Java:带有涉及数组的方法的 Switch 语句

Question

大家好，我目前正在创建一个程序，允许用户创建数组、搜索数组以及从数组中删除元素。查看 LibraryMenu 方法，在 switch 语句中创建数组的第一种情况工作正常，但是当我尝试编译时，其他情况会产生“找不到符号错误”。

我的问题是我希望搜索和删除函数引用第一个开关案例 - 创建库数组。任何帮助都会受到赞赏，即使它可能来自一个简单的错误。

import java.util.*;
public class EnterLibrary
{

public static void LibraryMenu()
    {
        java.util.Scanner scannerObject =new java.util.Scanner(System.in);
        LibraryMenu Menu = new LibraryMenu();
        Menu.displayMenu();
        switch (scannerObject.nextInt() )
        {
            case '1':
            {
                System.out.println ("1 - Add Videos");
                Library[] newLibrary;
                newLibrary = createLibrary();
            }
            break;
            case '2':
                System.out.println ("2 - Search Videos");
                searchLibrary(newLibrary);
                break;
            case '3':
            {
                System.out.println ("3 - Change Videos");
                    //Change video method TBA
            }
            break;      
            case '4':
                System.out.println ("4 - Delete Videos");
                deleteVideo(newLibrary);
                break;
            default:
                System.out.println ("Unrecognized option - please select options 1-3 ");
                break;
        }
    }

public static Library[] createLibrary()
{
    Library[] videos = new Library[4];
    java.util.Scanner scannerObject =new java.util.Scanner(System.in); 
    for (int i = 0; i < videos.length; i++)
    {
        //User enters values into set methods in Library class
        System.out.print("Enter video number: " + (i+1) + "\n");
        String number = scannerObject.nextLine();
        System.out.print("Enter video title: " + (i+1) + "\n");
        String title = scannerObject.nextLine();
        System.out.print("Enter video publisher: " + (i+1) + "\n");
        String publisher = scannerObject.nextLine();
        System.out.print("Enter video duration: " + (i+1) + "\n");
        String duration = scannerObject.nextLine();
        System.out.print("Enter video date: " + (i+1) + "\n");
        String date= scannerObject.nextLine();
        System.out.print("VIDEO " + (i+1) + " ENTRY ADDED " + "\n \n");
        //Initialize arrays
        videos[i] = new Library ();
        videos[i].setVideo( number, title, publisher, duration, date  );
    }
    return videos;
}

public static void printVidLibrary( Library[] videos)
{
    //Get methods to print results
    System.out.print("\n======VIDEO CATALOGUE====== \n");
    for (int i = 0; i < videos.length; i++)
    {
        System.out.print("Video number " + (i+1) + ": \n" + videos[i].getNumber() + "\n ");
        System.out.print("Video title " + (i+1) + ": \n" + videos[i].getTitle() + "\n ");
        System.out.print("Video publisher " + (i+1) + ": \n" + videos[i].getPublisher() + "\n ");
        System.out.print("Video duration " + (i+1) + ": \n" + videos[i].getDuration() + "\n ");
        System.out.print("Video date " + (i+1) + ": \n" + videos[i].getDate() + "\n ");
    }
}

public static Library searchLibrary( Library[] videos)
{
    //User enters values to setSearch
    Library titleResult = new Library();
    java.util.Scanner scannerObject =new java.util.Scanner(System.in); 
    for (int n = 0; n < videos.length; n++)
    {
        System.out.println("Search for video number:\n");
        String newSearch = scannerObject.nextLine();
        titleResult.getSearch( videos, newSearch);

        if (!titleResult.equals(-1))
        {
        System.out.print("Match found!\n" + newSearch + "\n");
        }
        else if (titleResult.equals(-1))
        {
        System.out.print("Sorry, no matches found!\n");
        }
    }
    return titleResult;
}

public static void deleteVideo( Library[] videos)
{
    Library titleResult = new Library();
    java.util.Scanner scannerObject =new java.util.Scanner(System.in); 
    for (int n = 0; n < videos.length; n++)
    {
        System.out.println("Search for video number:\n");
        String deleteSearch = scannerObject.nextLine();
        titleResult.deleteVideo(videos, deleteSearch);
        System.out.print("Video deleted\n");
    }
}



public static void main(String[] args)
{
    Library[] newLibrary;

    new LibraryMenu();
}
}

Answer 1

我认为这是一个糟糕的设计。您将太多的东西混合在一起:用户界面、逻辑、数据结构。

首先将 LibraryArray 与 LibraryMenu 隔离。您根本不应该在其中看到任何开关或输入或输出。

Java 是一种面向对象的语言。开始从对象的角度思考您的系统。我没有看到 Video 和 VideoCatalog 之类的类。如果您创建了这个系统，您会发现它更容易实现。

看起来你已经开始了:

package model;

public class Video {
    private Long id;
    private String title;
    private String publisher;
    private int durationSeconds;
    private Date publicationDate;
    // add ctors, getters, etc.  Immutable?  Could be...
    // equals, hash code, toString
}

让您的 VideoCatalog 远离用户界面或 I/O:

package model;

public interface VideoCatalog {
    List<Video> find();
    List<Video> find(String title);
    List<Video> find(Date startDate, Date endDate) ;
    Long save(Video video);
    void update(Video video);
    void delete(Video video);
}

现在您可以拥有一个使用您想要的任何数据结构的实现:

package model;

public class VideoCatalogImpl implements VideoCatalog {
    private Set<Video> videos; 
    // add implementations here.
}