，提问作者JhinKazama