Servlets, JPA, JSP - Servlet don't work correctly

Question

I don't know why my servlet doesn't work. My code bellow:

userOrdersServlet.java

@WebServlet("/userOrders")
public class userOrdersServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        HttpSession session = request.getSession();
        int userId = (int) session.getAttribute("userId");
        UserDAO daoUser = (UserDAO) request.getAttribute("userDao");
        User user = daoUser.getUser(userId);
        List<Books> booksOrderedByUser = user.getBooks();
        request.setAttribute("booksOrderedByUser", booksOrderedByUser);
        request.getRequestDispatcher("/userOrders.jsp").forward(request, response);

    }

}

userDAO.java

public User getUser(int id) {
        this.em.clear();
        return this.em.find(User.class, id);
    }

userOrders.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> 
<!DOCTYPE html>
<html>
<head>
<link href="style.css" rel="stylesheet" type="text/css" />
<title>Library Online</title>
</head>
<body>
<div id="container">
    <%@include  file="templateTop.jsp" %>
<div class="main"><table border="1">
    <h2>Your orders</h2>
            <tr>
                <td>Title</td>
                <td>Author</td>
                <td>Description</td>
                <td>Category</td>
                <td>Year</td>
            </tr>
            <c:forEach var="booksOrdered" items="${booksOrderedByUser}">
                <tr>
                    <td>${booksOrdered.title}</td>
                    <td>${booksOrdered.author}</td>
                    <td>${booksOrdered.description}</td>
                    <td>${booksOrdered.category}</td>
                    <td>${booksOrdered.year}</td>
                    </tr>
            </c:forEach>
            </table>
    </div>
                    </div>
            <div style="clear:both"></div>

    <br>


</body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>RegisterLoginJPA</display-name>
<welcome-file-list>
<welcome-file>/index.jsp</welcome-file>
</welcome-file-list>
<filter>
<filter-name>sessionFilter</filter-name>
<filter-class>filters.sessionFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>sessionFilter</filter-name>
<url-pattern>/loginSuccess.jsp</url-pattern>
<dispatcher>REQUEST</dispatcher>
</filter-mapping>
</web-app>

So I used code from userOrdersServlet.javaand display data using foreach loop and System.out.println() in another servlet and it works correctly. But when I go to userOrders.jsp it doesn't show any data, What I did wrong?

Post your web.xml and the rest of your userOrder.jsp please. What error are you facing also? — Perdomoff, Dec 07 '15 at 19:27
I didn't notice any error, every other servlet works well, i put simple redirect to doGet method in this servlet and still don't work. — Kamil W, Dec 07 '15 at 19:46
What are you trying to accomplish? What is your expected output? — Perdomoff, Dec 07 '15 at 19:50
I want to display on userOrders.jsp books ordered by user using expresion language but when i go to this page it's only shows me blank table, but as i wrote i display i'm using another servlet to display results via `System.out.println()` it works pretty well — Kamil W, Dec 07 '15 at 19:57
is this line returning the values you're expecting: List booksOrderedByUser = user.getBooks(); — Perdomoff, Dec 07 '15 at 20:02
I think maybe this: items="${booksOrderedByUser}"> should be items="${param.booksOrderedByUser}"> — mmulholl, Dec 07 '15 at 20:49
Wrap this around your loop in your jsp to see if the list is empty or not: }"> ... — Perdomoff, Dec 07 '15 at 20:54
What happens if you change the link to Orders i.e. map the link to the Servlet which then forwards to the JSP. — Alan Hay, Dec 08 '15 at 13:42
@AlanHay Thanks, that fix my problem, but i using doGet method how can I change it to doPost? — Kamil W, Dec 08 '15 at 18:28
Just override the doGet() method in the servlet and call doPost(request, response) from within. — Alan Hay, Dec 08 '15 at 18:41

score 0 · Answer 1 · edited May 23 '17 at 12:23

0

To access a request parameter in a JSP you need to precede the parameter name with "param." So

<c:forEach var="booksOrdered" items="${booksOrderedByUser}">

should be:

<c:forEach var="booksOrdered" items="${param.booksOrderedByUser}">

see: JSP Expression Language get parameter

edited May 23 '17 at 12:23

Community

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answered Dec 07 '15 at 20:59

mmulholl

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Servlets, JPA, JSP - Servlet don't work correctly

1 Answers1