maven怎么实现数据库增删改查

要使用Maven实现数据库增删改查功能，您需要在Maven项目中添加数据库驱动依赖，然后编写数据库操作的代码。以下是一个简单的示例：

1、添加mysql数据库驱动依赖到pom.xml文件中：

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.26</version>
</dependency>

2、编写数据库操作的Java代码：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DatabaseOperations {

    private static final String URL = "jdbc:mysql://localhost:3306/mydatabase";
    private static final String USER = "username";
    private static final String PASSWORD = "password";

    public void insertData(String name, String email) {
        try (Connection conn = DriverManager.getConnection(URL, USER, PASSWORD)) {
            String sql = "INSERT INTO users (name, email) VALUES (?, ?)";
            try (PreparedStatement stmt = conn.prepareStatement(sql)) {
                stmt.setString(1, name);
                stmt.setString(2, email);
                stmt.executeUpdate();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void updateData(int id, String email) {
        try (Connection conn = DriverManager.getConnection(URL, USER, PASSWORD)) {
            String sql = "UPDATE users SET email = ? WHERE id = ?";
            try (PreparedStatement stmt = conn.prepareStatement(sql)) {
                stmt.setString(1, email);
                stmt.setInt(2, id);
                stmt.executeUpdate();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void deleteData(int id) {
        try (Connection conn = DriverManager.getConnection(URL, USER, PASSWORD)) {
            String sql = "DELETE FROM users WHERE id = ?";
            try (PreparedStatement stmt = conn.prepareStatement(sql)) {
                stmt.setInt(1, id);
                stmt.executeUpdate();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void queryData() {
        try (Connection conn = DriverManager.getConnection(URL, USER, PASSWORD)) {
            String sql = "SELECT * FROM users";
            try (PreparedStatement stmt = conn.prepareStatement(sql);
                 ResultSet rs = stmt.executeQuery()) {
                while (rs.next()) {
                    int id = rs.getInt("id");
                    String name = rs.getString("name");
                    String email = rs.getString("email");
                    System.out.println("ID: " + id + ", Name: " + name + ", Email: " + email);
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        DatabaseOperations db = new DatabaseOperations();
        db.insertData("Alice", "alice@example.com");
        db.updateData(1, "alice.new@example.com");
        db.deleteData(1);
        db.queryData();
    }
}

这个示例代码演示了如何使用Maven项目实现数据库的增删改查功能。您需要根据自己的数据库连接信息修改URL、USER和PASSWORD参数，然后通过调用不同的方法实现相应的数据库操作。在main方法中，我们创建了DatabaseOperations对象并调用了insertData、updateData、deleteData和queryData方法来执行相应的数据库操作。