{                            xtype: 'datetimefield',
                            fieldLabel: '贴单日期',
                            id :'sticker_date',
                            name :'stickerDate' ,
                            format: 'Y-m-d H:i:s',
                            allowBlank : false,
                            style : 'ime-mode:disabled',
                            maxLength : 40,
                            enableKeyEvents : true,
                            width : 220
                        },
怎样设置时间默认值