java 与mysql连接包

try {
    // 加载驱动程序
    Class.forName("com.mysql.cj.jdbc.Driver");
    
    // 建立连接
    String url = "jdbc:mysql://hostname:port/database";
    String user = "username";
    String password = "password";
    Connection conn = DriverManager.getConnection(url, user, password);
} catch (ClassNotFoundException e) {
    e.printStackTrace();
} catch (SQLException e) {
    e.printStackTrace();
}

String sql = "SELECT * FROM users WHERE username = ?";
try (Connection conn = DriverManager.getConnection(url, user, password);
     PreparedStatement pstmt = conn.prepareStatement(sql)) {
    pstmt.setString(1, username);
    ResultSet rs = pstmt.executeQuery();
    // 处理结果集
} catch (SQLException e) {
    e.printStackTrace();
}

try (Connection conn = DriverManager.getConnection(url, user, password);
     Statement stmt = conn.createStatement();
     ResultSet rs = stmt.executeQuery("SELECT * FROM table")) {
    // 处理结果集
} catch (SQLException e) {
    e.printStackTrace();
}

import java.sql.*;

public class MySQLConnectionExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String user = "root";
        String password = "mypassword";

        try {
            // 加载MySQL JDBC驱动程序
            Class.forName("com.mysql.cj.jdbc.Driver");

            // 建立连接
            Connection conn = DriverManager.getConnection(url, user, password);

            // 创建Statement对象
            Statement stmt = conn.createStatement();

            // 执行查询
            ResultSet rs = stmt.executeQuery("SELECT * FROM users");

            // 处理结果集
            while (rs.next()) {
                System.out.println(rs.getString("username"));
            }

            // 关闭资源
            rs.close();
            stmt.close();
            conn.close();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}