How to Iterate Through HashMaps in JSP Using JSTL and Avoid Scriptlets?

Looping Through HashMaps in JSP

Traversing a HashMap in JSP is similar to doing so in plain Java code. Utilize the following loop structure:

<pre class="brush:php;toolbar:false">String key = entry.getKey();
String value = entry.getValue();
// ...

}

Scriptlet Drawbacks

While scriptlets were previously common, they are now regarded as poor practice. Instead, we recommend using JSTL, which provides the tag for iterating over Maps, returning a Map.Entry object with getKey() and getValue() methods in each iteration.

<p><foreach items="${map}" var="entry"></foreach></p><pre class="brush:php;toolbar:false">Key = ${entry.key}, value = ${entry.value}<br>

JSP Solution

To resolve your specific problem:

<p><select name="country"></select></p><pre class="brush:php;toolbar:false"><foreach items='"${countries}"' var='"country"'>
    <option value='"${country.key}"'>${country.value}</option>
</foreach>

To make ${countries} accessible in the requested scope, use a Servlet or ServletContextListener.

Example Use Cases

Here are examples of using Servlet or ServletContextListener:

<pre class="brush:php;toolbar:false">Map<string string> countries = MainUtils.getCountries();
request.setAttribute("countries", countries);
request.getRequestDispatcher("/WEB-INF/page.jsp").forward(request, response);</string>

}

Or:

<pre class="brush:php;toolbar:false">Map<string string> countries = MainUtils.getCountries();
event.getServletContext().setAttribute("countries", countries);</string>

}

Further Reading

• Iterating Over Elements of Lists and Maps Using JSTL Tag


• Iterating Over a Nested Map in


• Iterating an ArrayList Inside a HashMap Using JSTL


• Using Special Auto Start Servlet to Initialize on Startup and Share Application Data

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