after the foreground clicks the file name, the background converts the doc file into a pdf file through openoffice, and then stores it in the server tomcat". After pdf.js loads the transformed pdf file in tomcat in the server for the first time, it will show that the pdf file does not exist, and the pdf file can be displayed successfully after the second refresh. How to make a preview of the pdf file appear the first time it is loaded.

<iframe id="product-doc" style="display: none;" src=""></iframe>

function fileView(fileId) {
    $.ajax({
        url: MMBS_IP + "/resources/rest/climate/alarm/showDocOnlineView",
        data: {
            fileId: fileId
        },
        type: "get",
        async: true,
        beforeSend: ajaxLoading,
        success: function(data) {
            console.log(data);
            var name = data.name.split(".",1)
            if(data.type == "img"){
                var strHtml = "";
                var imgUrl = MMBS_IP + "/resources/rest/getImageStream?imgPath=" + data.name;
                var downLoadPath = """+ data.name +"""
                strHtml += "<button id="img-download" onclick="imgDownload(";
                strHtml += downLoadPath
                strHtml += ")"></button>"
                strHtml += "<img id="product-img" style="width: 100%;height: 100%;" src=""+ imgUrl +""/>";
                var imgName = data.name.split("/")
                $("-sharpproduct-win-img").show();
                $("-sharpproduct-win-img").html(strHtml);
                $("-sharpproduct-win-img").window({
                    title: imgName[imgName.length-1].split(".",1),
                    width: 1400,
                    height: 800
                });
            }else {
                var path = MMBS_IP + "/resource/generic/web/viewer.html?file=" + data.name
                console.log(path);
                $("-sharpproduct-doc").attr("src", path);
                $("-sharpproduct-doc").show();
                $("-sharpproduct-doc").window({
                    title: name,
                    width: 1400,
                    height: 800
                });
            }
        },
        error: function(xhr, textStatus) {
            $.messager.alert("", "!", "info");
        },
        complete: ajaxLoadEnd
    });
};

@RequestMapping(value = "showDocOnlineView", method = RequestMethod.GET)
    public @ResponseBody Map<String, Object> showDocOnlineView(HttpServletRequest request, HttpServletResponse response) 
    {
        Map<String,Object> file = FileMgrService.findFileById(Integer.parseInt(request.getParameter("fileId")));
        Map<String, Object> resultMap = new HashMap<String, Object>();
        String path = request.getServletContext().getRealPath("/resource/generic/web/" + file.get("display_name").toString() +".pdf");
        String name = "";
        if (file.get("file_type").toString().equals("img")) {
            name = file.get("file_path").toString();
        }else {
            try {
                name = file.get("display_name").toString() +".pdf";
                File inputFile = new File(file.get("file_path").toString());  
                File outputFile = new File(path);  
                DOC2PDFUtil dp = new DOC2PDFUtil(inputFile,outputFile);
                dp.start();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        resultMap.put("type", (file.get("file_type")));
        resultMap.put("name", name);
        return resultMap;
    }

screenshot of failed loading for the first time

iframe