从jsp页面onload事件仅调用一次servlet页面

Question

I have a jsp page in which I want to show 2 list to be populated using the values return by the servlet .this should happen as soon as the jsp page gets loaded so I called the servlet through the onload function of the jsp page . I am able to get the lists on the page but it went up to an infinite loop calling servlet again and again and displaying the same values.

In my test2.jsp,i am using this to call servlet on loading the jsp page

function load()
{

document.location.href="/OnaUIDemo/ona?";

}

in my ona servlet i am using this ,

RequestDispatcher rd = getServletContext().getRequestDispatcher("/test2.jsp");

what I figure out is that , because its calling the servlet through page load and also the servlet is redirecting to the same jsp. jsp is getting load again causing infinite load again and again. please help me to control the servlet call to only once.

Answer 1

Do you really need to use servlet?It can be done using POJO.

Make a class that will have that will return those two list.

public class test{

public List getList1()
{
//do your stuff here to add values in list
return list;//return your list 
}
public List getList2()
{
//do stuff here
return list;//return your list
}
}

In your jsp.Just call those two functions

<%
test t = new test();
List l1=t.getList1();
List l2=t.getList2();
//now you have the two list,just show them
%>

As scriptlets are discouraged as pointed out.You can use jstl

<jsp:useBean id="obj_name" type="package_name.class_name" />

this is equivalent to <%test t=new test();%> Now to iterate and show list values in jstl

<c:forEach var="content" items="${obj_name.list1}">
c:out value="${content}" />
</c:forEach>