Iterate ArrayList in JSP

Question

I have two arraylists in my class and I want to send it to my JSP and then iterate the elements in arraylist in a select tag.

Here is my class:

package accessData;

import java.util.ArrayList;

public class ConnectingDatabase 
{
   ArrayList<String> food=new ArrayList<String>();
   food.add("mango");
   food.add("apple");
   food.add("grapes");

   ArrayList<String> food_Code=new ArrayList<String>();
   food.add("man");
   food.add("app");
   food.add("gra");
}

I want to iterate food_Code as options in select tag and food as values in Select tag in JSP; my JSP is:

<select id="food" name="fooditems">

// Don't know how to iterate

</select>

Any piece of code is highly appreciated. Thanks in Advance :)

Answer 1

You can use JSTL's foreach.

<c:forEach items="${foodItems}" var="item">
   ${item}
</c:forEach>

You need also to import JSTL core:

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

Answer 2

There are multiple ways this can be done (with some changes in your scheme)

Using JSTL:

1. Create a bean with two fields as food and food_code

   public class Food{ private String food; private String food_code; // Setter/getters follows }

Now the arraylist available on the page will be list Food objects. In the JSP code, you can use following:

<select name="fooditems">
    <c:forEach items="${list}" var="item">
        <option value="${item.food_code}">${item.food}</option>
    </c:forEach>
</select>

If you are using struts:

<html:select property="fooditems" >
<html:optionsCollection property="list" label="food" value="food_code" />
</html:select>

Here list is object key which will be used to retrieve the list from context (page/session)

Answer 3

It would be better to use a java.util.Map to store the key and values instead of two ArrayList, like:

Map<String, String> foods = new HashMap<String, String>();

// here key stores the food codes
// and values are that which will be visible to the user in the drop-down
foods.put("man", "mango");
foods.put("app", "apple");
foods.put("gra", "grapes");

// if this is your servlet or action class having access to HttpRequest object then
httpRequest.setAttribute("foods", foods); // so that you can retrieve in JSP

Now to iterate the map in the JSP use:

<select id="food" name="fooditems">
    <c:forEach items="${foods}" var="food">
        <option value="${food.key}">
            ${food.value}
        </option>
    </c:forEach>
</select>

Or without JSTL:

<select id="food" name="fooditems">

<%
Map<String, String> foods = (Map<String, String>) request.getAttribute("foods");

for(Entry<String, String> food : foods.entrySet()) {
%>

    <option value="<%=food.getKey()%>">
        <%=food.getValue() %>
    </option>

<%
}
%>

</select>

To know more about iterating with JSTL here is a good SO answer and here is a good tutorial about how to use JSTL in general.

Answer 4

<c:forEach items="${list}" var="foodItem">
 ${foodItem.propertyOfBean}
</c:forEach>

This will solve your problem.

Answer 5

You can retrieve the list in JSP as

<select id="food" name="fooditems">

  <c:forEach items="${listname}" var="food" >

     <option value="${food}"> ${food} </option>

  </c:forEach>

</select>