By GokiSoft.com| 15:31 14/06/2023|
Java Basic

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

Bài tập 1:

Tạo class Book có các thuộc tính: Tên sách, tác giả số trang, giá tiền.

-       Tạo 2 constructor (1 có tham số và một không có tham số).

-       Tạo phương thức nhập và hiển thị.

Tạo class BookTest và khai báo hàm main.

-       Tạo 2 đối tượng của lớp Book. Một đối tượng được khởi tạo bằng constructor không có tham số và sau đó gọi hàm nhập.

-       Đối tượng còn lại khởi tạo bằng constructor có tham số.

Gọi phương thức hiển thị của 2 đối tượng này.

 

Bài tập 2:

Tạo class Product gồm các thuộc tính:

-       Tên hàng hóa

-       Nhà sản xuất

-       Giá bán

+ Tạo 2 constructor cho lớp này.

+ Cài đặt hàm nhập và hiển thị.

 

Tạo class ProductMenu, khai báo hàm main và tạo menu sau:

1.    Nhập thông tin cho n sản phẩm

2.    Hiển thị thông tin vừa nhập

3.    Sắp xếp thông tin giảm dần theo giá và hiển thị

4.    Thoát.

Phản hồi từ học viên

5

(Dựa trên đánh giá ngày hôm nay)

Nguyễn Chí Tâm [java2_online,java1_online]
Nguyễn Chí Tâm

2022-12-19 04:33:50



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


public class TestProduct {
    public static void main(String[] args) {
        Scanner scan0 = new Scanner(System.in);
        ArrayList<Product> list = new ArrayList<>();
        int choose;
        do{
            Getmenu();
            choose = scan0.nextInt();
            switch (choose){
                case 1 :{
                    Product pro = new Product();
                    pro.Nhap();
                    list.add(pro);
                    
                    
                }break;
                case 2 : {
                    for(Product a : list){
                        a.Display();
                    }
                    
                }break;
                case 3:{
                    Product t;
                    for (int i=0;i<list.size()-1;i++){
                       for (int j=0;j<list.size()-1;j++){
                           if (list.get(j).gia<list.get(j+1).gia ){
                               t=list.get(j);
                               list.remove(j);
                               list.add(j+1, t);
                           }
                       }
                   }
                    for (Product x : list){
                        x.Display();
                    }
                    
                       
                    
                        
                    
                }break;
            
            
            }}while (choose !=4);
        
        
        
    }  
    
    public static void Getmenu(){
        System.out.println("Menu: \n 1. Nhap thong tin san pham \n 2. Hien thi thong tin san pham \n "
                + "3. Thong tin giamr dan theo gia \n 4. thoat \n choose:");
    }
}

// create class product://
import java.util.Scanner;


public class Product {
    String tenhh,nhasx;
    int gia;

    public Product() {
    }

    public Product(String tenhh, String nhasx, int gia) {
        this.tenhh = tenhh;
        this.nhasx = nhasx;
        this.gia = gia;
    }
    public void Nhap(){
        Scanner scan0= new Scanner(System.in);
        System.out.println("Nhap ten hang hoa: "); tenhh = scan0.nextLine();
        System.out.println("Nhap ten nha san xuat: "); nhasx = scan0.nextLine();
        System.out.println("Nhap gia hang hoa: "); gia= scan0.nextInt();
    }
    
    public void Display(){
        System.out.println(tenhh+" "+nhasx+" "+gia);
       

    }
    
}



Hoàng Anh [community,C2010G]
Hoàng Anh

2021-07-04 16:27:13

Bài 1


Book.java
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package javaapplication4;
import java.util.Scanner;

/**
 *
 * @author Bom1
 */
public class Book {
    String name;
    String author;
    int page;
    double cost;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public int getPage() {
        return page;
    }

    public void setPage(int page) {
        this.page = page;
    }

    public double getCost() {
        return cost;
    }

    public void setCost(double cost) {
        this.cost = cost;
    }
    public void input(){
        Scanner input = new Scanner(System.in);
        
        System.out.println("Nhập tên sách: ");
        name = input.nextLine();
        System.out.println("Nhập tên tác giả: ");
        author = input.nextLine();
        System.out.println("Nhập số trang: ");
        page = input.nextInt();
        System.out.println("Nhập giá sách: ");
        cost = input.nextDouble();
    }
    public void display(){
        System.out.format("\nTên sách: %s\n Tên tác giả: %s\n Số trang: %d\n Giá sách: %f", name,author,page,cost);
    }
}


