重构代码/计算要使用的设计模式中的问题

Question

因此，在java项目的Application ( main )类的Main方法中，我有很多行代码要执行。为了消除所有的杂乱，我最后用提取方法重构技术重构了它，但是在主类中我得到了很多静态方法，我不喜欢.有什么更好的方法来获得一个干净的主应用方法？我应该使用一个单例类吗?我应该使用什么其他的设计模式/技术来避免在我的主类中使用所有这些静态方法，并尽可能地保持主方法的简洁性？

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());
    }

}

在使用单例类(处理器)：后更改代码

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();
    }


}

单例类(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，因为尚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欢迎更改的应用程序(main方法)的根目录中编写的。

为了提出更好的设计，我想：

1. 创建XXXInfo的方式将被改变，例如它们可以从SQL数据库、网络中加载和处理。
2. Statistics、DisplayStatistics和UserInterface的组合发生在应用程序中的某个地方，而不是main方法，这意味着您可能希望在另一个代码中重用这个组合。

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();
    }
}