servlet, mysql JDBC connection and Parameters

[induz sat]

I want to have multiple JDBC-connections (to mySQL databse) in my servlet.

For each servlet I use:

database connection settings
final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
final String dbURL = "jdbc:mysql://localhost:3306/SocialNetwork";
final String dbUser = "root";
final String dbPass = "root";
Connection conn = null;
//*************************************************************		

		try {

			// Register JDBC driver
			Class.forName(JDBC_DRIVER);
//***************************************************************
// DriverManager methods for connection to mySQL server

System.out.println("Connecting to a selected database...");

conn = DriverManager.getConnection(dbURL, dbUser, dbPass);
					


System.out.println("Connected database successfully...");
//***************************************************************
			
System.out.println("Connecting to a selected database...");
 

After establishing JDBC connection to SocialNetwork DataBase, I use insert, and update queries to add/update the records on my userInfo db.

PreparedStatement updateUserInfo = (PreparedStatement) conn
					.prepareStatement("insert into userInfo WHERE ( UserName, userPW) values(?,?)");
	
						updateUserInfo.executeUpdate();

i want the same JDBC connection to use in another servlet[userLogin] in the same application/package.

Is there a way I can create another connection servler/class and import it and use it in all other Httpservlets responsible for registering a new user , checking records, updating records etc..in the same SocialNetwork Db but different tables??

The 'UserLogin' servlet checks two records userName and Password in 'registredUser' table when the user logs-in through a login.jsp page with userName and password.

I am getting input parameters onto the UserLogin servlet from Login.jsp as below

String user = req.getParameter("loginName");
		String pw = req.getParameter("loginPW");

How should i go about checking name and password in terms of sql queries- right now I am trying to use

String sql = "SELECT userName "
                + "FROM userInfo "
                + "WHERE userPass=?";
   connection = ConnectionFactory.getConnection();
  ptmt = (PreparedStatement) connection.prepareStatement(sql);
  
       
			ptmt.setString(1, user);
			  resultSet = ptmt.executeQuery();

to make it clear I have 2 tables[ registredUser and UserInfo.
RegistredUser has these colums- UserId, userName, Password, Age and city. user Id is PK and AI.

UserInfo has userId, userName and Password. User Id is PK and AI in this table too.

How can i establish a relation between userID in two different tables and check/authenticate the userName and password??

[Ivan Jozsef Balazs]

Some side notes:

Database connections in servlet environments are best used through connection pools.

Hardwiring the database parameters into the source code is not good.