第一种：直接创建driver对象

//1、注册驱动
Driver driver = new Driver();//创建driver对象

//2、得到连接
String url = "jdbc:mysql://localhost:3306/books?serverTimezone=UTC";

//将用户名和密码放入Properties对象
Properties properties = new Properties();
properties.setProperty("user","root");
properties.setProperty("password","123456");

Connection connect = driver.connect(url, properties);//进行连接

第二种：利用反射获取driver对象

//1、注册驱动
//利用反射加载driver类
Class<?> aClass = Class.forName("com.mysql.cj.jdbc.Driver");
Driver driver = (Driver)aClass.newInstance();

//2、得到连接
String url = "jdbc:mysql://localhost:3306/books?serverTimezone=UTC";

//将用户名和密码放入Properties对象
Properties properties = new Properties();
properties.setProperty("user","root");
properties.setProperty("password","123456");

Connection connect = driver.connect(url, properties);//进行连接

第三种：使用DriverManager注册驱动

//1、注册驱动
//利用反射加载driver类
Class<?> aClass = Class.forName("com.mysql.cj.jdbc.Driver");
Driver driver = (Driver)aClass.newInstance();

//2、得到连接
String url = "jdbc:mysql://localhost:3306/books?serverTimezone=UTC";

//将用户名和密码放入Properties对象
Properties properties = new Properties();
properties.setProperty("user","root");
properties.setProperty("password","123456");

DriverManager.registerDriver(driver);//注册driver驱动

Connection connect = DriverManager.getConnection(url, properties);//进行连接

第四种：不需要创建driver对象，在反射加载完成后，就可以直接调用静态方法建立连接

//1、注册驱动
//利用反射加载driver类
//在加载过程中就完成了driver类的注册
Class.forName("com.mysql.cj.jdbc.Driver");

//2、得到连接
String url = "jdbc:mysql://localhost:3306/books?serverTimezone=UTC";

//将用户名和密码放入Properties对象
Properties properties = new Properties();
properties.setProperty("user","root");
properties.setProperty("password","123456");
//不需要注册驱动就可以直接调用静态方法

Connection connect = DriverManager.getConnection(url, properties);//进行连接

（推荐）第五种：将必要信息放入配置文件中，通过加载配置文件，得到所有信息

//获取配置文件中的信息
Properties properties = new Properties();
properties.load(new FileInputStream("src\\mysql.properties"));
String root = properties.getProperty("user");
String password = properties.getProperty("password");
String url = properties.getProperty("url");
String driver = properties.getProperty("driver");

//注册驱动
Class.forName(driver);

//建立连接
Connection connection = DriverManager.getConnection(url, root, password);