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.lesson04.Main;

import java.util.Scanner;

/**
 *
 * @author diepvan
 */
public class Book {
    String bookName, authorName;
    int pageNum;
    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 String getBookName() {
        return bookName;
    }

    public void setBookName(String bookName) {
        this.bookName = bookName;
    }

    public String getAuthorName() {
        return authorName;
    }

    public void setAuthorName(String authorName) {
        this.authorName = authorName;
    }

    public int getPageNum() {
        return pageNum;
    }

    public void setPageNum(int pageNum) {
        this.pageNum = pageNum;
    }

    public float getPrice() {
        return price;
    }

    public void setPrice(float price) {
        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 tien: ");
        price = Float.parseFloat(scan.nextLine());
    }
    
    public void display() {
        System.out.println(toString());
//        System.out.println(this);
    }

    @Override
    public String toString() {
        return "bookName=" + bookName + ", authorName=" + authorName + ", pageNum=" + pageNum + ", price=" + price;
    }
}

#BT991.java

/*
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 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package com.gokisoft.lesson04.Main;

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

/**
 *
 * @author diepvan
 */
public class BT991 {

    public static void main(String[] args) {
        //Bai 1:
//        Book b1 = new Book();
//        b1.input();
//        
//        b1.display();
//        
//        Scanner scan = new Scanner(System.in);
//        
//        System.out.println("Nhap ten sach: ");
//        String bookName = scan.nextLine();
//        System.out.println("Nhap tac gia: ");
//        String authorName = scan.nextLine();
//        System.out.println("Nhap so trang: ");
//        int pageNum = Integer.parseInt(scan.nextLine());
//        System.out.println("Nhap gia tien: ");
//        float price = Float.parseFloat(scan.nextLine());
//        
//        Book b2 = new Book(bookName, authorName, pageNum, price);
//        b2.display();

        //Bai 2:
        ArrayList<Product> productList = new ArrayList<>();
        int choose;
        Scanner scan = new Scanner(System.in);

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

            switch (choose) {
                case 1: {
                    System.out.println("Nhap so san pham can them N = ");
                    int N = Integer.parseInt(scan.nextLine());

//                    Product p = new Product();
                    Product p;
                    for (int i = 0; i < N; i++) {
//                        Product p = new Product();
                        p = new Product();
                        p.input();

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

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

#C2109L.java

/*
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 */

package com.gokisoft.lesson04.Main;

/**
 *
 * @author diepvan
 */
public class C2109L {

    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

#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.lesson04.Main;

import java.util.Scanner;

/**
 *
 * @author diepvan
 */
public class Product {
    String title, nsx;
    float price;

    public Product() {
    }

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

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getNsx() {
        return nsx;
    }

    public void setNsx(String nsx) {
        this.nsx = nsx;
    }

    public float getPrice() {
        return price;
    }

    public void setPrice(float price) {
        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 nsx: ");
        nsx = scan.nextLine();
        System.out.println("Nhap gia ban: ");
        price = Float.parseFloat(scan.nextLine());
    }
    
    public void display() {
        System.out.println(toString());
    }

    @Override
    public String toString() {
        return "title=" + title + ", nsx=" + nsx + ", price=" + price;
    }
    
    
}