Spring 3.0 formatters not being applied on JSP

[davoz]

Hi Spring experts,

I have a problem trying to get formatters to be applied when I return a list of my model object. It works when saving/binding the object but not when displaying the objects in a list.

Here's the scenario.

public class Customer {
    @Numberformat(pattern="#,###.00")
    BigDecimal salary;
}

The format is applied when saving. eg

<form:form commandName="customer">
    ...
    <spring:bind path="salary">
        <input type="text" ... value="${status.value}"/>
    </spring:bind>
</form:form>

However, when I have List<Customer> and am iterating through each and displaying on a table, I can't get the formatter to apply. eg

<table>
    <c:forEach items="${customers}" var="customer">
        <c:set var="customer" value="${customer}" scope="request"/>
        <tr>
            <td><spring:bind path="customer.salary">${status.value}</spring:bind></td>
        </tr>
    </c:forEach>
</table>

I've also tried to wrap the bind in a <form:form> but it also doesn't work. eg

<td>
    <form:form commandName="customer">
        <spring:bind path="salary">${status.value}</spring:bind>
    </form:form>
</td>

I'm guessing that's because there isn't a request model object bound to BindingResult.MODEL_KEY_PREFIX + "customer" ... but how do I get one in there when iterating through my List<Customer>?

Can someone show me where I went wrong here and how I can activate the formatters?

thanks,
dave

[davoz]

I found the problem. It is located in HandlerMethodInvoker.updateModelAttributes() which exposes a BindingResult only if the entry in the model satisfies isBindingCandidate(). Collections (and Lists) are excluded so no custom editors/formatters are exposed.

I have created a simple tag which I wrap my jsp code to create a binder, invoke doBody and then via reflections clear the RequestContext.errorsMaps. I could then use it like so:

<c:forEach items="${customers}" var="customer" varStatus="status">
    <ui:bind var="customer" value="${customer}" pageContext="<%=pageContext%>">
        ....
        <td><spring:bind path="salary">${status.value}</spring:bind></td>
        ....
    </ui:bind>
</c:forEach>

My <ui:bind> tag looks something like so:

<%@ attribute name="var" required="true" rtexprvalue="true" %>
<%@ attribute name="value" required="true" rtexprvalue="true" type="java.lang.Object" %>
<%@ attribute name="pageContext" required="true" rtexprvalue="true" type="javax.servlet.jsp.PageContext" %>

<spring:nestedPath path="${var}">
    <%
        // create WebDataBinder, do bind and export BindingResult using var as the objectName and value as the target
        // ...
    %>
    <jsp:doBody/>
    <%
        RequestContext requestContext = (RequestContext) pageContext.getAttribute(RequestContextAwareTag.REQUEST_CONTEXT_PAGE_ATTRIBUTE);
        if (requestContext != null) {
            // use reflections to get to errorsMap, making it accessible before setting it's value (it is declared private)
            // errors map has to be updated because it caches entries
            Map errorsMap = (Map) ReflectionUtils.getFieldValue(requestContext, "errorsMap");
            if (errorsMap != null) {
                errorsMap.remove(var);
            }
        }
    %>
</spring:nestedPath>

Not sure how many rules of design this violates, but it works. Now I can leverage my custom editors for lists that are returned from the Controller.

[nestoru]

This is old now but still shows up in Google first search page. Using <spring:eval/> tag in 3.1 looks like the way to go. I have documented how to use the Formatters and how to enhance the current @NumberFormat in http://thinkinginsoftware.blogspot.c...on-driven.html

Hopefully the Spring team will make some enhancements like the ones I am proposing for example for Rounding.