如何通过一个图书管理系统案例综合运用Java的CRUD操作

wen java案例 2026-06-05 315

本文目录导读：

项目结构
数据模型层 (Model)
数据库工具类
数据访问层 (DAO)
业务逻辑层 (Service)
用户界面层 (UI) - 控制台版本
数据库脚本
Maven依赖配置

我来通过一个完整的图书管理系统案例，展示如何综合运用Java的CRUD（Create, Read, Update, Delete）操作。

项目结构

book-management-system/
├── src/
│   ├── model/          # 数据模型
│   ├── dao/            # 数据访问层
│   ├── service/        # 业务逻辑层
│   └── ui/             # 用户界面层
└── resources/
    └── database.sql    # 数据库脚本

数据模型层 (Model)

// Book.java - 图书实体类
package model;
import java.util.Date;
public class Book {
    private Long id;
    private String isbn;
    private String title;
    private String author;
    private String publisher;
    private Date publishDate;
    private Double price;
    private Integer stock;        // 库存数量
    private String category;      // 分类
    private String status;        // 状态：AVAILABLE/BORROWED/MAINTENANCE
    // 构造函数
    public Book() {}
    public Book(String isbn, String title, String author, String publisher,
                Date publishDate, Double price, Integer stock, String category) {
        this.isbn = isbn;
        this.title = title;
        this.author = author;
        this.publisher = publisher;
        this.publishDate = publishDate;
        this.price = price;
        this.stock = stock;
        this.category = category;
        this.status = "AVAILABLE";
    }
    // Getter和Setter方法
    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public String getIsbn() { return isbn; }
    public void setIsbn(String isbn) { this.isbn = isbn; }
    // ... 其他getter和setter方法
    @Override
    public String toString() {
        return "Book{" +
                "id=" + id +
                ", isbn='" + isbn + '\'' +
                ", title='" + title + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", stock=" + stock +
                '}';
    }
}

数据库工具类

// DBUtil.java
package util;
import java.sql.*;
public class DBUtil {
    private static final String URL = "jdbc:mysql://localhost:3306/book_management";
    private static final String USER = "root";
    private static final String PASSWORD = "password";
    // 获取数据库连接
    public static Connection getConnection() throws SQLException {
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            return DriverManager.getConnection(URL, USER, PASSWORD);
        } catch (ClassNotFoundException e) {
            throw new SQLException("数据库驱动加载失败", e);
        }
    }
    // 关闭资源
    public static void close(Connection conn, Statement stmt, ResultSet rs) {
        try {
            if (rs != null) rs.close();
            if (stmt != null) stmt.close();
            if (conn != null) conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

数据访问层 (DAO)

