解决24种代码坏味道(1)

Posted on 2023-02-10 In 研发管理

1.神秘命名
如果想不出一个好的名字，说明背后很可能隐藏着更深的设计问题
看最新的《阿里开发规范1.7 黄山版》
https://developer.aliyun.com/article/888697

2.重复代码
优化：禁止复制粘贴，巧用Method Exact。
1692107737850
坏味道

/**
 * 计算水果总价（同一个类的两个函数含有相同的表达式）
 *
 */
public class FruitsCost {
    public double computeMoneyWithoutPrivileges(String type, int numbers) {
        double prices;
        switch (type) {
            case "apple":
                prices = 5.5;
                break;
            case "banana":
                prices = 4.0;
                break;
            case "strawberry":
                prices = 10.5;
                break;
            default:
                throw new IllegalArgumentException("Illegal type : " + type);
        }
        return prices * numbers;
    }

    public double computeMoneyWithPrivileges(String type, double numbers, double discount) {
        double prices;
        switch (type) {
            case "apple":
                prices = 5.5;
                break;
            case "banana":
                prices = 4.0;
                break;
            case "strawberry":
                prices = 10.5;
                break;
            default:
                throw new IllegalArgumentException("Illegal type : " + type);
        }
        return prices * numbers * discount;
    }
}

好味道

public class FruitsCost {
    public double computeMoneyWithoutPrivileges(String type, int numbers) {
        double prices = getPrices(type);
        return prices * numbers;
    }
    private double getPrices(String type) {
        double prices;
        switch (type) {
            case "apple":
                prices = 5.5;
                break;
            case "banana":
                prices = 4.0;
                break;
            case "strawberry":
                prices = 10.5;
                break;
            default:
                throw new IllegalArgumentException("Illegal type : " + type);
        }
        return prices;
    }
    public double computeMoneyWithPrivileges(String type, double numbers, double discount) {
        double prices = getPrices(type);
        return prices * numbers * discount;
    }
}

3.过长函数
优化：每个函数建议不超过80行代码，条件、循环、公共集中的过程提取处理
坏味道

public void doSth3(){
    List<String> list = new ArrayList<>();
    for(String sjs : list){
        //doSth,60行
        sjs = sjs + "";
    }
}

好味道

public void doSth3(){
    List<String> list = new ArrayList<>();
    for(String sjs : list){
        doloop(sjs);
    }
}
private static void doloop(String sjs) {
    //doSth,60行
    sjs = sjs + "";
}

4.过长参数列表
优化：使用对象合并参数
坏味道

public class Case2 {
    public void createUser(String username,String password , Float height , Float weight,Integer age){

    }
}

好味道

好味道
public class Case2 {
    public void createUser(User user){

    }
}
public class User {
    private String username
    private String password;
    //...Getter and Setter
}

5.全局数据
优化：合并数据到方法、类成员中，最小范围原则
坏味道
代码问题