MVC CODE FOR ANDROID REQUEST AND RESPONSE -Programming Logic and Code with Syntax Dizsweb

package com.sawan;

import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Enumeration;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONObject;
@WebServlet("/DirectorStudentList")
public class DirectorStudentList extends HttpServlet {
 private static final long serialVersionUID = 1L;
 Statement stmt = null; 
  
    public DirectorStudentList() {
        super();
        // TODO Auto-generated constructor stub
    }

 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    JSONObject json = new JSONObject();  
    Enumeration paramNames = request.getParameterNames();
         String params[] = new String[3];
         int i = 0;
         while (paramNames.hasMoreElements())
         {
             String paramName = (String) paramNames.nextElement();
          System.out.println(".........params[]....................."+paramName);
             System.out.println(paramName);
             String[] paramValues = request.getParameterValues(paramName);
             params[i] = paramValues[0];
          System.out.println(".............+params[i]................."+params[i]);
          System.out.println(".............+params[i]................."+params[i]);
             System.out.println(params[i]);
             i++;
         }
         ResultSet rs=null;
         String table=params[1]; 
         String cutoff=params[0];
         DataBase  db=new DataBase();
         Connection con=db.getConnection();
         table=table;
         String Roll=params[0];
         int code=Integer.parseInt(params[0]);
         System.out.println("rOLL nO............"+Roll);
         String sql="SELECT * FROM Attendance."+table+"  WHERE STUDENTBRANCH ="+code+" AND STUDENTSECTION='"+params[2]+"'"; 
         System.out.println(sql);
         try {    stmt=con.createStatement();
         rs = stmt.executeQuery(sql); 
   } catch (SQLException e1) {

    e1.printStackTrace();
   }
         
         try {
          System.out.println("STEMENT EXECUTE..............");
          System.out.println("RESULT SET EXECUTR..............");
          int u=0;
          int s=0;
          
          while (rs.next()) {
               json.put("name"+s,rs.getString("STUDENTNAME"));
               json.put("roll"+s,rs.getString("STUDENTROLL"));
               json.put("info", "success"); 
              s++;
              json.put("row",s);
                  System.out.println("RESULT SET EXECUTR.......2.......");
                 u=1; 
              }
              if(u==0)
              {
                 json.put("info", "fail");
              }
          
              System.out.println("RESULT SET EXECUTR.........24.....");
         } catch (Exception e) {
             e.printStackTrace();
         }
      
         System.out.println(json);
         response.setContentType("application/json");
         response.setCharacterEncoding("UTF-8");
         response.getWriter().write(json.toString());
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {


}
}