前端htmlページからpdfファイルをエクスポートし、サーバにアップロードして保存します.

function loadPdf() {
        html2canvas(document.body, {
            onrendered:function(canvas) {

                var contentWidth = canvas.width;
                var contentHeight = canvas.height;

                //  pdf  html     canvas  ;
                var pageHeight = contentWidth / 595.28 * 841.89;
                //   pdf html    
                var leftHeight = contentHeight;
                //pdf    
                var position = 0;
                //a4    [595.28,841.89]，html     canvas pdf      
                var imgWidth = 555.28;
                var imgHeight = 555.28/contentWidth * contentHeight;

                var pageData = canvas.toDataURL('image/jpeg', 1.0);

                var pdf = new jsPDF('', 'pt', 'a4');
                //         ，   html       ，   pdf     (841.89)
                //      pdf       ，    
                if (leftHeight < pageHeight) {
                    pdf.addImage(pageData, 'JPEG', 20, 0, imgWidth, imgHeight );
                } else {
                    while(leftHeight > 0) {
                        pdf.addImage(pageData, 'JPEG', 20, position, imgWidth, imgHeight)
                        leftHeight -= pageHeight;
                        position -= 841.89;
                        //       
                        if(leftHeight > 0) {
                            pdf.addPage();
                        }
                    }
                }
                
                //  pdf   base      
                var buffer = pdf.output("datauristring")
                //  base64         file  
                var myfile = dataURLtoFile(buffer, pdfName)
                var formdata = new FormData()
                formdata.append(name, myfile)
                //   ajax    
            }
        })
}

// base64       
function dataURLtoFile(dataurl, filename) {
    var arr = dataurl.split(',');
    var mime = arr[0].match(/:(.*?);/)[1];
    var bstr = atob(arr[1]);
    var n = bstr.length; 
    var u8arr = new Uint8Array(n);
    while(n--){
        u8arr[n] = bstr.charCodeAt(n);
    }
    //   file  
    return new File([u8arr], filename, {type:mime});
    //    blob  
    //return new Blob([u8arr],{type:mime});
}