BookTest.java
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package javaapplication4;

/**
 *
 * @author Bom1
 */
public class BookTest {
    public static void main(String[] args) {
        Book book = new Book();
        book.input();
        book.display();
        
        Book book1 = new Book();
        book1.setName("300 bài code thiếu nhi");
        book1.setAuthor("Bờm");
        book1.setPage(100);
        book1.setCost(200.000);
        book1.display();
    }
}



TRẦN VĂN ĐIỆP [Teacher]
TRẦN VĂN ĐIỆP

2021-01-29 07:30:19


#ProductMenu.java


/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package aptech.lesson04;

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

/**
 *
 * @author Diep.Tran
 */
public class ProductMenu {

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

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

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

//                    Product product = new Product(); Khai bao sai
                    for (int i = 0; i < n; i++) {
                        Product product = new Product();
                        product.input();

                        produceList.add(product);
                    }
                    break;
                case 2:
                    for (int i = 0; i < produceList.size(); i++) {
                        produceList.get(i).display();
                    }
                    break;
                case 3:
                    //Sap xep
                    Collections.sort(produceList, new Comparator<Product>() {
                        @Override
                        public int compare(Product o1, Product o2) {
                            if(o1.getPrice() < o2.getPrice()) {
                                return 1;
                            }
                            return -1;
                        }
                    });
                    
                    for (int i = 0; i < produceList.size(); i++) {
                        produceList.get(i).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 danh sach san pham");
        System.out.println("3. Sap xep");
        System.out.println("4. Thoat");
        System.out.println("Chon: ");
    }
}


#Product.java


/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package aptech.lesson04;

import java.util.Scanner;

/**
 *
 * @author Diep.Tran
 */
public class Product {
    String name, manufacturerName;
    float price;

    public Product() {
    }

    public Product(String name, String manufacturerName, float price) {
        this.name = name;
        this.manufacturerName = manufacturerName;
        this.price = price;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getManufacturerName() {
        return manufacturerName;
    }

    public void setManufacturerName(String manufacturerName) {
        this.manufacturerName = manufacturerName;
    }

    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: ");
        name = scan.nextLine();
        
        System.out.println("Nhap NSX: ");
        manufacturerName = scan.nextLine();
        
        System.out.println("Nhap gia: ");
        price = Float.parseFloat(scan.nextLine());
    }
    
    public void display() {
//        System.out.println(this);
//        String str = toString();
//        System.out.println(str);
//        System.out.println(toString());
//        System.out.println("Product{" + "name=" + name + ", manufacturerName=" + manufacturerName + ", price=" + price + '}');
        System.out.println("Name: " + name + ", manufacturerName: " + manufacturerName + ", price: " + price);
    }

    @Override
    public String toString() {
        return "Product{" + "name=" + name + ", manufacturerName=" + manufacturerName + ", price=" + price + '}';
    }
}



vuong huu phu [T2008A]
vuong huu phu

2021-01-26 04:00:09

Book.java


/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package buoi.pkg2;

import java.util.Scanner;

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

    public String ten_sach;
    public String tac_gia;
    public int so_trang;
    public float gia_tien;

    

    Book() {
    }

    Book(String a, String tacg, int i, float d) {
        ten_sach = a;
    tac_gia = tacg;
    so_trang = i;
    gia_tien = d;
    
    System.out.println("Ten sach: "+ten_sach);
        System.out.println("Ten tac gia: "+tac_gia);
        System.out.println("So trang: "+so_trang);
        System.out.println("Giatien: "+gia_tien);
    }

    public void khongcothamso() {
        Scanner scan = new Scanner(System.in);
        System.out.print("nhap ten sach: ");
        ten_sach = scan.nextLine();
        System.out.print("nhap ten tac gia: ");
        tac_gia = scan.nextLine();
        System.out.print("nhap so trang: ");
        so_trang = scan.nextInt();
        System.out.print("nhap gia tien: ");
        gia_tien = scan.nextFloat();
        System.out.println();
        System.out.println("Ten sach: "+ten_sach);
        System.out.println("Ten tac gia: "+tac_gia);
        System.out.println("So trang: "+so_trang);
        System.out.println("Giatien: "+gia_tien);
    }
    

