java - 使用模式在 Java 中重构重复代码

Question

这更多是关于 Java 而不是 Dropwizard；但我在 Dropwizard 中有两个资源:CustomerResource 和 ApiResource。

在 CustomerResource 中有一个 createCustomer 方法，它基本上创建了一个新客户。 ApiResource 还会在第三方调用其中的方法时创建一个新客户，因此这让我开始思考重复代码和解决它的最佳方法。我有几种方法；但为了更清楚起见，这里首先是类。

@Path("/internal")        
public class CustomerResource{
    private DBDao dbDao;
    private AnotherAPI api;

    //constructor for DI

    public Response Create(@internalAuth CustomerPojo customerPojo) {
        //logic to validate customerpojo
        //logic to ensure user isn't a duplicate
        //some other validation logic
        //finally user creation/saving to DB
        Return response.ok(200).build();
    }
}

@Path("/external")
public class ApiResource{
    private DBDao dbDao;
    private AnotherAPI api;

    //constructor for DI

    public Response Create(@ExternalAuth PartialCustomerPojo partialCustomerPojo) {
        //logic to validate PartialCustomerpojo
        //supplement partialCustomerPojo
        //logic to ensure user isn't a duplicate
        //some other validation logic
        //finally user creation/saving to DB
        Return response.ok(200).build();
    }
}

因此，两个主要区别是端点的调用方式(身份验证)和提供的有效负载。

我考虑删除重复代码的方法是创建一个新的具体类，该类从两种资源中获取共性，并且每个资源都像这样实例化一个新类。

public class CommonClass{
    private DBDao dbDao;
    private AnotherAPI api;

    //constructor for DI

    public boolean Create (CommonPojo commonPojo) {
        //logic to validate customerPojo
        //logic to ensure user isn't a duplicate
        //some other validation logic
        //finally user creation/saving to DB
        Return response.ok(200).build();
    }
}

现在在 CustomerResource 和 ApiResource 中，我只是这样做。

CommonClass commonClass = new CommonClass(dbDao, api);
//create a new instance customerPojo or CommonPojo and call 

commonClass.create(customerPojo);

这听起来是个好策略吗？除了重复之外还有其他问题吗？这两个资源方法也不能在同一个类中。任何最佳实践将不胜感激。

Answer 1

我认为继承不是最好的解决方案。我也认为构图要好得多。这可以帮助您使用通用代码，并在您需要更改功能的其他地方轻松更改它。

还可以让您更轻松地测试所有类。

例如:

class CommonPojo {}
class CustomerPojo extends CommonPojo {}
class PartialCustomerPojo extends CommonPojo {}

interface IResourceValid {
    boolean isResourceValid(CommonPojo pojo);
}

class CustomerPojoValidator implements IResourceValid {
    @Override
    public boolean isResourceValid(CommonPojo pojo) {
        //your validation for customer
        return false;
    }
}

class PartialCustomerPojoValidator implements IResourceValid {
    @Override
    public boolean isResourceValid(CommonPojo pojo) {
        //your validation for partial customer
        return true;
    }
}

class CommonResource{
    private DBDao dbDao;
    private AnotherAPI api;
    private IResourceValid validator;

    public IResourceValid getValidator() {
        return validator;
    }

    //constructor for DI

    public Response Create(CommonPojo commonPojo) {
        //logic to validate customerpojo
        //logic to ensure user isn't a duplicate
        //some other validation logic
        //finally user creation/saving to DB
        validator.isResourceValid(commonPojo);
        return response.ok(200).build();
    }
}

//@Path("/internal")
class CustomerResource{
    private CommonResource resource;

    //constructor for DI

    public Response Create(CustomerPojo CustomerPojo) {
        return resource.Create(CustomerPojo);
    }
}

//@Path("/external")
class ApiResource{
    private CommonResource resource;

    //constructor for DI

    public Response Create(PartialCustomerPojo partialCustomerPojo) {
        return resource.Create(partialCustomerPojo);
    }
}

DBDao dao = new DBDao();
AnotherAPI api = new AnotherAPI();

CommonResource castomerCreator = new CommonResource(new CustomerPojoValidator(), dao, api);
CommonResource apiCreator = new CommonResource(new PartialCustomerPojoValidator(), dao, api);

CustomerResource customerResource = new CustomerResource(castomerCreator);
ApiResource apiResource = new ApiResource(apiCreator);

customerResource.Create(somePojo);
apiResource.Create(someAnotherPojo);