用javaweb写图书管理系统

好的，下面是一个简单的图书管理系统的示例，使用Java Web技术实现。

1. 数据库设计

首先，我们需要设计数据库来存储图书信息。我们可以创建一个名为“library”的数据库，并在其中创建一个名为“books”的表来存储图书信息。该表包含以下字段：

id: 图书ID（自增长）
title: 图书标题
author: 作者
publisher: 出版社
price: 价格

2. 创建Java Web项目

接下来，我们需要创建一个Java Web项目。您可以使用Eclipse等IDE，或者手动创建项目文件夹和文件。

3. 创建实体类

我们需要创建一个Java类来表示图书对象。这个类应该包含与数据库表中的字段相对应的属性，以及getter和setter方法。

public class Book {
    private int id;
    private String title;
    private String author;
    private String publisher;
    private double price;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

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

    public String getAuthor() {
        return author;
    }

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

    public String getPublisher() {
        return publisher;
    }

    public void setPublisher(String publisher) {
        this.publisher = publisher;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }
}

4. 创建DAO类

我们需要创建一个DAO（数据访问对象）类，用于连接数据库并实现与图书相关的操作（如添加、删除、更新、查询等）。下面是一个简单的示例：

public class BookDAO {
    private Connection conn;

    public BookDAO() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/library";
            String user = "root";
            String password = "123456";
            conn = DriverManager.getConnection(url, user, password);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public List<Book> getAllBooks() {
        List<Book> books = new ArrayList<Book>();
        try {
            Statement stmt = conn.createStatement();
            String sql = "SELECT * FROM books";
            ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                Book book = new Book();
                book.setId(rs.getInt("id"));
                book.setTitle(rs.getString("title"));
                book.setAuthor(rs.getString("author"));
                book.setPublisher(rs.getString("publisher"));
                book.setPrice(rs.getDouble("price"));
                books.add(book);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return books;
    }

    public void addBook(Book book) {
        try {
            PreparedStatement stmt = conn.prepareStatement("INSERT INTO books(title, author, publisher, price) VALUES (?, ?, ?, ?)");
            stmt.setString(1, book.getTitle());
            stmt.setString(2, book.getAuthor());
            stmt.setString(3, book.getPublisher());
            stmt.setDouble(4, book.getPrice());
            stmt.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void deleteBook(int id) {
        try {
            PreparedStatement stmt = conn.prepareStatement("DELETE FROM books WHERE id = ?");
            stmt.setInt(1, id);
            stmt.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void updateBook(Book book) {
        try {
            PreparedStatement stmt = conn.prepareStatement("UPDATE books SET title = ?, author = ?, publisher = ?, price = ? WHERE id = ?");
            stmt.setString(1, book.getTitle());
            stmt.setString(2, book.getAuthor());
            stmt.setString(3, book.getPublisher());
            stmt.setDouble(4, book.getPrice());
            stmt.setInt(5, book.getId());
            stmt.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public Book getBookById(int id) {
        Book book = null;
        try {
            PreparedStatement stmt = conn.prepareStatement("SELECT * FROM books WHERE id = ?");
            stmt.setInt(1, id);
            ResultSet rs = stmt.executeQuery();
            if (rs.next()) {
                book = new Book();
                book.setId(rs.getInt("id"));
                book.setTitle(rs.getString("title"));
                book.setAuthor(rs.getString("author"));
                book.setPublisher(rs.getString("publisher"));
                book.setPrice(rs.getDouble("price"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return book;
    }
}

5. 创建Servlet类

我们需要创建一个Servlet类来处理HTTP请求，并将请求转发到相应的JSP页面。下面是一个简单的示例：

public class BookServlet extends HttpServlet {
    private BookDAO bookDAO = new BookDAO();

