Check a collection size with JSTL

length( java.lang.Object) - Returns the number of items in a collection, or the number of characters in a string.

put this at the top of the page to allow the fn namespace

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

and use like this in your jsp page

<p>The length of the companies collection is : ${fn:length(companies)}</p>

(from memory)

So to test with length of a collection:

<c:if test="${fn:length(companies) gt 0}">
   <p>It is greater than 0</p>
</c:if>

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How to iterate HashMap using JSTL forEach loop

Iterate a List

//Java

List<String> cityList = new ArrayList<String>();

cityList.add("Washington DC");

cityList.add("Delhi");

cityList.add("Berlin");

cityList.add("Paris");

cityList.add("Rome");

 

request.setAttribute("cityList", cityList);

 

 

//JSP

<c:forEach var="city" items="cityList">

    <b> ${city} </b>

</c:forEach>




Iterate a Hashmap

//Java Map<String, String> countryCapitalList = new HashMap<String, String>(); countryCapitalList.put("United States", "Washington DC"); countryCapitalList.put("India", "Delhi"); countryCapitalList.put("Germany", "Berlin"); countryCapitalList.put("France", "Paris"); countryCapitalList.put("Italy", "Rome");           request.setAttribute("capitalList", countryCapitalList);   //JSP <c:forEach var="country" items="${capitalList}">     Country: ${country.key}  - Capital: ${country.value} </c:forEach>

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