Spring MVC - Submit Form 400 Error - spring

Question

I'm just begin writing an application using Spring MVC. I have 2 entities, District & City. A City has many districts, and each district belongs to a city.
In district.jsp I declare a form, allowing user input of the district name and a selection box to choose the City it belongs to.
The District entity looks like this:
<form:form action="${aAction}" commandName="district">
<table>
<c:if test="${!empty district.districtName}">
<tr>
<td>
<form:label path="id">
<spring:message text="ID"/>
</form:label>
</td>
<td>
<form:input path="id" readonly="true" size="8" disabled="true" />
<form:hidden path="id" />
</td>
</tr>
</c:if>
<tr>
<td>
<form:label path="districtName">
<spring:message text="District Name"/>
</form:label>
</td>
<td>
<form:input path="districtName" />
</td>
</tr>
<tr>
<td>
<form:label path="belongToCity">
<spring:message text="Belong to City"/>
</form:label>
</td>
<td>
<c:if test="${!empty listCities}">
<form:select path="belongToCity" items="${listCities}" itemLabel="cityName" itemValue="id"></form:select>
</c:if>
</td>
</tr>
<tr>
<td colspan="2">
<c:if test="${!empty district.districtName}">
<input type="submit"
value="<spring:message text="Edit District"/>" />
</c:if>
<c:if test="${empty district.districtName}">
<input type="submit"
value="<spring:message text="Add District"/>" />
</c:if>
</td>
</tr>
</table>
</form:form>
In my district controller I declare add action.
#RequestMapping(value = {"/district/add"}, method = RequestMethod.POST)
public String addDistrict(#ModelAttribute("district") District p,Model model, BindingResult result) {
if(result.hasErrors()) {
return "district";
}
this.districtService.addDistrict(p);
return "district";
}
When I run my project, however, it shows a 400 error and the error message: "The request sent by the client was syntactically incorrect."
I suspect my form is wrong somewhere, maybe it is not able to post to controller processing. Could someone help me identify the issue?

Answer 1

Your BindingResult parameter should be adjacent to modelAttribute. Below should be method signature.
#RequestMapping(value = {"/district/add"}, method = RequestMethod.POST)
public String addDistrict(#ModelAttribute("district") District p, BindingResult result, Model model) {
if(result.hasErrors()) {
return "district";
}
this.districtService.addDistrict(p);
return "district";
}