}



vuong huu phu [T2008A]
vuong huu phu

2021-01-26 03:59:12

main


/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package buoi.pkg2;

/**
 *
 * @author Admin
 */
public class book_test {
    public static void main(String[] args) {
    Book book = new Book();
    book.khongcothamso();
    System.out.println();
    Book book1 = new Book("abcd","tac gia 1",12, (float) 14.000);
    
    }
}



Đặng Trần Nhật Minh [T2008A]
Đặng Trần Nhật Minh

2021-01-25 09:48:28


#Book.class
package javalesson3.Book;

import java.util.Scanner;

public class Book {
    
    public String name;
    public String author;
    public int num;
    public double price;
    
    public Book() {
        
    }
    
    public Book(String name, String author, int num, double price) {
    
        this.name = name;
        this.author = author;
        this.num = num;
        this.price = price;
        
    }
    
    public void input() {
        
        Scanner r = new Scanner(System.in);
        
        System.out.println("Name: ");
        this.name = r.nextLine();
        System.out.println("Author: ");
        this.author = r.nextLine();
        System.out.println("Num: ");
        this.num = r.nextInt();
        System.out.println("Price: ");
        this.price = r.nextDouble();
        
    }
    
    public void output() {
        
        System.out.println("Name: " + name);
        System.out.println("Author: " + author);
        System.out.println("Num: " + num);
        System.out.println("Price: " + price);
        
    }
        
}
#Test.class




package javalesson3.Book;

import java.util.Scanner;

public class Test {

    public static void main(String[] args) {
        
        Scanner r = new Scanner(System.in);
        
        Book book1 = new Book("The Miserable", "Victor Hugo", 1521, 15.234);
        
        Book book2 = new Book();
        book2.input();
        
        book1.output();
        book2.output();

    }

}



Nguyễn Tiến Đạt [T2008A]
Nguyễn Tiến Đạt

2021-01-25 09:04:13


Bai 1
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package lesson3;
import java.util.Scanner;

/**
 *
 * @author MyPC
 */
public class BookTest {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        
        Book book1 = new Book();
        book1.bookName = scan.nextLine();
        book1.authorName = scan.nextLine();
        book1.pageNumber = scan.nextInt();
        book1.price = scan.nextInt();
        book1.Display();
        
        Book book2 = new Book("De men phieu luu ky", "To Hoai", 300, 2032001);
        book2.Display();
    }
}



/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package lesson3;

/**
 *
 * @author MyPC
 */
public class Book {
    public String bookName , authorName;
    public int pageNumber , price;
    
    public Book(){
        
    }
    public Book(String bookName , String authorName , int pageNumber , int price){
        this.bookName = bookName;
        this.authorName = authorName;
        this.pageNumber = pageNumber;
        this.price = price;
    }
    
    public void Display(){
        System.out.format("\nName of book: %s\nName of author: %s\nNumber of pages: %d\nPrice: %d\n", bookName,authorName,pageNumber,price);
    }
}



Nguyễn Huy Hoàng [APROTRAIN_ADF]
Nguyễn Huy Hoàng

2020-06-04 14:06:24


import java.util.Scanner; /** * * @author std */ public class Book { String bookname; String author; int pageNo; double price; public Book() { } public Book(String bookname, String author, int pageNo, double price) { this.bookname = bookname; this.author = author; this.pageNo = pageNo; this.price = price; } public String getBookname() { return bookname; } public void setBookname(String bookname) { this.bookname = bookname; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public int getPageNo() { return pageNo; } public void setPageNo(int pageNo) { this.pageNo = pageNo; } public double getPrice() { return price; } public void setPrice(double price) { this.price = price; } public void input(){ Scanner scanner = new Scanner(System.in); System.out.println("Bookname"); bookname = scanner.nextLine(); System.out.println("Author"); author = scanner.nextLine(); System.out.println("Page numbers"); pageNo = Integer.parseInt(scanner.nextLine()); System.out.println("Price"); price = Double.parseDouble(scanner.nextLine()); } public void show(){ System.out.println(bookname + author + pageNo + price); } }



public class BookTest {
    public static void main(String[] args) {
        Book book2 = new Book();
        book2.input();
        Book book = new Book("ABC","abc",100,56.78);
        book2.show();
        book.show();
    }
}



cuonglee [C1907L]
cuonglee

2020-04-05 14:53:04



/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package QuanLiHangHoa;

