修改

src/main/java/com/ycwl/basic/model/pc/device/resp/DeviceRespVO.java

@@ -37,4 +37,6 @@ public class DeviceRespVO {
     private Date updateAt;
     @ApiModelProperty("景区名称")
     private String scenicName;
+    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
+    private Date keepaliveAt;
 }

src/main/resources/mapper/DeviceMapper.xml

@@ -52,7 +52,7 @@
         delete from device where id = #{id}
     </delete>
     <select id="list" resultType="com.ycwl.basic.model.pc.device.resp.DeviceRespVO">
-        select d.id, scenic_id, d.name, no, d.longitude, d.latitude, d.status, create_at, d.update_at, s.name scenic_name
+        select d.id, scenic_id, d.name, no, d.longitude, d.latitude, d.status, create_at, d.update_at, s.name scenic_name, d.keepalive_at
         from device d
         left join scenic s on d.scenic_id = s.id
         <where>