为什么会出现错误“方法...类型未定义...”？

Question

I've build a method which takes strings as input parameter. In my index.jsp page, I retrieve a GET-variable from the URL using request.getParameter() . Now, I want to call the aforementioned method on this string, but I get a compiler error saying:

The method <method name> (String) is undefined for the type __2F_<webapp name>_2F_src_2F_main_2F_webapp_2F_index_2E_jsp ".

Does anyone know why I get this error and how I can get rid of it. Any help is greatly appreciated!

My code is rather lengthy, but I think this is relevant code:

categorie = request.getParameter("categorie");

if (categorie.equals("")) {
    categorie = "Category;";
}

ArrayList<String> categorieen = queryCategories(categorie);

Answer 1

You are calling ArrayList<String> categorieen = queryCategories(categorie); and you did not define queryCategories method. Since the JSP page is compiled into a big servlet class, it tries to locate queryCategories method as member of that class and it could not find it.

Answer 2

Very little information. Where is your app deployed? From what I gather, it seems you either haven't restarted the deployed app or have not replaced the changed class file and haven't set some sort of "development mode" on wherein you don't require a restart for a Jsp modification.

Just replace the .jsp and JSP_NAME.class file.