java jsp file update table field in database

Question

I am trying to update the number of trips done by employees.
In the table below, I get the list of the employees and the number of trips done by each, and an input field to update that number. However, I get

error 500 null

.

Could somebody help me to resolve this issue? thanks a lot.

inside Controller.java

        public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {



    ....



            } else if (methode.equals("post") && action.equals("/updateemployees")) {

                doUpdateEmployee(request, response);

    ....





        private void doUpdateEmployee(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {





                int tripsInitialvalue = Integer.valueOf(request.getParameter("nbTrips"));

[line: 177]     int id = Integer.valueOf(request.getParameter("id"));





                EmployeeDAO.addTrips(id,tripsInitialvalue);





                doEmployees(request, response);



            }

inside my EmployeeDAO.java

public static Employee addTrips(int id, int tripsToAdd) {

        EntityManager em = GestionFactory.factory.createEntityManager();

        Employee employee = em.find(Employee.class, id);

        em.getTransaction().begin();

        int tripsInitialvalue = employee.getNbTrips();

        employee.setNbTrips(tripsInitialvalue + tripsToAdd);

        em.getTransaction().commit();

        em.close();

        return employee;

    }

and my employees.jsp file:

<form method="post" action="<%= getServletContext().getContextPath()%>/do/updateemployees">  

<table>

    <tr>

        <th>Employee ID</th>

        <th>Name</th>

        <th>Number of Trips</th>        

        <th>Edit Trips</th>

    <tr>

<% for (Employee employee : employees) {%>

    <tr>

        <td><%=employee.getId()%></td>

        <td><%=employee.getName()%></td>        

        <td><%=employee.getNbTrips()%></td>     

        <td><input type="number" name="nbTrips" size="2" value="<%=employee.getNbTrips()%>"></td>

    </tr>

<% } %>

</table>

<input type="submit" value="Update"/>

</form>

error log:

Etat HTTP 500 - null

message null

java.lang.NumberFormatException: null

    java.lang.Integer.parseInt(Unknown Source)

    java.lang.Integer.valueOf(Unknown Source)

    projet.controleur.Controleur.doUpdateEmployee(Controller.java:177)

    projet.controleur.Controleur.doGet(Controller.java:109)

    projet.controleur.Controleur.doPost(Controller.java:69)

    javax.servlet.http.HttpServlet.service(HttpServlet.java:648)

    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

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Answer 1

so from the error details it is apparent that the valueOf is trying to parse null in the code.you cannot parse a "null" to int.

if(request.getParameter("id") != null) {

int id = Integer.valueOf(request.getParameter("id"));
EmployeeDAO.addTrips(id,tripsInitialvalue);

} else {
  //decide what to do when id is null
}

EDIT : To get values of all textboxes use request.getParameterValues('nbTrips'), this will return all the values for elements with same 'nbTrips'

String[] nbTrips = request.getPrameterValues('nbTrips')

will return all the text box values with name 'nbTrips' into String array nbTrips which you can iterate and get each values from textBox.

java jsp file update table field in database

error log:

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