LayUi集成下载Excel、word、PDF、CSV扩展

Excel、CSV
Word
PDF

根据项目需求，主要用的layui这个前段框架，现在需要支持将页面下载为四种格式的文件。

Excel、CSV

第一步：去layUi官网中找到对应的扩展文档；
下载对应的扩展文件，导入项目中。
根据文档的写法。初始化Excel控件

layui.config({base: 'layui_exts/', // 配置一个可访问地址
}).extend({excel: 'excel',
});
layui.use(['excel'], function (){//导出格式在这里改变类型就行了//layui.excel.exportExcel([[1, 2, 3]], '表格导出.xlsx', 'xlsx')layui.excel.exportExcel([[1, 2, 3]], '表格导出.csv', 'csv')
})

文档官方地址：
http://excel.wj2015.com/_book/
页面：

下载的Excel效果：

下载的CSV效果：

Word

第一步：导入js文件

    <script type="text/javascript" src="../layui/layui.js"></script><script type="text/javascript" src="../extend/FileSaver.js"></script><script type="text/javascript" src="../extend/wordexport.js"></script>

FileSaver.js代码：

/*
* FileSaver.js
* A saveAs() FileSaver implementation.
*
* By Eli Grey, http://eligrey.com
*
* License : https://github.com/eligrey/FileSaver.js/blob/master/LICENSE.md (MIT)
* source  : http://purl.eligrey.com/github/FileSaver.js
*/// The one and only way of getting global scope in all environments
// https://stackoverflow.com/q/3277182/1008999
layui.define(["jquery"], function (exports) {
var jQuery = layui.jquery;var obj = (function($) {var _global = typeof window === 'object' && window.window === window? window : typeof self === 'object' && self.self === self? self : typeof global === 'object' && global.global === global? global: thisfunction bom (blob, opts) {if (typeof opts === 'undefined') opts = { autoBom: false }else if (typeof opts !== 'object') {console.warn('Deprecated: Expected third argument to be a object')opts = { autoBom: !opts }}// prepend BOM for UTF-8 XML and text/* types (including HTML)// note: your browser will automatically convert UTF-16 U+FEFF to EF BB BFif (opts.autoBom && /^\s*(?:text\/\S*|application\/xml|\S*\/\S*\+xml)\s*;.*charset\s*=\s*utf-8/i.test(blob.type)) {return new Blob([String.fromCharCode(0xFEFF), blob], { type: blob.type })}return blob}function download (url, name, opts) {var xhr = new XMLHttpRequest()xhr.open('GET', url)xhr.responseType = 'blob'xhr.onload = function () {saveAs(xhr.response, name, opts)}xhr.onerror = function () {console.error('could not download file')}xhr.send()}function corsEnabled (url) {var xhr = new XMLHttpRequest()// use sync to avoid popup blockerxhr.open('HEAD', url, false)try {xhr.send()} catch (e) {}return xhr.status >= 200 && xhr.status <= 299}// `a.click()` doesn't work for all browsers (#465)function click (node) {try {node.dispatchEvent(new MouseEvent('click'))} catch (e) {var evt = document.createEvent('MouseEvents')evt.initMouseEvent('click', true, true, window, 0, 0, 0, 80,20, false, false, false, false, 0, null)node.dispatchEvent(evt)}}// Detect WebView inside a native macOS app by ruling out all browsers// We just need to check for 'Safari' because all other browsers (besides Firefox) include that too// https://www.whatismybrowser.com/guides/the-latest-user-agent/macosvar isMacOSWebView = /Macintosh/.test(navigator.userAgent) && /AppleWebKit/.test(navigator.userAgent) && !/Safari/.test(navigator.userAgent)var saveAs = _global.saveAs || (// probably in some web worker(typeof window !== 'object' || window !