Java图书库存统计实现方法详解

public class Book {
    private String isbn;        // 图书唯一编号
    private String title;       // 书名
    private String author;      // 作者
    private int stock;          // 库存数量
public Book(String isbn, String title, String author, int stock) {
    this.isbn = isbn;
    this.title = title;
    this.author = author;
    this.stock = stock;
}

// Getter 和 Setter 方法
public String getIsbn() { return isbn; }
public String getTitle() { return title; }
public int getStock() { return stock; }
public void setStock(int stock) { this.stock = stock; }

@Override
public String toString() {
    return "ISBN: " + isbn + ", 书名: " + title + ", 作者: " + author + ", 库存: " + stock;
}
}

import java.util.HashMap;
import java.util.Map;
public class BookInventory {
private Map books;
public BookInventory() {
    this.books = new HashMap<>();
}

// 添加图书（若已存在则更新库存）
public void addBook(Book book) {
    Book existing = books.get(book.getIsbn());
    if (existing != null) {
        existing.setStock(existing.getStock() + book.getStock());
    } else {
        books.put(book.getIsbn(), new Book(book.getIsbn(), book.getTitle(), book.getAuthor(), book.getStock()));
    }
}

// 减少库存（模拟借出或销售）
public boolean reduceStock(String isbn, int amount) {
    Book book = books.get(isbn);
    if (book == null || book.getStock() < amount) {
        return false;
    }
    book.setStock(book.getStock() - amount);
    return true;
}

// 增加库存（补货）
public void restock(String isbn, int amount) {
    Book book = books.get(isbn);
    if (book != null) {
        book.setStock(book.getStock() + amount);
    }
}

// 查询某本书信息
public Book findBook(String isbn) {
    return books.get(isbn);
}

// 统计总库存量
public int getTotalStock() {
    return books.values().stream().mapToInt(Book::getStock).sum();
}

// 显示所有图书库存
public void printAllBooks() {
    books.values().forEach(System.out::println);
}
}

public class Main {
    public static void main(String[] args) {
        BookInventory inventory = new BookInventory();
    // 添加图书
    inventory.addBook(new Book("978-1", "Java编程思想", "Bruce Eckel", 10));
    inventory.addBook(new Book("978-2", "算法导论", "Thomas Cormen", 5));

    // 补货
    inventory.restock("978-1", 5);

    // 借出
    inventory.reduceStock("978-2", 2);

    // 查看所有图书
    inventory.printAllBooks();

    // 输出总库存
    System.out.println("总库存量: " + inventory.getTotalStock());
}
}