Three database default port

The default port 1.Oracle database: 1521

Url:"jdbc:oracle:thin:@localhost :1521:orcl";

DriverName:"oracle.jdbc.driver.OracleDriver";

The default port 2.MySQL database: 3306

Url:jdbc:mysql://localhost:3306/test? user=root&password=xxxxx; （MySQL5系列）

DriverName:"com.mysql.jdbc.Driver";

Url:jdbc:mysql://localhost:3306/test? user=root&password=xxxxx&serverTimezone=UTC&characterEncoding=utf-8&useSSL=false; （MySQL8系列）

DriverName:"com.mysql.cj.jdbc.Driver";

3. The default port number for the database sqlserver: 1433

URL:"jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=dbname"；

DriverName:"com.microsoft.jdbc.sqlserver.SQLServerDriver";