獲取Connection的5種方式

 //方式一
 @Test
 public void test1() throws SQLException {
  //獲取Driver實現類對象
  Driver driver = new Driver();
  //jdbc:mysql 協議
  //localhost：ip地址
  //zoo 數據庫名
  String url = "jdbc:mysql://localhost:3306/zoo?serverTimezone=UTC";  
  //將用戶名和密碼封裝在properties中
  Properties info = new Properties();
  info.setProperty("user", "root");
  info.setProperty("password", "root");
  
  Connection conn=driver.connect(url, info);
  System.out.println(conn);
 }

//方式2:在如下的程序中，不出先第三方的API，有可移植性
 @Test
 public void test2() throws Exception {
  //使用反射獲取Driver對象              com.mysql.cj.jdbc.Driver
  Class clazz = Class.forName("com.mysql.cj.jdbc.Driver");
  Driver driver = (Driver) clazz.newInstance();
  
  //提供連接的數據庫
  String url="jdbc:mysql://localhost:3306/zoo?serverTimezone=UTC";
  //提供需要的用戶名和密碼
  Properties info=new Properties();
  info.setProperty("user", "root");
  info.setProperty("password", "root");
  
  Connection conn=driver.connect(url, info);
  System.out.println(conn);
 }

//方式3：使用DriverManager替換Driver
 @Test
 public void test3() throws Exception {
  //獲取Driver實現類對象
  Class clazz = Class.forName("com.mysql.cj.jdbc.Driver");
  Driver driver =(Driver) clazz.newInstance();
  
  //注冊驅動
  DriverManager.registerDriver(driver);
  
  String url="jdbc:mysql://localhost:3306/zoo?serverTimezone=UTC";
  //獲取連接
  Connection connection = DriverManager.getConnection(url, "root", "root");
  System.out.println(connection);
 }

//方式4：可以知識加載驅動，不要顯示注冊驅動了
 @Test
 public void test4() throws Exception {
  Class.forName("com.mysql.cj.jdbc.Driver");
  String url="jdbc:mysql://localhost:3306/zoo?serverTimezone=UTC";
  Connection connection = DriverManager.getConnection(url, "root", "root");
  System.out.println(connection);
 }
 
 @Test
 public void test5() throws Exception {
  Class.forName("com.mysql.cj.jdbc.Driver");
  Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306?serverTimezone=UTC", "root", "root");
  System.out.println(connection);
 }

//方式5：將數據庫連接需要的4個基本信息聲明在配置文件中
 @Test
 public void test6() throws Exception {
  //讀取配置文件中的基本信息
  InputStream is = ConnectionTest.class.getClassLoader().getResourceAsStream("jdbc.properties");
  Properties properties = new Properties();
  properties.load(is);
  
  String user = properties.getProperty("user");
  String password = properties.getProperty("password");
  String url = properties.getProperty("url");
  String DrverClass = properties.getProperty("DrverClass");
  
  Class.forName(DrverClass);
  Connection connection = DriverManager.getConnection(url, user, password);
  System.out.println(connection);
 }

 轉載:https://blog.csdn.net/weixin_45371966/article/details/103549042