// BookDAO.java - 图书数据访问对象
package dao;
import model.Book;
import util.DBUtil;
import java.sql.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
public class BookDAO {
    // CREATE - 添加图书
    public boolean addBook(Book book) {
        String sql = "INSERT INTO books (isbn, title, author, publisher, publish_date, " +
                    "price, stock, category, status) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)";
        try (Connection conn = DBUtil.getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
            pstmt.setString(1, book.getIsbn());
            pstmt.setString(2, book.getTitle());
            pstmt.setString(3, book.getAuthor());
            pstmt.setString(4, book.getPublisher());
            pstmt.setDate(5, new java.sql.Date(book.getPublishDate().getTime()));
            pstmt.setDouble(6, book.getPrice());
            pstmt.setInt(7, book.getStock());
            pstmt.setString(8, book.getCategory());
            pstmt.setString(9, book.getStatus());
            int affectedRows = pstmt.executeUpdate();
            if (affectedRows > 0) {
                // 获取自增ID
                ResultSet rs = pstmt.getGeneratedKeys();
                if (rs.next()) {
                    book.setId(rs.getLong(1));
                }
                return true;
            }
            return false;
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }
    // READ - 查询所有图书
    public List<Book> getAllBooks() {
        List<Book> books = new ArrayList<>();
        String sql = "SELECT * FROM books ORDER BY id DESC";
        try (Connection conn = DBUtil.getConnection();
             Statement stmt = conn.createStatement();
             ResultSet rs = stmt.executeQuery(sql)) {
            while (rs.next()) {
                books.add(mapBook(rs));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return books;
    }
    // READ - 根据ID查询图书
    public Book getBookById(Long id) {
        String sql = "SELECT * FROM books WHERE id = ?";
        try (Connection conn = DBUtil.getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {
            pstmt.setLong(1, id);
            ResultSet rs = pstmt.executeQuery();
            if (rs.next()) {
                return mapBook(rs);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }
    // READ - 根据关键字搜索图书
    public List<Book> searchBooks(String keyword) {
        List<Book> books = new ArrayList<>();
        String sql = "SELECT * FROM books WHERE title LIKE ? OR author LIKE ? OR isbn LIKE ?";
        try (Connection conn = DBUtil.getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {
            String searchPattern = "%" + keyword + "%";
            pstmt.setString(1, searchPattern);
            pstmt.setString(2, searchPattern);
            pstmt.setString(3, searchPattern);
            ResultSet rs = pstmt.executeQuery();
            while (rs.next()) {
                books.add(mapBook(rs));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return books;
    }
    // UPDATE - 更新图书信息
    public boolean updateBook(Book book) {
        String sql = "UPDATE books SET isbn=?, title=?, author=?, publisher=?, " +
                    "publish_date=?, price=?, stock=?, category=?, status=? WHERE id=?";
        try (Connection conn = DBUtil.getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {
            pstmt.setString(1, book.getIsbn());
            pstmt.setString(2, book.getTitle());
            pstmt.setString(3, book.getAuthor());
            pstmt.setString(4, book.getPublisher());
            pstmt.setDate(5, new java.sql.Date(book.getPublishDate().getTime()));
            pstmt.setDouble(6, book.getPrice());
            pstmt.setInt(7, book.getStock());
            pstmt.setString(8, book.getCategory());
            pstmt.setString(9, book.getStatus());
            pstmt.setLong(10, book.getId());
            return pstmt.executeUpdate() > 0;
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }
    // DELETE - 删除图书
    public boolean deleteBook(Long id) {
        String sql = "DELETE FROM books WHERE id = ?";
        try (Connection conn = DBUtil.getConnection();
             PreparedStatement pstmt = conn.prepareStatement(sql)) {
            pstmt.setLong(1, id);
            return pstmt.executeUpdate() > 0;
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }
    // 辅助方法：将ResultSet映射为Book对象
    private Book mapBook(ResultSet rs) throws SQLException {
        Book book = new Book();
        book.setId(rs.getLong("id"));
        book.setIsbn(rs.getString("isbn"));
        book.setTitle(rs.getString("title"));
        book.setAuthor(rs.getString("author"));
        book.setPublisher(rs.getString("publisher"));
        book.setPublishDate(rs.getDate("publish_date"));
        book.setPrice(rs.getDouble("price"));
        book.setStock(rs.getInt("stock"));
        book.setCategory(rs.getString("category"));
        book.setStatus(rs.getString("status"));
        return book;
    }
}

业务逻辑层 (Service)

// BookService.java
package service;
import dao.BookDAO;
import model.Book;
import java.util.List;
public class BookService {
    private BookDAO bookDAO = new BookDAO();
    // 添加图书（带业务验证）
    public boolean addBook(Book book) {
        // 验证ISBN是否重复
        List<Book> existingBooks = bookDAO.searchBooks(book.getIsbn());
        if (!existingBooks.isEmpty()) {
            throw new RuntimeException("ISBN已存在");
        }
        // 验证必填字段
        if (book.getTitle() == null || book.getTitle().trim().isEmpty()) {
            throw new RuntimeException("书名不能为空");
        }
        if (book.getPrice() < 0) {
            throw new RuntimeException("价格不能为负数");
        }
        return bookDAO.addBook(book);
    }
    // 借书操作（更新库存）
    public boolean borrowBook(Long bookId) {
        Book book = bookDAO.getBookById(bookId);
        if (book == null) {
            throw new RuntimeException("图书不存在");
        }
        if (book.getStock() <= 0) {
            throw new RuntimeException("库存不足");
        }
        book.setStock(book.getStock() - 1);
        return bookDAO.updateBook(book);
    }
    // 还书操作（增加库存）
    public boolean returnBook(Long bookId) {
        Book book = bookDAO.getBookById(bookId);
        if (book == null) {
            throw new RuntimeException("图书不存在");
        }
        book.setStock(book.getStock() + 1);
        return bookDAO.updateBook(book);
    }
    // 其他业务方法...
    public List<Book> getAllBooks() {
        return bookDAO.getAllBooks();
    }
    public Book getBookById(Long id) {
        return bookDAO.getBookById(id);
    }
    public boolean updateBook(Book book) {
        return bookDAO.updateBook(book);
    }
    public boolean deleteBook(Long id) {
        return bookDAO.deleteBook(id);
    }
}

