Exception in thread "main" java.lang.NullPointerException

at com.jfinal.plugin.activerecord.Model.find(Model.java:583)

at cn.disicn.service.BizJobsAttachmentService.getBizJobsAttachmentByJobsId(BizJobsAttachmentService.java:16)

at cn.disicn.service.BizJobsAttachmentService.main(BizJobsAttachmentService.java:24)

今天遇到好几次，求帮忙！