idea连接数据库五种方式

连接数据库的五种方式

方式一

public void testConnection() throws SQLException {
        Driver driver=new com.mysql.cj.jdbc.Driver();
        //tset指数据库名，根据名字不同改，3306为端口号
        String url="jdbc:mysql://localhost:3306/test?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC";
        //将用户名和密码封装
        Properties into=new Properties();
          //用户名和密码需根据你所设置的填写
        into.setProperty("user","用户名");
        into.setProperty("password","密码");

        Connection connect = driver.connect(url, into);

        System.out.println(connect);

    }

方式二

public void test2() throws ClassNotFoundException, IllegalAccessException, InstantiationException, SQLException {
        //获取Driver实例化对象，使用反射
        Class aClass = Class.forName("com.mysql.cj.jdbc.Driver");
        Driver driver= (Driver) aClass.newInstance();
        //提供连接数据库
        String url="jdbc:mysql://localhost:3306/test?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC";
        //提供用户名，密码
        Properties into=new Properties();
        into.setProperty("user","用户名");
        into.setProperty("password","密码");
        //获取连接
        Connection connect = driver.connect(url, into);
        System.out.println(connect);

    }

方式三

public void test3() throws ClassNotFoundException, IllegalAccessException, InstantiationException, SQLException {
        Class aClass = Class.forName("com.mysql.cj.jdbc.Driver");
        Driver driver= (Driver) aClass.newInstance();
        //基本信息
        String url="jdbc:mysql://localhost:3306/test?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC";
        String user="用户名";
        String password="密码";

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

        //获取连接
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);
    }

方式四

public void test4() throws ClassNotFoundException, SQLException, IllegalAccessException, InstantiationException {
        //基本信息
        String url="jdbc:mysql://localhost:3306/test?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC";
        String user="用户名";
        String password="密码";

        //加载Driver驱动
       Class.forName("com.mysql.cj.jdbc.Driver");
   

        //获取连接
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);

    }

方式五（推荐使用这种方式连接数据库）

user=数据库用户名
password=数据库密码
url=jdbc:mysql://localhost:3306/数据库表名?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC
driverClass=com.mysql.cj.jdbc.Driver

public void test5() throws IOException, ClassNotFoundException, SQLException {
        //读取配置文件基本信息，jdbc。properties为文件名，根据不同命名修改
        InputStream resourceAsStream = DriverConnect.class.getClassLoader().getResourceAsStream("jdbc.properties");

        Properties properties = new Properties();
        properties.load(resourceAsStream);

        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String url= properties.getProperty("url");
        String driverClass= properties.getProperty("driverClass");

        //加载驱动
        Class.forName(driverClass);

        //获取连接
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);

    }