Selected value for JSP drop down using JSTL

问题

I have SortedMap in Servlet to populate drop down values in JSP and I have the following code

    SortedMap<String, String> dept = findDepartment();
    request.setAttribute(\"dept \", dept);

and in JSP

       <select name=\"department\">
          <c:forEach var=\"item\" items=\"${dept}\">
            <option value=\"${item.key}\">${item.value}</option>
          </c:forEach>
        </select>

I am using one JSP page for insert and update. When I am editing the page how can I set selected value to drop down where selected value will come from database.

回答1:

In HTML, the selected option is represented by the presence of the selected attribute on the <option> element like so:

<option ... selected>...</option>

Or if you're HTML/XHTML strict:

<option ... selected="selected">...</option>

Thus, you just have to let JSP/EL print it conditionally. Provided that you've prepared the selected department as follows:

request.setAttribute("selectedDept", selectedDept);

then this should do:

<select name="department">
    <c:forEach var="item" items="${dept}">
        <option value="${item.key}" ${item.key == selectedDept ? 'selected="selected"' : ''}>${item.value}</option>
    </c:forEach>
</select>

回答2:

i tried the last answer from Sandeep Kumar, and i found way more simple :

<option value="1" <c:if test="${item.key == 1}"> selected </c:if>>

回答3:

If you don't mind using jQuery you can use the code bellow:

    <script>
     $(document).ready(function(){
           $("#department").val("${requestScope.selectedDepartment}").attr('selected', 'selected');
     });
     </script>


    <select id="department" name="department">
      <c:forEach var="item" items="${dept}">
        <option value="${item.key}">${item.value}</option>
      </c:forEach>
    </select>

In the your Servlet add the following:

        request.setAttribute("selectedDepartment", YOUR_SELECTED_DEPARTMENT );

回答4:

I think above examples are correct. but you dont' really need to set

request.setAttribute("selectedDept", selectedDept);

you can reuse that info from JSTL, just do something like this..

<!DOCTYPE html>
<html lang="en">
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<head>
    <script src="../js/jquery-1.8.1.min.js"></script>
</head>
<body>
    <c:set var="authors" value="aaa,bbb,ccc,ddd,eee,fff,ggg" scope="application" />
    <c:out value="Before : ${param.Author}"/>
    <form action="TestSelect.action">
        <label>Author
            <select id="Author" name="Author">
                <c:forEach items="${fn:split(authors, ',')}" var="author">
                    <option value="${author}" ${author == param.Author ? 'selected' : ''}>${author}</option>
                </c:forEach>
            </select>
        </label>
        <button type="submit" value="submit" name="Submit"></button>
        <Br>
        <c:out value="After :   ${param.Author}"/>
    </form>
</body>
</html>

回答5:

I tried the accepted answer, it did not work.

However the simple way to do it is below:-

<option value="1" <c:if test="${item.quantity == 1}"> <c:out value= "selected=selected"/</c:if>>1</option>
<option value="2" <c:if test="${item.quantity == 2}"> <c:out value= "selected=selected"/</c:if>>2</option>
<option value="3" <c:if test="${item.quantity == 3}"> <c:out value= "selected=selected"/</c:if>>3</option>

Enjoy!!

回答6:

You can try one even more simple:

<option value="1" ${item.quantity == 1 ? "selected" : ""}>1</option>

回答7:

Maybe I don't completely understand the accepted answer so it didn't work for me.

What i did was simply to check if the variable is null, assign it to a known value from my database. Which seems to be similar to the accepted answer whereby you first declare an known value and set it to selected

<select name="department">
    <c:forEach var="item" items="${dept}">
        <option value="${item.key}">${item.value}</option>
    </c:forEach>
</select>

because none of the options are selected, thus item = null

<%
    if(item == null){
        item = "selectedDept"; //known value from your database
    }
%>

This way if the user then selects another option, my IF clause will not catch it and assign to the fixed value that was declared at the start. My concept could be wrong here but it works for me

来源：https://stackoverflow.com/questions/15657367/selected-value-for-jsp-drop-down-using-jstl

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