How to get array list size in java jsp?

Question

I have a form that ask for user to enter ID. This form is send to a servlet which checks database to see if user exist. If the user exists then it sends me back their ordere

Answer 1

ArrayList orderList = (ArrayList )  request.getAttribute("theOrder");

//Unchecked cast from Object to ArrayList 

Answer 2

you should set scope of your UserFound.jsp to request.

ArrayList orderList = (ArrayList )  request.getAttribute("theOrder");

<ul>
<% If(orderList  != null) {%>

   <% for(String orderName : orderList ) { %>
      <li> <%= orderName %> </li>
   <% } %>

<% }else{ %>
  No Order Found
<% } %>


</ul>

OR

ArrayList orderList = (ArrayList )  request.getAttribute("theOrder");
<ul>
<% If(orderList  != null) {%>

<% for(int orderNum =0;i< orderList.size();++orderNum  ) { %>
   <li> <%= orderList.get(orderNum )%> </li>
<% } %>
<% }else{ %>
  No Order Found
<% } %>
</ul>

Answer 3

Use fn:length function.

Declare fn namespace on the begining of the JSP file

<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>

Later in the code

${fn:length(collection)}

Answer 4

Newer versions of EL accept using the methods defined in the class of the object in EL expressions, so you can simply call the size() method:

<span>Size: ${list.size()}</span>