Reading a table from database - glassfish

Question

I having a problem to run below Java code. I couldn't find the DB.java class.
ResultSet rs = DB.getConnection().createStatement().executeQuery("select * from products");
while(rs.next()){
System.out.print(rs.getString("pid"));
System.out.print(rs.getString("name"));
System.out.print(rs.getString("price"));
System.out.print(rs.getString("ava_qty"));
}
I'm using Glassfish server. Can someone help me to write the DB.java class?

Answer 1

The getConnection() method is part of the DriverManager class. Initialize your drivermanager properly, as described in this post:
https://www.tutorialspoint.com/javaexamples/jdbc_dbconnection.htm
Example code for future reference:
import java.sql.*;
public class jdbcConn {
public static void main(String[] args) {
try {
Class.forName("org.apache.derby.jdbc.ClientDriver");
} catch(ClassNotFoundException e) {
System.out.println("Class not found "+ e);
}
System.out.println("JDBC Class found");
int no_of_rows = 0;
try {
Connection con = DriverManager.getConnection (
"jdbc:derby://localhost:1527/testDb","username", "password");
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery ("SELECT * FROM employee");
while (rs.next()) {
no_of_rows++;
}
System.out.println("There are "+ no_of_rows + " record in the table");
} catch(SQLException e){
System.out.println("SQL exception occured" + e);
}
}
}