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String action = request.getServletPath();
        switch (action) {
            case "/new":
                showNewForm(request, response);
                break;
            case "/insert":
                insertBook(request, response);
                break;
            case "/delete":
                deleteBook(request, response);
                break;
            case "/edit":
                showEditForm(request, response);
                break;
            case "/update":
                updateBook(request, response);
                break;
            default:
                listBooks(request, response);
                break;
        }
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

    private void listBooks(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<Book> books = bookDAO.getAllBooks();
        request.setAttribute("books", books);
        RequestDispatcher dispatcher = request.getRequestDispatcher("book-list.jsp");
        dispatcher.forward(request, response);
    }

    private void showNewForm(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        RequestDispatcher dispatcher = request.getRequestDispatcher("book-form.jsp");
        dispatcher.forward(request, response);
    }

    private void insertBook(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String title = request.getParameter("title");
        String author = request.getParameter("author");
        String publisher = request.getParameter("publisher");
        double price = Double.parseDouble(request.getParameter("price"));
        Book book = new Book();
        book.setTitle(title);
        book.setAuthor(author);
        book.setPublisher(publisher);
        book.setPrice(price);
        bookDAO.addBook(book);
        response.sendRedirect("list");
    }

    private void deleteBook(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        bookDAO.deleteBook(id);
        response.sendRedirect("list");
    }

    private void showEditForm(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        Book book = bookDAO.getBookById(id);
        request.setAttribute("book", book);
        RequestDispatcher dispatcher = request.getRequestDispatcher("book-form.jsp");
        dispatcher.forward(request, response);
    }

    private void updateBook(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        String title = request.getParameter("title");
        String author = request.getParameter("author");
        String publisher = request.getParameter("publisher");
        double price = Double.parseDouble(request.getParameter("price"));
        Book book = new Book();
        book.setId(id);
        book.setTitle(title);
        book.setAuthor(author);
        book.setPublisher(publisher);
        book.setPrice(price);
        bookDAO.updateBook(book);
        response.sendRedirect("list");
    }
}

6. 创建JSP页面

最后，我们需要创建JSP页面来显示图书信息和处理用户输入。下面是一个简单的示例：

book-list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>图书列表</title>
</head>
<body>
    <h1>图书列表</h1>
    <table border="1">
        <tr>
            <th>ID</th>
            <th>标题</th>
            <th>作者</th>
            <th>出版社</th>
            <th>价格</th>
            <th>操作</th>
        </tr>
        <c:forEach var="book" items="${books}">
            <tr>
                <td>${book.id}</td>
                <td>${book.title}</td>
                <td>${book.author}</td>
                <td>${book.publisher}</td>
                <td>${book.price}</td>
                <td>
                    <a href="edit?id=${book.id}">编辑</a>
                    <a href="delete?id=${book.id}" onclick="return confirm('确定要删除该图书吗？')">删除</a>
                </td>
            </tr>
        </c:forEach>
    </table>
    <br>
    <a href="new">添加图书</a>
</body>
</html>

book-form.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>图书管理</title>
</head>
<body>
    <h1>图书管理</h1>
    <form action="${action}" method="post">
        <input type="hidden" name="id" value="${book.id}" />
        <label>标题：</label>
        <input type="text" name="title" value="${book.title}" /><br>
        <label>作者：</label>
        <input type="text" name="author" value="${book.author}" /><br>
        <label>出版社：</label>
        <input type="text" name="publisher" value="${book.publisher}" /><br>
        <label>价格：</label>
        <input type="text" name="price" value="${book.price}" /><br>
        <input type="submit" value="保存" />
    </form>
    <br>
    <a href="list">返回</a>
</body>
</html>

7. 配置Web.xml

最后，我们需要在Web.xml文件中配置Servlet。下面是一个简单的示例：

<servlet>
    <servlet-name>BookServlet</servlet-name>
    <servlet-class>com.example.BookServlet</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>BookServlet</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

现在，您可以在浏览器中打开http://localhost:8080/来访问该图书管理系统，并进行添加、删除、更新和查询等操作。