The Api.java file

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.time.format.DateTimeFormatter;  
import java.time.LocalDateTime;    
import java.sql.*;
 
 
public class Api extends HttpServlet
{
 
 
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
      {
      response.setContentType("text/html");
      ServletOutputStream  out = response.getOutputStream();
      out.println("this is a get");
      String voltage = request.getParameter("voltage");
      out.println(voltage);
      System.out.println("GET : " + voltage);
 
 
      }
 
 
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
      {
	           Connection conn = null;
		   Statement stmt = null;
		   ResultSet rs = null;
 
      response.setContentType("text/html");
      ServletOutputStream  out = response.getOutputStream();
      out.println("This is a post \n");
      String voltage = request.getParameter("voltage");
      String key = request.getParameter("key");
      out.println(voltage);
      //Sql bla = new Sql();
 
      try {
 
 
               String userName = "xxxx";
               String passWord = "xxxx";
               String url = "jdbc:mysql://localhost/xxxxxxx";
               //Class.forName ("com.mysql.jdbc.Driver").newInstance();
               conn = DriverManager.getConnection (url, userName, passWord);
               System.out.println("Database connection established");
 
          }
          catch (SQLException e)
     {
     System.out.println("Cannot connect the database!" +  e.toString());
     }
 
 
 
      System.out.print("POST : " + voltage + "    ");
         DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy/MM/dd HH:mm:ss");  
	 LocalDateTime now = LocalDateTime.now();  
	 System.out.print(dtf.format(now));  
	 System.out.println("    " + key);
 
Sql bla = new Sql();
bla.runIt(voltage);
 
 
      }
 
 
}