Map练习-图书管理系统

ゝ一世哀愁。 2023-10-07 18:38 6阅读 0赞

> **图书管理系统之** **Book** **类**

public class Book {
        private String name;
        private double price;
        
        public Book() {
        }
        
        public Book(String name, double price) {
            this.name = name;
            this.price = price;
        }
        
        public String getName() {
            return name;
        }
        
        public void setName(String name) {
            this.name = name;
        }
        
        public double getPrice() {
            return price;
        }
        
        public void setPrice(double price) {
            this.price = price;
        }
        
        @Override
        public String toString() {
            return "Book{" +
                    "name='" + name + '\'' +
                    ", price=" + price +
                    '}';
        }
    }

> **图书管理系统之主界面和选择的实现**

public class BookManger {
        public static void main(String[] args) {
            HashMap<String, ArrayList<Book>> map = new HashMap<>();
             创建集合对象，用于存储书籍数据
            ArrayList<Book> it = new ArrayList<>();
            it.add(new Book("java从入门到放弃",23.1));
            it.add(new Book("mybatis",34.5));
            map.put("it书籍",it);
            
            ArrayList<Book> mz = new ArrayList<>();
            mz.add(new Book("西游记",23.1));
            mz.add(new Book("水浒传",35.5));
            map.put("名著",mz);
            
            while (true){
                //学生管理系统的主页面
                System.out.println("------------------欢迎来到学生管理系统-------------------");
                System.out.println("                  1.查看所有书籍");
                System.out.println("                  2.添加书籍");
                System.out.println("                  3.删除书籍");
                System.out.println("                  4.修改书籍");
                System.out.println("                  5.退出");
                System.out.println("                  请输入您的选择");
                
                //创建键盘录入对象
                Scanner sc = new Scanner(System.in);
                int num = sc.nextInt();
                switch (num){
                    case 1:
                        findAllBook(map);
                        break;
                    case 2:
                        addBook(map);
                        break;
                    case 3:
                        deleteBook(map);
                        break;
                    case 4:
                        updateBook(map);
                        break;
                    case 5:
                        System.out.println("谢谢您的使用");
                        System.exit(0);
                        break;
                    default:
                        System.out.println("输入有误，清重新输入");
                        break;
                }
            }
        }
        
        private static void updateBook(HashMap<String, ArrayList<Book>> map) {
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入要修改的书籍类型");
            String type = sc.next();
            if (map.get(type)==null){
                System.out.println("您修改的书籍类型不存在");
                return;
            }
            
            System.out.println("请输入要修改的书籍名称");
            String oldName = sc.next();
    
            System.out.println("请输入新书籍名称");
            String newName = sc.next();
            System.out.println("请输入新书籍价格");
            Double price = sc.nextDouble();
        
            ArrayList<Book> books = map.get(type);
            for (int i = 0; i < books.size(); i++) {
                Book book = books.get(i);
                if (book.getName().equals(oldName)){
                    // 找到这本书,修改这本书
                    book.setName(newName);
                    book.setPrice(price);
                    System.out.println("修改成功");
                    return;
                }
            }
            System.out.println("没有找到"+oldName+"书籍");
        }
        
        private static void deleteBook(HashMap<String, ArrayList<Book>> map) {
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入要删除的书籍类型");
            String type = sc.next();
            System.out.println("请输入要删除的书籍名称");
            String name = sc.next();
    
            ArrayList<Book> books = map.get(type);
            if (map.get(type)==null){
                System.out.println("您删除的书籍类型不存在");
                return;
            }
        
            for (int i = 0; i < books.size(); i++) {
                Book book = books.get(i);
                if (book.getName().equals(name)){
                    books.remove(i);
                    System.out.println("删除"+name+"成功");
                    return;
                }
            }
            System.out.println("您删除的书籍不存在");
        }
        
        private static void addBook(HashMap<String, ArrayList<Book>> map) {
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入要添加的书籍类型");
            String type = sc.next();
            System.out.println("请输入要添加的书籍名称");
            String name = sc.next();
            System.out.println("请输入要添加的书籍价格");
            Double price = sc.nextDouble();
            Book book = new Book(name,price);
        
            // 拿到书籍列表
            ArrayList<Book> books = map.get(type);
            if (books==null){
                // 如果书籍列表不存在创建一个书籍列表
                books = new ArrayList<>();
                map.put(type, books);
            }
            // 将书添加到集合中
            books.add(book);
            System.out.println("添加" +name+"成功");
        }
        
        private static void findAllBook(HashMap<String, ArrayList<Book>> map) {
            System.out.println("类型\t\t书名\t\t价格");
            Set<Map.Entry<String, ArrayList<Book>>> entries = map.entrySet();
            for (Map.Entry<String, ArrayList<Book>> entry : entries) {
                String key = entry.getKey();
                System.out.println(key);
            
                ArrayList<Book> value = entry.getValue();
                for (Book book : value) {
                    System.out.println("\t\t" + book.getName() + "\t" + book.getPrice());
                }
            }
        }
    }