Spring #ModelAttributes auto binding - spring

Question

Hi i am tring to use #ModelAttributes for auto binding from view to controller.
this jsp page should send all elements which is Personal Schedule VO.
<form name="insertFrm" action="myScheduleInsert" method="POST">
<ul>
<input type="hidden" class="form-control" name="perschd_num" >
<li>
<label class='control-label'>title</label>
<input type="text" class="form-control" name="perschd_title" >
</li>
<li>
<input type="hidden" class="form-control" name="perschd_writer" >
<li>
<label class='control-label'>start date</label>
<input type="date" id="fullYear" class="form-control" name="perschd_start_date" value="">
</li>
<li>
<label class='control-label'>end date</label>
<input type="date" class="form-control" name="perschd_end_date" >
</li>
<li>
<label class='control-label'>content</label>
<input type="text" class="form-control" name="perschd_cont" >
</li>
</ul>
</div>
<!-- button-->
<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
<input type="submit" class="btn btn-primary">
</form>
and this is my controller for insert feature by using #ModelAttributes PerschdVO perschd and when i try print all out, all is null.
//insertSchedule
#RequestMapping("/myScheduleInsert")
public String myScheduleInsert(#ModelAttribute PerschdVO perschdVO ){
String view="redirect:/professor/mypage/mySchedule";
*System.out.println(perschdVO);*
try {
proService.insertPerschd(perschdVO);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return view;
}
and this is PerschdVO
public class PerschdVO {
private int perschd_num;
private String perschd_title;
private String perschd_cont;
private Date perschd_date;
private String perschd_start_date;
private String perschd_end_date;
private String perschd_writer; //id
public String getPerschd_writer() {
return perschd_writer;
}
public void setPerschd_writer(String perschd_writer) {
this.perschd_writer = perschd_writer;
}
public int getPerschd_num() {
return perschd_num;
}
public void setPerschd_num(int perschd_num) {
this.perschd_num = perschd_num;
}
public String getPerschd_title() {
return perschd_title;
}
public void setPerschd_title(String perschd_title) {
this.perschd_title = perschd_title;
}
public String getPerschd_cont() {
return perschd_cont;
}
public void setPerschd_cont(String perschd_cont) {
this.perschd_cont = perschd_cont;
}
public Date getPerschd_date() {
return perschd_date;
}
public void setPerschd_date(Date perschd_date) {
this.perschd_date = perschd_date;
}
public String getPerschd_start_date() {
return perschd_start_date;
}
public void setPerschd_start_date(String perschd_start_date) {
this.perschd_start_date = perschd_start_date;
}
public String getPerschd_end_date() {
return perschd_end_date;
}
public void setPerschd_end_date(String perschd_end_date) {
this.perschd_end_date = perschd_end_date;
}
why this elements from jsp does not match with this? Eventhough i matched all name in jsp file to PerschdVO's get() names.
and if i fix like this
public String myScheduleInsert(
Principal who,
#RequestParam("perschd_start_date")String perschd_start_date,
#RequestParam("perschd_end_date")String perschd_end_date,
#RequestParam("perschd_title")String perschd_title,
#RequestParam("perschd_cont")String perschd_cont
){
PerschdVO perschdVO = new PerschdVO();
...}
than the data from jsp could be sent to #Controller, but still can't get informations about using #ModelAttributes. cos if i use that always 400 bad request happened.