Check if request.getParameter is null using JPS

Question

I don't know how to check if my parameter is null. How?

http://localhost:8080/msg?fn=Igor&sn=Jedna&id=2
http://localhost:8080/msg?p_r=null&fn=Igor&sn=Jedna&id=2

My code not working:

<% if (request.getParameter("p_r").equals("null")) {
    //do stuff with p_r
}
%>

AND

<% if (request.getParameter("p_r").equals(null)) {
    //do stuff with p_r
}
%>

org.apache.jasper.JasperException: An exception occurred processing JSP page

How can I check it?

[How to avoid Java code in JSP files](http://stackoverflow.com/questions/3177733/how-to-avoid-java-code-in-jsp-files) — Yassin Hajaj, Dec 12 '15 at 15:19

score 1 · Answer 1 · answered Dec 14 '15 at 10:41

1

First, check that param exists.

For example;

    <% 
        if(request.getQueryString().contains("p_r=")){
            if (request.getParameter("p_r").equals("null")) {
                out.print("p_r is null.");
             }
        }
    %>

answered Dec 14 '15 at 10:41

Gurkan Yesilyurt

2,635
2
20
21

score 0 · Answer 2 · answered Dec 12 '15 at 15:28

0

Try this:

<% if (request.getParameter("p_r") == null) {
       //it is null. do null-handling
   }
%>

answered Dec 12 '15 at 15:28

Alexey Malev

6,408
4
34
52

Check if request.getParameter is null using JPS

2 Answers2