Java 保存ArrayList条目

首先，这是我的代码

posit.java文件

package postit;

import java.util.Scanner;

class Postit {
  public static Scanner menu = new Scanner(System.in);
  public static void main(String[] args) {
    int MenuOption = 0;

    NewStorage G = new NewStorage();    // Case 1 Object

    while(MenuOption != 3){

        System.out.println(

                "\n--------Note System-------\n" +
                        "----------------------------\n" +
                        "1.   Create a Note \n" +
                        "2.   View Notes \n" +
                        "3.   Close Program\n" +
                        "----------------------------\n");

        MenuOption = menu.nextInt();
        menu.nextLine();

        switch (MenuOption) {

            case 1:

                G.printinfo();
                G.Notestore();

                break;

            case 2:

                G.viewNotes();
                G.printNotes();
                break;

            case 3:

                System.out.println("Program is closing");
                System.exit(0);

                break;

            default:

                System.out.println("Invalid choice.");

                break;
            }
        }
    }
}

package postit;

import java.util.Scanner;
import java.util.ArrayList;

class NewStorage  {

    ArrayList<Note> NoteArray = new ArrayList<Note>(20);

    public void printinfo() {
        System.out.println("--- Fill note here  ---");
    }

    public void Notestore() {

        System.out.println("Enter the note ID you wish to attach the note with\n\n");
        String inputIDnote = Postit.menu.nextLine();
        System.out.println("Enter your note\n\n");
        String noteDescription = Postit.menu.nextLine();
        NoteArray.add(new Note(inputIDnote, noteDescription));
    }

    public void viewNotes() {

        System.out.println("Please enter the number of the note you wish to view.");
        int count = 0;

        for (int i = 0 ; i < NoteArray.size(); i++) {
            System.out.println((count++) + ": "  + NoteArray.get(i).inputIDnote);
        }
    }

    public void printNotes(){

        int count = Postit.menu.nextInt();
        Postit.menu.nextLine();

        System.out.println(count + " " + NoteArray.get(count));
    }
}

package postit;

class Note {

    String inputIDnote;
    String noteDescription;
    public Note(String inputIDnote, String noteDescription) {
        this.inputIDnote = inputIDnote;
        this.noteDescription = noteDescription;
    }
    @Override
    public String toString() {
        return "ID: " + inputIDnote + " \n\nDescription: " + noteDescription;
    }

}

NewStorage.java文件

package postit;

import java.util.Scanner;

class Postit {
  public static Scanner menu = new Scanner(System.in);
  public static void main(String[] args) {
    int MenuOption = 0;

    NewStorage G = new NewStorage();    // Case 1 Object

    while(MenuOption != 3){

        System.out.println(

                "\n--------Note System-------\n" +
                        "----------------------------\n" +
                        "1.   Create a Note \n" +
                        "2.   View Notes \n" +
                        "3.   Close Program\n" +
                        "----------------------------\n");

        MenuOption = menu.nextInt();
        menu.nextLine();

        switch (MenuOption) {

            case 1:

                G.printinfo();
                G.Notestore();

                break;

            case 2:

                G.viewNotes();
                G.printNotes();
                break;

            case 3:

                System.out.println("Program is closing");
                System.exit(0);

                break;

            default:

                System.out.println("Invalid choice.");

                break;
            }
        }
    }
}

package postit;

import java.util.Scanner;
import java.util.ArrayList;

class NewStorage  {

    ArrayList<Note> NoteArray = new ArrayList<Note>(20);

    public void printinfo() {
        System.out.println("--- Fill note here  ---");
    }

    public void Notestore() {

        System.out.println("Enter the note ID you wish to attach the note with\n\n");
        String inputIDnote = Postit.menu.nextLine();
        System.out.println("Enter your note\n\n");
        String noteDescription = Postit.menu.nextLine();
        NoteArray.add(new Note(inputIDnote, noteDescription));
    }

    public void viewNotes() {

        System.out.println("Please enter the number of the note you wish to view.");
        int count = 0;

        for (int i = 0 ; i < NoteArray.size(); i++) {
            System.out.println((count++) + ": "  + NoteArray.get(i).inputIDnote);
        }
    }

    public void printNotes(){

        int count = Postit.menu.nextInt();
        Postit.menu.nextLine();

        System.out.println(count + " " + NoteArray.get(count));
    }
}

package postit;

class Note {

    String inputIDnote;
    String noteDescription;
    public Note(String inputIDnote, String noteDescription) {
        this.inputIDnote = inputIDnote;
        this.noteDescription = noteDescription;
    }
    @Override
    public String toString() {
        return "ID: " + inputIDnote + " \n\nDescription: " + noteDescription;
    }

}

所以请原谅我，因为我正在学习如何编写Java，所以这是我的第一个程序，所以如果你认为它写得很糟糕，那么你知道为什么

---

正如您所看到的，程序可以询问用户是否希望创建一个带有ID和便笺本身的便笺。然后，用户可以通过选择所列注释ID旁边的编号来查看创建的注释。所以当我关闭程序时，ArrayList显然被删除了。是否有办法在程序关闭后保存数组列表中的注释？因为我想稍后实现一个编辑功能，所以它将是一个有用的东西。

现在您需要了解

文件

，

文件编写器

/

文件阅读器

或

缓冲阅读器

/

缓冲编写器

。他总是有很好的辅导课。我认为你应该创建数据库来保存数组，从那里你可以访问数组进行编辑或从数组中删除。下一步是处理文件。请阅读有关持久性的内容。可能基于文件是最简单的，或者说是关系数据库。