应用JDBC访问数据库 创建一个名为Books的数据库,并在其中建立一个名为book_message的表,字段包括书名、作者、出版社、出版时间和价格。编写一个应用程序,用预处理方式在该数据库中实现增加、删除和修改数据以及查

询所有书籍信息的功能。

首先需要安装并配置好JDBC驱动程序，然后编写Java代码来连接数据库。

创建数据库和表的SQL语句如下：

CREATE DATABASE Books;

USE Books;

CREATE TABLE book_message (
    id INT NOT NULL AUTO_INCREMENT,
    book_name VARCHAR(50) NOT NULL,
    author VARCHAR(50) NOT NULL,
    publisher VARCHAR(50) NOT NULL,
    publish_time DATE NOT NULL,
    price FLOAT NOT NULL,
    PRIMARY KEY (id)
);

然后，编写Java代码来实现增删改查功能，示例代码如下：

import java.sql.*;

public class BooksDB {
    private static final String URL = "jdbc:mysql://localhost:3306/Books";
    private static final String USER = "root";
    private static final String PASSWORD = "password";

    public static void main(String[] args) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;

        try {
            // 1. 连接数据库
            connection = DriverManager.getConnection(URL, USER, PASSWORD);

            // 2. 插入数据
            String insertSQL = "INSERT INTO book_message (book_name, author, publisher, publish_time, price) VALUES (?, ?, ?, ?, ?)";
            statement = connection.prepareStatement(insertSQL);
            statement.setString(1, "Java编程思想");
            statement.setString(2, "Bruce Eckel");
            statement.setString(3, "机械工业出版社");
            statement.setDate(4, Date.valueOf("2006-06-01"));
            statement.setFloat(5, 89.00f);
            statement.executeUpdate();

            // 3. 删除数据
            String deleteSQL = "DELETE FROM book_message WHERE book_name = ?";
            statement = connection.prepareStatement(deleteSQL);
            statement.setString(1, "Java编程思想");
            statement.executeUpdate();

            // 4. 修改数据
            String updateSQL = "UPDATE book_message SET price = ? WHERE book_name = ?";
            statement = connection.prepareStatement(updateSQL);
            statement.setFloat(1, 99.00f);
            statement.setString(2, "Head First Java");
            statement.executeUpdate();

            // 5. 查询数据
            String selectSQL = "SELECT * FROM book_message";
            statement = connection.prepareStatement(selectSQL);
            resultSet = statement.executeQuery();
            while (resultSet.next()) {
                System.out.println(resultSet.getInt("id") + "\t"
                        + resultSet.getString("book_name") + "\t"
                        + resultSet.getString("author") + "\t"
                        + resultSet.getString("publisher") + "\t"
                        + resultSet.getDate("publish_time") + "\t"
                        + resultSet.getFloat("price"));
            }

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            // 6. 关闭资源
            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (statement != null) {
                    statement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

这段代码使用了PreparedStatement来执行SQL语句，可以避免SQL注入攻击。同时，使用try-with-resources语句来自动关闭资源。