Java basic- OOP - căn bản - Tổng hợp ví dụ lập trính hướng đổi tượng trong java - mới bắt đầu với OOP

#Book.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package com.gokisoft.c2209i.bt991;

import java.util.Scanner;

/**
 *
 * @author teacher
 */
public class Book {

    public String bookName;
    public String authorName;
    public int pageNum;
    public float price;

    public Book() {
    }

    public Book(String bookName, String authorName, int pageNum, float price) {
        this.bookName = bookName;
        this.authorName = authorName;
        this.pageNum = pageNum;
        this.price = price;
    }

    public void input() {
        Scanner scan = new Scanner(System.in);

        System.out.println("Nhap ten sach: ");
        bookName = scan.nextLine();
        System.out.println("Nhap tac gia: ");
        authorName = scan.nextLine();
        System.out.println("Nhap so trang: ");
        pageNum = Integer.parseInt(scan.nextLine());
        System.out.println("Nhap gia: ");
        price = Float.parseFloat(scan.nextLine());
    }

    public void display() {
        System.out.format("\nTen sach: %s, ten tac gia: %s, so trang: %d, gia: %f",
                bookName, authorName, pageNum, price);
    }
}

#Main.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package com.gokisoft.c2209i.bt991;

/**
 *
 * @author teacher
 */
public class Main {
    public static void main(String[] args) {
        Book b1 = new Book();
        b1.input();
        
        Book b2 = new Book("LAP TRINH C", "TRAN VAN DIEP", 20, 200000);
        
        b1.display();
        b2.display();
    }
}

#Product.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package com.gokisoft.c2209i.bt991;

import java.util.Scanner;

/**
 *
 * @author teacher
 */
public class Product {
    public String title;
    public String manufacturer;
    public float price;

    public Product() {
    }

    public Product(String title, String manufacturer, float price) {
        this.title = title;
        this.manufacturer = manufacturer;
        this.price = price;
    }

    public void input() {
        Scanner scan = new Scanner(System.in);
        
        System.out.println("Nhap ten san pham: ");
        title = scan.nextLine();
        System.out.println("Nhap ten NSX: ");
        manufacturer = scan.nextLine();
        System.out.println("Nhap gia: ");
        price = Float.parseFloat(scan.nextLine());
    }
    
    public void display() {
        System.out.format("\nTen san pham: %s, NSX: %s, gia: %f\n", title, manufacturer, price);
    }
}

#Test.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package com.gokisoft.c2209i.bt991;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;

/**
 *
 * @author teacher
 */
public class Test {

    public static void main(String[] args) {
        ArrayList<Product> productList = new ArrayList<>();
        Scanner scan = new Scanner(System.in);
        int choose;

        do {
            showMenu();
            choose = Integer.parseInt(scan.nextLine());

            switch (choose) {
                case 1: {
                    System.out.println("Nhapso san pham N = ");
                    int n = Integer.parseInt(scan.nextLine());

//                    Product p = new Product(); (1)
                    Product p;//(3)
                    for (int i = 0; i < n; i++) {
//                        Product p = new Product(); (2)
                        p = new Product();//(3)
                        p.input();

                        productList.add(p);
                    }
                    break;
                }
                case 2:
                    System.out.println("Danh sach san pham: ");
                    for (Product p : productList) {
                        p.display();
                    }
                    break;
                case 3: {
                    Collections.sort(productList, new Comparator<Product>() {
                        @Override
                        public int compare(Product o1, Product o2) {
                            if(o1.price > o2.price) return 1;
                            return -1;
                        }
                    });
                    break;
                }
                case 4:
                    System.out.println("Thoat!!!");
                    break;
                default:
                    System.out.println("Nhap sai!!!");
                    break;
            }
        } while (choose != 4);
    }

    public static void showMenu() {
        System.out.println("1. Nhap N san pham");
        System.out.println("2. Hien thi");
        System.out.println("3. Sap xep");
        System.out.println("4. Thoat");
        System.out.println("Chon: ");
    }
}