用户界面层 (UI) - 控制台版本

// MainUI.java
package ui;
import model.Book;
import service.BookService;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Scanner;
public class MainUI {
    private BookService bookService = new BookService();
    private Scanner scanner = new Scanner(System.in);
    private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    public void start() {
        while (true) {
            System.out.println("\n=== 图书管理系统 ===");
            System.out.println("1. 添加图书");
            System.out.println("2. 查看所有图书");
            System.out.println("3. 搜索图书");
            System.out.println("4. 更新图书信息");
            System.out.println("5. 删除图书");
            System.out.println("6. 借书");
            System.out.println("7. 还书");
            System.out.println("0. 退出");
            System.out.print("请选择操作: ");
            int choice = scanner.nextInt();
            scanner.nextLine(); // 消耗换行符
            switch (choice) {
                case 1:
                    addBook();
                    break;
                case 2:
                    viewAllBooks();
                    break;
                case 3:
                    searchBooks();
                    break;
                case 4:
                    updateBook();
                    break;
                case 5:
                    deleteBook();
                    break;
                case 6:
                    borrowBook();
                    break;
                case 7:
                    returnBook();
                    break;
                case 0:
                    System.out.println("感谢使用！");
                    return;
                default:
                    System.out.println("无效选择！");
            }
        }
    }
    // CREATE - 添加图书
    private void addBook() {
        try {
            System.out.println("\n=== 添加图书 ===");
            System.out.print("ISBN: ");
            String isbn = scanner.nextLine();
            System.out.print("书名: ");
            String title = scanner.nextLine();
            System.out.print("作者: ");
            String author = scanner.nextLine();
            System.out.print("出版社: ");
            String publisher = scanner.nextLine();
            System.out.print("出版日期 (yyyy-MM-dd): ");
            Date publishDate = sdf.parse(scanner.nextLine());
            System.out.print("价格: ");
            Double price = scanner.nextDouble();
            scanner.nextLine();
            System.out.print("库存数量: ");
            Integer stock = scanner.nextInt();
            scanner.nextLine();
            System.out.print("分类: ");
            String category = scanner.nextLine();
            Book book = new Book(isbn, title, author, publisher, 
                                publishDate, price, stock, category);
            if (bookService.addBook(book)) {
                System.out.println("图书添加成功，ID: " + book.getId());
            } else {
                System.out.println("图书添加失败");
            }
        } catch (Exception e) {
            System.out.println("添加失败: " + e.getMessage());
        }
    }
    // READ - 查看所有图书
    private void viewAllBooks() {
        System.out.println("\n=== 所有图书 ===");
        List<Book> books = bookService.getAllBooks();
        if (books.isEmpty()) {
            System.out.println("暂无图书");
            return;
        }
        for (Book book : books) {
            displayBook(book);
        }
    }
    // READ - 搜索图书
    private void searchBooks() {
        System.out.print("\n请输入搜索关键字: ");
        String keyword = scanner.nextLine();
        List<Book> books = bookService.getBookDAO().searchBooks(keyword);
        if (books.isEmpty()) {
            System.out.println("未找到相关图书");
            return;
        }
        System.out.println("找到 " + books.size() + " 本图书:");
        for (Book book : books) {
            displayBook(book);
        }
    }
    // UPDATE - 更新图书
    private void updateBook() {
        System.out.print("\n请输入要更新的图书ID: ");
        Long id = scanner.nextLong();
        scanner.nextLine();
