如何使用java servlet和jsp中的函数在数据库中插入值

Question

我正在尝试使用函数添加，更新和删除但未插入值。 请帮帮我。该值不会插入数据库，它会给出错误 保存记录后，不插入数据库值 我试过以下代码

package main;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

/**
 *
 * @author abc
 */
public class TenantOperation {

    private Connection conn;

    public TenantOperation()
    {
        conn = ConnectionDb.getConnection();
    }

    public void addTenant(TenantClass tenantclass) {
        try {
            String sql = "INSERT INTO tenantmaster(flatno,ownername,contactno,flattype,buildingname) VALUES (?, ?, ?, ?, ?)";
            PreparedStatement ps = conn.prepareStatement(sql);

            ps.setInt(1, tenantclass.getFlatno());
            ps.setString(2, tenantclass.getOwnername());
            ps.setString(3, tenantclass.getMob());            
            ps.setString(4, tenantclass.getFlattype());
            ps.setString(5, tenantclass.getBuildingname());
                    ps.executeUpdate();

        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

     public void removeTenant(int tenantId) {
        try {
            String sql = "DELETE FROM tenantmaster WHERE tenantid=?";
            PreparedStatement ps = conn
                    .prepareStatement(sql);
            ps.setInt(1, tenantId);
            ps.executeUpdate();

        } catch (SQLException e) {
            e.printStackTrace();
        }
      }


Here I have accessed that addtenant(). i have connect that function in this class


package main;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author abc
 */
public class TenantHandler extends HttpServlet {
     private static String insert= "/tenantadd.jsp";
    private static String Edit = "/tenantadd.jsp";
    private static String TenantRecords = "/tenantadd.jsp";
    private TenantOperation tenantOperation;

    public TenantHandler()
    {   
        super();
     tenantOperation = new TenantOperation();
    }



    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String redirect="";
        String flatno = request.getParameter("flatno");        
        String action = request.getParameter("action");

         if(action.equalsIgnoreCase("insert"))
        {   
            int no = Integer.parseInt(flatno);

            TenantClass tenantclass = new TenantClass();
            tenantclass.setFlatno(no);
            tenantclass.setOwnername(request.getParameter("ownername"));
             tenantclass.setMob(request.getParameter("mob"));
              tenantclass.setFlattype(request.getParameter("flattype"));
             tenantclass.setBuildingname(request.getParameter("buildingname"));


            tenantOperation.addTenant(tenantclass);
            redirect = TenantRecords;
               // request.setAttribute("tenantList", tenantOperation.getAllTenants());
            //System.out.println("Record Added Successfully");
        }


    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

    }  
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}