//SQL_Server:

String driver = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
String url = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=test";
String user = "sa";
String password = "";

//Oracle:

String driver = "oracle.jdbc.driver.OracleDriver";
String url = "jdbc:oracle:thin:@localhost:1521:wanchao";
String user = "scott";
String password = "tiger";

//mysql
String driver="com.mysql.jdbc.Driver";
String url="jdbc:mysql://localhost:3306/chinabank?useUnicode=true&characterEncoding=GBK";
String user="root";
String passeord="root";

Class.forName(driver);
con = DriverManager.getConnection(url,user,password);