        Book book = bookService.getBookById(id);
        if (book == null) {
            System.out.println("图书不存在");
            return;
        }
        System.out.println("当前图书信息:");
        displayBook(book);
        System.out.println("\n输入新信息 (直接回车保持不变):");
        System.out.print("书名 (" + book.getTitle() + "): ");
        String title = scanner.nextLine();
        if (!title.isEmpty()) book.setTitle(title);
        System.out.print("作者 (" + book.getAuthor() + "): ");
        String author = scanner.nextLine();
        if (!author.isEmpty()) book.setAuthor(author);
        System.out.print("价格 (" + book.getPrice() + "): ");
        String price = scanner.nextLine();
        if (!price.isEmpty()) book.setPrice(Double.parseDouble(price));
        if (bookService.updateBook(book)) {
            System.out.println("更新成功");
        } else {
            System.out.println("更新失败");
        }
    }
    // DELETE - 删除图书
    private void deleteBook() {
        System.out.print("\n请输入要删除的图书ID: ");
        Long id = scanner.nextLong();
        Book book = bookService.getBookById(id);
        if (book == null) {
            System.out.println("图书不存在");
            return;
        }
        System.out.println("即将删除的图书:");
        displayBook(book);
        System.out.print("确认删除? (y/n): ");
        String confirm = scanner.next();
        if (confirm.equalsIgnoreCase("y")) {
            if (bookService.deleteBook(id)) {
                System.out.println("删除成功");
            } else {
                System.out.println("删除失败");
            }
        }
    }
    // 借书
    private void borrowBook() {
        System.out.print("\n请输入要借阅的图书ID: ");
        Long id = scanner.nextLong();
        try {
            if (bookService.borrowBook(id)) {
                System.out.println("借阅成功");
            }
        } catch (Exception e) {
            System.out.println("借阅失败: " + e.getMessage());
        }
    }
    // 还书
    private void returnBook() {
        System.out.print("\n请输入要归还的图书ID: ");
        Long id = scanner.nextLong();
        try {
            if (bookService.returnBook(id)) {
                System.out.println("归还成功");
            }
        } catch (Exception e) {
            System.out.println("归还失败: " + e.getMessage());
        }
    }
    // 显示图书信息
    private void displayBook(Book book) {
        System.out.println("-------------------");
        System.out.println("ID: " + book.getId());
        System.out.println("ISBN: " + book.getIsbn());
        System.out.println("书名: " + book.getTitle());
        System.out.println("作者: " + book.getAuthor());
        System.out.println("出版社: " + book.getPublisher());
        System.out.println("出版日期: " + sdf.format(book.getPublishDate()));
        System.out.println("价格: " + book.getPrice());
        System.out.println("库存: " + book.getStock());
        System.out.println("分类: " + book.getCategory());
        System.out.println("状态: " + book.getStatus());
        System.out.println("-------------------");
    }
    // 主方法
    public static void main(String[] args) {
        new MainUI().start();
    }
}

数据库脚本

-- database.sql
CREATE DATABASE IF NOT EXISTS book_management;
USE book_management;
CREATE TABLE books (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    isbn VARCHAR(20) NOT NULL UNIQUE,VARCHAR(200) NOT NULL,
    author VARCHAR(100),
    publisher VARCHAR(100),
    publish_date DATE,
    price DECIMAL(10, 2),
    stock INT DEFAULT 0,
    category VARCHAR(50),
    status VARCHAR(20) DEFAULT 'AVAILABLE',
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);
-- 插入测试数据
INSERT INTO books (isbn, title, author, publisher, publish_date, price, stock, category) VALUES
('978-7-111-12345-6', 'Java编程思想', 'Bruce Eckel', '机械工业出版社', '2020-01-01', 89.00, 10, '计算机'),
('978-7-302-54321-0', '深入理解Java虚拟机', '周志明', '清华大学出版社', '2019-12-01', 79.00, 5, '计算机');

Maven依赖配置

<!-- pom.xml -->
<dependencies>
    <!-- MySQL驱动 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.33</version>
    </dependency>
</dependencies>

这个完整的图书管理系统案例展示了：