Servlet未将属性转发给JSP(JSP接收空)

Servlet

    ArrayList<String[]> itemsInCart = new ArrayList<String[]>();
    String[] test = {"bah","3.50","false"};
    itemsInCart.add(test);

    ArrayList<Integer> testALEmpty = new ArrayList<>();
    ArrayList<Integer> testALItems = new ArrayList<>();
    testALItems.add(1);
    testALItems.add(2);
    testALItems.add(3);


    String testStr = "This is a test string";

    request.setAttribute("testALEmpty", testALEmpty);
    request.setAttribute("testALItems", testALItems);

    request.setAttribute("testStr", testStr);

    request.setAttribute("cartAttribute", itemsInCart);


    try {
        getServletContext().getRequestDispatcher("/Cart.jsp").forward(request, response);
    } catch (Exception e) {
        e.printStackTrace();
    }

JSP

if (request.getAttribute("cartAttribute") == null) {
%>
<b>No Cart</b>
<%
}

当servlet转发到JSP时 无购物车 因为出于某种原因,servlet没有将属性传递给JSP。