My model as below and add use the spring mvc.

```
@Entity
@Table(name="audit_report")
public class AuditReport implements Serializable{

/**
 * 
 */
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "audit_report_id")
private int auditReportId;
@ManyToOne(fetch=FetchType.LAZY,optional = false,cascade=CascadeType.ALL)
@JoinColumn(name="audit_factory_id")
private AuditFactory auditFactory;
@Column(name = "report_id")
private String  reportId;
@Column(name = "editor")
private String editor;
@Column(name = "engineer_name")
@NotNull
private String engineerName;
@Column(name="service_date")
@DateTimeFormat(pattern="MM/dd/yyyy")
private Date serviceDate;
@Column(name="audit_date")
@DateTimeFormat(pattern="MM/dd/yyyy")
private Date auditDate;
@OneToMany(cascade = CascadeType.ALL ,fetch = FetchType.LAZY, mappedBy = "auditReport")
@Fetch(FetchMode.SUBSELECT)
private List<Printer> printers;

```

controller as below,it will get the model and save it.

```
@ResponseBody
@RequestMapping(value = "/saveAuditReport",method = RequestMethod.POST)
public Map<String,String> newAuditReport(HttpServletRequest         request,@RequestBody AuditReport report){

```

ajax, it get the 400 error if add the serviceDate and it will ok after remove the serviceDate

```
$.ajax({
    type:"post",
    url:"<%=path%>/audit/saveAuditReport.do",
    contentType : 'application/json; charset=utf-8',
    data:JSON.stringify({'serviceDate':pnDate,'engineerName':engineer,'reportId':reportId,"auditReportId":auditReportId,"printers":array,"auditFactory":{"auditFactoryId":factoryId}}),
    dataType:'json',
    success:function(data, textStatus){
        if(data!=null){
            if(data.error==null){
                layer.msg(data.ok,1,9);
                layer.close(pageii);
                searchReportById(factoryId,obj);
            }else{
                layer.msg(data.error);
            }
        }

    },
    error : function(XMLHttpRequest, textStatus, errorThrown) {

    }
});

```

ajax, it get the 400 error if add the serviceDate and it will ok after remove the serviceDate