上个小节我们写的JS代码有很多地方等待实现，这节课咱们来实现其中的入会签到功能。只要用户连接上视频会议室，就自动发送签到请求，由后端程序做判断，如果没签到就自动签到，要是签过到了，就不必重复签到。

一、编写持久层代码

在TbMeetingDao.xml文件中，定义SQL语句。

<select id="searchCanCheckinMeeting" parameterType="HashMap" resultType="long">
    SELECT COUNT( * )
    FROM tb_meeting
    WHERE id = #{meetingId}
    AND status IN( 3,4 )
    AND NOW() BETWEEN DATE_SUB(CONCAT(date," ",`start`),INTERVAL 15 MINUTE) AND DATE_ADD(CONCAT(date," ",`start`),INTERVAL 5 MINUTE)
    AND JSON_CONTAINS ( IFNULL(members,JSON_ARRAY()), CAST( #{userId} AS CHAR ) )
    AND NOT JSON_CONTAINS ( IFNULL(present,JSON_ARRAY()), CAST( #{userId} AS CHAR ) )
</select>

<update id="updateMeetingPresent" parameterType="HashMap">
    UPDATE tb_meeting
    SET present = JSON_ARRAY_APPEND ( IFNULL( present, JSON_ARRAY ( ) ), '$', #{userId} )
    WHERE id = #{meetingId}
    AND NOW() >= DATE_SUB(CONCAT(date," ",`start`), INTERVAL 15 MINUTE)
    AND NOW() &lt; DATE_SUB(CONCAT(date," ",`end`),INTERVAL 15 MINUTE)
    AND JSON_CONTAINS ( IFNULL( members, JSON_ARRAY ( ) ), CAST( #{userId} AS CHAR ) )
    AND NOT JSON_CONTAINS ( IFNULL( present, JSON_ARRAY ( ) ), CAST( #{userId} AS CHAR ) )
</update>

在TbMeetingDao.java接口中，声明DAO方法。

public interface TbMeetingDao {
    ……
    public long searchCanCheckinMeeting(HashMap param);
    public int updateMeetingPresent(HashMap param);
}

二、编写业务层代码

在MeetingService.java接口中，定义Web方法。

public interface MeetingService {
    ……
    public boolean searchCanCheckinMeeting(HashMap param);
    public int updateMeetingPresent(HashMap param);
}

在MeetingServiceImpl.java类中，实现抽象方法。

public class MeetingServiceImpl implements MeetingService {
    ……
    
    @Override
    public boolean searchCanCheckinMeeting(HashMap param) {
        long count = meetingDao.searchCanCheckinMeeting(param);
        return count == 1 ? true : false;
    }

    @Override
    public int updateMeetingPresent(HashMap param) {
        int rows = meetingDao.updateMeetingPresent(param);
        return rows;
    }
}

三、编写Web层代码

创建UpdateMeetingPresentForm.java类，封装Ajax提交的数据。

@Data
@Schema(description = "会议签到表单")
public class UpdateMeetingPresentForm {
    @NotNull(message = "meetingId不能为空")
    @Min(value = 1, message = "meetingId不能小于1")
    private Integer meetingId;
}

在MeetingController.java类中，声明Web方法。

public class MeetingController {
    ……
    @PostMapping("/updateMeetingPresent")
    @Operation(summary = "执行会议签到")
    @SaCheckLogin
    public R updateMeetingPresent(@Valid @RequestBody UpdateMeetingPresentForm form) {
        HashMap param = new HashMap() {{
            put("meetingId", form.getMeetingId());
            put("userId", StpUtil.getLoginIdAsInt());
        }};
        boolean bool = meetingService.searchCanCheckinMeeting(param);
        if (bool) {
            int rows = meetingService.updateMeetingPresent(param);
            return R.ok().put("rows", rows);
        }
        return R.ok().put("rows", 0);
    }
}

四、前端页面发起签到请求

在meeting_video.vue页面中编写JS代码，发起签到请求。

//执行签到
that.$http('meeting/updateMeetingPresent','POST', { meetingId: that.meetingId }, true,function(resp) {
    let rows = resp.rows;
    if (rows == 1) {
        that.$message({
            message: '签到成功',
            type: 'success',
            duration: 1200
        });
    }
});