Looping through response variables in a JSP

Question

I am writing a JSP page that retrieves variables from a servlet and outputs them to the user, my current code works as follows :

String uploadStatus = (String) request.getAttribute("uploadStatus");
String readStatus = (String) request.getAttribute("readStatus");
String saveStatus = (String) request.getAttribute("saveStatus");
String completeStatus = (String) request.getAttribute("completeStatus");
String applicationName = (String) request.getAttribute("applicationName"); 
String buildAndroid = (String) request.getAttribute("buildAndroid"); 
String buildWindows = (String) request.getAttribute("buildWindows"); 
String buildiOS = (String) request.getAttribute("buildiOS");
String uploadCompleteStatus = (String) request.getAttribute("uploadCompleteStatus"); 
String startBuild = (String) request.getAttribute("startBuild"); 
String finishBuild = (String) request.getAttribute("finishBuild"); 

out.println(uploadStatus + "<br>");
out.println(readStatus + "<br>");
out.println(saveStatus + "<br>");
out.println(applicationName + "<br>");
out.println(buildAndroid + "<br>");
out.println(buildWindows + "<br>");
out.println(buildiOS + "<br>");
out.println(uploadCompleteStatus + "<br>");
out.println(startBuild + "<br>");
out.println(finishBuild + "<br>");

It works perfectly, but the code is lengthy and not very expnadable. I am wondering if their is a way to do this simpler in the JSP with a for loop and possibly a wildcard character. Anybody have any ideas?

Thanks

c.P.u1 · Accepted Answer · 2013-08-08T10:36:45.877

4

Why don't you add all status variables to a List<String> and add the List to a request attribute? This way you can use a single loop to output all variables.

List<String> statusItems = new ArrayList<>();
statusItems.add(uploadStatus);
statusItems.add(readStatus);
...
request.setAttribute("statusItems", statusItems);

BTW, the use of scriptlets in JSPs is discouraged. Use JSTL:

<c:forEach var="status" items="${requestScope.statusItems}">
  ${status} <br/>
</c:forEach>

Or use <c:out value="${status}"/> within forEach if you want your status values to be HTML-escaped.

edited Aug 08 '13 at 10:36

answered Aug 08 '13 at 10:23

c.P.u1

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Or just `${statusItems}` – Rohit Jain Aug 08 '13 at 10:28
I have never used JSTL, is it a library I have to download? – MattTheHack Aug 08 '13 at 10:41
Yes, it is a tag library. Please refer this post for more information on JSTL: http://stackoverflow.com/questions/3177733/how-to-avoid-java-code-in-jsp-files/3180202#3180202 – c.P.u1 Aug 08 '13 at 10:44

score 3 · Answer 2 · answered Aug 08 '13 at 10:25

3

Make use the req.getAttributeNames()

    Enumeration attrs =  req.getAttributeNames();
    while(attrs.hasMoreElements()) {
        String val = (String) req.getAttribute((String) attrs.nextElement());
        System.out.println(val);
    }

answered Aug 08 '13 at 10:25

Suresh Atta

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Java Code in JSP - No No!! – Rohit Jain Aug 08 '13 at 10:26
1

@RohitJain This code work's(Atleast helps) If OP wants to prepare List in servlet and pass to the JSP.And NO NO to java code in JSP too :) – Suresh Atta Aug 08 '13 at 10:28

score 1 · Answer 3 · answered Aug 08 '13 at 10:25

1

Sure try this:

for (String lAttributeName : request.getAttributeNames()){
       System.out.println((String)request.getAttribute(lAttributeName));
}

answered Aug 08 '13 at 10:25

nano_nano

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Looping through response variables in a JSP

3 Answers3