Question

在我的servlet中，我正在使用用户选择的产品并通过AJAX将产品ID传递给servlet

@WebServlet("/productSelected")
public class ProductCompareAJAX extends HttpServlet {

    private static final long serialVersionUID = 1L;

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    String productCode=request.getParameter("productCode");
    System.out.print("Product Code"+productCode);
    Set <String>prodCodeList=new HashSet<String>();
    prodCodeList.add(productCode);
    System.out.println(prodCodeList.toString());
    request.getSession().setAttribute("sessionProductCode", prodCodeList);
    System.out.println("Value in session *************"+request.getSession().getAttribute("sessionProductCode").toString());
    //String sessionProdId=request.getSession().getAttribute("sessionProductCode").toString();
    String nextJSP = "jsp/index.jsp";
    RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(nextJSP);
    dispatcher.forward(request,response);
    }

当用户从列表

中选择产品时，会触发此ajax调用

function addToCompare() {
    console.log("Product ID: "+ this.id);
    console.log("Product ID: "+ this.dataset.productId);
    var productCode;
   if($("input[id="+this.id+"]").is(':checked'))
       {

       //ajax call
       productCode=this.dataset.productId;
       alert(productCode);
       $.ajax({
           type: 'POST',
           url: 'productSelected',
           contentType: 'application/x-www-form-urlencoded; charset=UTF-8;',
           data: {productCode:"productCode"},
           cache: false,
           success: function (data) {
               alert("Success");
           }
         });

       // ajax call ends

       }
   else
       {
       alert("Not selected");
       }
}

$(function() {
    $('.productCheckbox').click(addToCompare);
    console.log("Document is ready");


});

//Output
Product Codenull[null]
Value in session *************[null]

请告诉我为什么我的servlet中的值为null。

Answer 1

在ajax数据选项中，您写为

data: {productCode:"productCode"},

因此productCode的值始终为 productCode 。

将其更改如下：

data: {productCode:productCode},

产品ID从ajax传递到servlet，但不知何故，值为null

1 个答案: