Question

因此，我在Java项目的Application（Main）类的main方法中要执行很多行代码。为了摆脱所有混乱，我最终使用了extract方法重构技术对其进行了重构，但是随后在Main类中得到了很多静态方法，因此我不喜欢....哪一种更好呢？干净的主要应用方法的方法？我应该使用单例类吗？应该使用什么其他设计模式/技术来避免在我的主类中包含所有这些静态方法，并使主方法尽可能简洁？

初始代码：

import controller.Statistics;
import model.primary.customer.CustomerInfo;
import model.primary.movie.MovieInfo;
import model.primary.rating.RatingInfo;
import util.FileParsing.FileParser;
import util.mapping.CustomerMapper;
import util.mapping.MovieMapper;
import util.mapping.RatingsMapper;
import view.DisplayStatistics;
import view.UserInterface;

public class Application {

    public static void main(String[] args) {
        Statistics statistics = processStatistics();
        DisplayStatistics displayStatistics = new DisplayStatistics(statistics);
        initiateUI(displayStatistics);
    }

    private static Statistics processStatistics() {
        MovieInfo movieInfo = processMovies();
        CustomerInfo customerInfo = processCustomers();
        RatingInfo ratingInfo = processRatings();

        return new Statistics(customerInfo, movieInfo, ratingInfo);
    }

    private static void initiateUI(DisplayStatistics displayStatistics) {
        UserInterface userInterface = new UserInterface(displayStatistics);
        userInterface.start();
    }

    private static RatingInfo processRatings() {
        FileParser ratingsFile = new FileParser("ratings.dat", "::");
        RatingsMapper ratingsMapper = new RatingsMapper(ratingsFile, 4);
        return new RatingInfo(ratingsMapper.getCustomerIDMovieIDRatingAndTimeMap());
    }

    private static CustomerInfo processCustomers() {
        FileParser customerFile = new FileParser("users.dat", "::");
        CustomerMapper customerMapper = new CustomerMapper(customerFile, 5);
        return new CustomerInfo(customerMapper.getIdCustomerMap());
    }

    private static MovieInfo processMovies() {
        FileParser movieFile = new FileParser("movies.dat", "::");
        MovieMapper movieMapper = new MovieMapper(movieFile, 3);
        return new MovieInfo(movieMapper.getIdMovieMap());
    }

}

在使用Singleton类（处理器）之后更改了代码：

import controller.Statistics;
import view.DisplayStatistics;
import view.UserInterface;

public class Application {

    public static void main(String[] args) {

        Statistics statistics = Processor.getInstance().processStatistics();

        DisplayStatistics displayStatistics = new DisplayStatistics(statistics);

        UserInterface userInterface = new UserInterface(displayStatistics);

        userInterface.start();
    }


}

单类（处理器）代码：

import controller.Statistics;
import model.primary.customer.CustomerInfo;
import model.primary.movie.MovieInfo;
import model.primary.rating.RatingInfo;
import util.FileParsing.FileParser;
import util.mapping.CustomerMapper;
import util.mapping.MovieMapper;
import util.mapping.RatingsMapper;


public class Processor {
    private static Processor ourInstance = new Processor();

    public static Processor getInstance() {
        return ourInstance;
    }

    private Processor() {

    }

    static Statistics processStatistics() {

        MovieInfo movieInfo = processMovies();
        CustomerInfo customerInfo = processCustomers();
        RatingInfo ratingInfo = processRatings();

        return new Statistics(customerInfo, movieInfo, ratingInfo);
    }

    private static RatingInfo processRatings() {

        FileParser ratingsFile = new FileParser("ratings.dat", "::");
        RatingsMapper ratingsMapper = new RatingsMapper(ratingsFile, 4);
        return new RatingInfo(ratingsMapper.getCustomerIDMovieIDRatingAndTimeMap());
    }

    private static CustomerInfo processCustomers() {

        FileParser customerFile = new FileParser("users.dat", "::");
        CustomerMapper customerMapper = new CustomerMapper(customerFile, 5);
        return new CustomerInfo(customerMapper.getIdCustomerMap());
    }

    private static MovieInfo processMovies() {

        FileParser movieFile = new FileParser("movies.dat", "::");
        MovieMapper movieMapper = new MovieMapper(movieFile, 3);
        return new MovieInfo(movieMapper.getIdMovieMap());
    }
}

Answer 1

很难判断您的设计，因为不清楚您的应用程序将如何更改，特别是您发布的代码是在应用程序的根目录（main方法）中编写的，欢迎更改。

为了提出更好的设计，我认为：

将更改创建XXXInfo的方式，例如它们可以从SQL数据库，网络中加载和处理...
Statistics，DisplayStatistics和UserInterface的合成发生在您应用中除main方法之外的其他地方，这意味着您可能想在另一个应用程序中重用此合成代码。

下面是代码：

interface InfoLoader {
    RatingInfo loadRatingInfo();
    CustomerInfo loadCustomerInfo();
    MovieInfo loadMovieInfo();
}

class FileInfoLoader implements InfoLoader {
    public RatingInfo loadRatingInfo() {
        FileParser ratingsFile = new FileParser("ratings.dat", "::");
        RatingsMapper ratingsMapper = new RatingsMapper(ratingsFile, 4);
        return new RatingInfo(ratingsMapper.getCustomerIDMovieIDRatingAndTimeMap());
    }
    public CustomerInfo loadCustomerInfo () {
        FileParser customerFile = new FileParser("users.dat", "::");
        CustomerMapper customerMapper = new CustomerMapper(customerFile, 5);
        return new CustomerInfo(customerMapper.getIdCustomerMap());
    }
    public MovieInfo loadMovieInfo () {
        FileParser movieFile = new FileParser("movies.dat", "::");
        MovieMapper movieMapper = new MovieMapper(movieFile, 3);
        return new MovieInfo(movieMapper.getIdMovieMap());
    }
}

class App {
    public App(InfoLoader infoLoader) {
        this.infoLoader = infoLoader;
    }
    public void start() {
        Statistics stat = new Statistics(
            infoLoader.loadCustomerInfo(),
            infoLoader.loadMovieInfo(),
            infoLoader.loadRatingInfo()
        );
        DisplayStatistics ds = new DisplayStatistics(stat);
        UserInterface ui = new UserInterface(ds);
        ui.start();
    }
    private InfoLoader infoLoader;
}

public class Application {
    public static void main(String[] args) {
        InfoLoader infoLoader = new FileInfoLoader();
        // or InfoLoader infoLoader = new SqlInfoLoader();
        App app = new App(infoLoader);
        app.start();
    }
}

重构代码中的问题/弄清楚要使用的设计模式

1 个答案: