由于项目自定义比较高，所以按照下面方式实现了，附件下载。
apex :传入关联记录id
@AuraEnabled(cacheable=true) public static Map<String, Object> getAttachmentInfo(String partnerOrderId){ Map<String, Object> resMap = new Map<String, Object>(); try { resMap.put('status', 'success'); List<ContentDocumentLink> contentDL = [select ContentDocumentId from ContentDocumentLink where LinkedEntityId =:partnerOrderId]; List<String> contentDocumentIdList = new List<String>(); for (ContentDocumentLink contentRec : contentDL) { contentDocumentIdList.add(contentRec.ContentDocumentId); } List<ContentVersion> datas = [select ContentDocumentId, VersionDataUrl,Title from ContentVersion where ContentDocumentId in:contentDocumentIdList AND IsLatest = true]; resMap.put('datas', datas); } catch (Exception e) { resMap.put('status', 'fail'); resMap.put('error', e.getMessage()+'\n'+e.getStackTraceString()); } return resMap; } html: <div for:each={attachmentList} for:item="attachment" for:index="index" class="attachment-row" key={attachment.ContentDocumentId}> <div class="attachment-row-item"> <img src={attachmentGreyIcon} style="margin-right: 8px;"/> {attachment.Title} </div> <div class="attachment-row-item attchment-action"> <img src={viewIcon} alt="" style="margin-right: 12px;"> <a class="download-herf"> <img src={downloadIcon} alt="" onclick={downloadAttachmentMethod} data-recid={attachment.ContentDocumentId}> </a> </div> </div> javascript: @wire(getAttachmentInfo,{partnerOrderId:'$partnerOrderId'}) getAttachmentInfo(value){ const { data, error } = value; // destructure the provisioned value if (data) { if (data.status === "success") { console.log("data.datas.length:"+data.datas.length); this.attachmentList = data.datas; } else { this.showToast("error","",data.error); } } else if (error) { console.log('(error---> ' + JSON.stringify(error)); } } downloadAttachmentMethod(event){ var idexGet = event.target.getAttribute('data-recid'); getAttachmentSalesBussinessData({contentDocId:idexGet}).then(value => { const data = value; // destructure the provisioned value if (data.status === "success") { var contentRec = data.datas; var bstr = atob(contentRec.VersionData); var n = bstr.length; var u8arr = new Uint8Array(n);while (n--) { u8arr[n] = bstr.charCodeAt(n); } var blobRec = new Blob([u8arr], { type: contentRec.FileType }); var aherf = this.template.querySelector('.download-herf'); aherf.setAttribute("href",blobRec); aherf.setAttribute("download",contentRec.Title); aherf.setAttribute("target","_blank"); aherf.click(); } else { } }) } 标签：value,ContentDocumentLink,var,ContentVersion,resMap,error,salesfoce,data,datas From： https://www.cnblogs.com/salesforcelizhi/p/17588761.html