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

/**
 *
 * @author Admin
 */
public class ProductMenu {
    public static void main(String[] args) {
        Scanner add = new Scanner(System.in);
        ArrayList<Product> list = new ArrayList();// khoi tao mot array list
        int choose,n;
        
          do{
            show();
            choose = add.nextInt();
            switch(choose){
                case 1:
                    System.out.println("nhap thong tin  nsan pham");
                    System.out.println("nhap n");
                    n = add.nextInt();
                    for(int i = 0; i < n; i++){ 
                        Product prd = new Product();
                         prd.nhap();
                        list.add(prd);
                    }
                    break;
                case 2:
                    System.out.println("hien thi thong tin san pham");
                     for(int i = 0; i < list.size(); i++){
                        list.get(i).xuat();
                    }
                    break;
                case 3:
                    System.out.println("sap xep");
            }
        }while(choose != 4);
    }
    
    public static void show(){
        System.out.println("1. Nhap thong tin N san pham.");
        System.out.println("2. Hien thi thong tin vua nhap.");
        System.out.println("3. Sap xem thong tin giam dan theo gia va hien thi");
        System.out.println("4. Thoat");
        System.out.println("==============================");
    }
  
}



/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package QuanLiHangHoa;

import java.util.Scanner;

/**
 *
 * @author Admin
 */
public class Product {
    String tenHangHoa,nhaSanXuat;
    int giaBan;
    int n;

    public Product() {
    }

    public Product(String tenHangHoa, String nhaSanXuat, int giaBan) {
        this.tenHangHoa = tenHangHoa;
        this.nhaSanXuat = nhaSanXuat;
        this.giaBan = giaBan;
    }

    public String getTenHangHoa() {
        return tenHangHoa;
    }

    public void setTenHangHoa(String tenHangHoa) {
        this.tenHangHoa = tenHangHoa;
    }

    public String getNhaSanXuat() {
        return nhaSanXuat;
    }

    public void setNhaSanXuat(String nhaSanXuat) {
        this.nhaSanXuat = nhaSanXuat;
    }

    public int getGiaBan() {
        return giaBan;
    }

    public void setGiaBan(int giaBan) {
        this.giaBan = giaBan;
    }
    
    public void nhap(){
        Scanner input = new Scanner(System.in);
        System.out.println("nhap ten hang hoa");
        tenHangHoa = input.nextLine();
        System.out.println("nhap nha san xuat");
        nhaSanXuat = input.nextLine();
        System.out.println("nhap gia ban");
        giaBan = input.nextInt();
    }
    
    public void xuat(){
        System.out.println("ten hang hoa: " + tenHangHoa);
        System.out.println("nha san xuat: " + nhaSanXuat);
        System.out.println("gia ban: " + giaBan);
    }
    
    
}



cuonglee [C1907L]
cuonglee

2020-04-03 14:34:39



/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package quanLiBook;

/**
 *
 * @author Admin
 */
public class BookTest {
    public static void main(String[] args) {
        Book bk1 = new Book();
        Book bk2 = new Book();
         bk1.nhap();
         bk1.xuat();
         bk2.xuat();
    }
}


/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package quanLiBook;

import java.util.Scanner;


/**
 *
 * @author Admin
 */
public class Book {
    String tenSach,tacGia;
    int soTrang,soTien;

    public Book(){
            
         
    }
     public Book(String tenSach, String tacGia, int soTrang, int soTien) {
       
        this.tenSach = tenSach;
        this.tacGia = tacGia;
        this.soTrang = soTrang;
        this.soTien = soTien;
    }
    public void nhap(){
        Scanner add = new Scanner(System.in);
        System.out.println("nhap ten sach");
        tenSach = add.nextLine();
        System.out.println("nhap ten tac gia");
        tacGia = add.nextLine();
        System.out.println("nhap so trang");
        soTrang = add.nextInt();
        System.out.println("nhap so tien");
        soTien = add.nextInt();
    }
    public void xuat(){
        System.out.println(tenSach);
        System.out.println(tacGia);
        System.out.println(soTrang);
        System.out.println(soTien);
    }
}