【大数据系列之JDBC】（三）：Java获取数据库连接的5种方式

// 1.获取Driver对象
Driver driver = new com.mysql.jdbc.Driver();
// 2.提供要连接的数据库
String url = "jdbc:mysql://localhost:3306/test";
// 3.提供连接需要的用户名和密码
Properties info = new Properties();
info.setProperty("user", "root");
info.setProperty("password", "123456");
// 4.获取连接
Connection conn = driver.connect(url, info);
System.out.println(conn);

// 1.通过反射获取Driver对象
Class clazz = Class.forName("com.mysql.jdbc.Driver");
Driver driver = (Driver) clazz.newInstance();
// 2.提供要连接的数据库
String url = "jdbc:mysql://localhost:3306/test";
// 3.提供连接需要的用户名和密码
Properties info = new Properties();
info.setProperty("user", "root");
info.setProperty("password", "123456");
// 4.获取连接
Connection conn = driver.connect(url, info);
System.out.println(conn);

// 1.通过反射获取Driver对象
Class clazz = Class.forName("com.mysql.jdbc.Driver");
Driver driver = (Driver) clazz.newInstance();
// 2.提供连接的基本信息
String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "123456";
// 3.注册驱动
DriverManager.registerDriver(driver);
// 4.获取连接
Connection conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);

// 1.通过反射获取Driver对象
Class clazz = Class.forName("com.mysql.jdbc.Driver");
// 2.提供连接的基本信息
String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "123456";
// 3.获取连接
Connection conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);

// 1.读取配置文件
InputStream is = Main.class.getClassLoader().getResourceAsStream("jdbc.properties");
Properties pros = new Properties();
pros.load(is);
String user = pros.getProperty("user");
String password = pros.getProperty("password");
String url = pros.getProperty("url");
String driverClass = pros.getProperty("driverClass");
// 2.加载驱动
Class.forName(driverClass);
// 3.获取连接
Connection conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);

user=root
password=123456
url=jdbc:mysql://localhost:3306/test
driverClass=com.mysql.jdbc.Driver