== _global)? function saveAs () { /* noop */ }// Use download attribute first if possible (#193 Lumia mobile) unless this is a macOS WebView: ('download' in HTMLAnchorElement.prototype && !isMacOSWebView)? function saveAs (blob, name, opts) {var URL = _global.URL || _global.webkitURLvar a = document.createElement('a')name = name || blob.name || 'download'a.download = namea.rel = 'noopener' // tabnabbing// TODO: detect chrome extensions & packaged apps// a.target = '_blank'if (typeof blob === 'string') {// Support regular linksa.href = blobif (a.origin !== location.origin) {corsEnabled(a.href)? download(blob, name, opts): click(a, a.target = '_blank')} else {click(a)}} else {// Support blobsa.href = URL.createObjectURL(blob)setTimeout(function () { URL.revokeObjectURL(a.href) }, 4E4) // 40ssetTimeout(function () { click(a) }, 0)}}// Use msSaveOrOpenBlob as a second approach: 'msSaveOrOpenBlob' in navigator? function saveAs (blob, name, opts) {name = name || blob.name || 'download'if (typeof blob === 'string') {if (corsEnabled(blob)) {download(blob, name, opts)} else {var a = document.createElement('a')a.href = bloba.target = '_blank'setTimeout(function () { click(a) })}} else {navigator.msSaveOrOpenBlob(bom(blob, opts), name)}}// Fallback to using FileReader and a popup: function saveAs (blob, name, opts, popup) {// Open a popup immediately do go around popup blocker// Mostly only available on user interaction and the fileReader is async so...popup = popup || open('', '_blank')if (popup) {popup.document.title =popup.document.body.innerText = 'downloading...'}if (typeof blob === 'string') return download(blob, name, opts)var force = blob.type === 'application/octet-stream'var isSafari = /constructor/i.test(_global.HTMLElement) || _global.safarivar isChromeIOS = /CriOS\/[\d]+/.test(navigator.userAgent)if ((isChromeIOS || (force && isSafari) || isMacOSWebView) && typeof FileReader !== 'undefined') {// Safari doesn't allow downloading of blob URLsvar reader = new FileReader()reader.onloadend = function () {var url = reader.resulturl = isChromeIOS ? url : url.replace(/^data:[^;]*;/, 'data:attachment/file;')if (popup) popup.location.href = urlelse location = urlpopup = null // reverse-tabnabbing #460}reader.readAsDataURL(blob)} else {var URL = _global.URL || _global.webkitURLvar url = URL.createObjectURL(blob)if (popup) popup.location = urlelse location.href = urlpopup = null // reverse-tabnabbing #460setTimeout(function () { URL.revokeObjectURL(url) }, 4E4) // 40s}})_global.saveAs = saveAs.saveAs = saveAsif (typeof module !== 'undefined') {module.exports = saveAs;}
})(jQuery);exports("FileSaver", obj);
});

wordexport.js代码：

layui.define(["jquery"], function (exports) {
var jQuery = layui.jquery;if (typeof jQuery !== "undefined" && typeof saveAs !== "undefined") {var obj = (function($) {$.fn.wordExport = function(fileName,style) {fileName = typeof fileName !== 'undefined' ? fileName : "jQuery-Word-Export";var static = {mhtml: {top: "Mime-Version: 1.0\nContent-Base: " + location.href + "\nContent-Type: Multipart/related; boundary=\"NEXT.ITEM-BOUNDARY\";type=\"text/html\"\n\n--NEXT.ITEM-BOUNDARY\nContent-Type: text/html; charset=\"utf-8\"\nContent-Location: " + location.href + "\n\n<!DOCTYPE html>\n<html>\n_html_</html>",head: "<head>\n<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">\n<style>\n_styles_\n</style>\n</head>\n",body: "<body>_body_</body>"}};var options = {maxWidth: 624};// Clone selected element before manipulating it//clone()，复制var markup = $(this).clone();// Remove hidden elements from the outputmarkup.each(function() {var self = $(this);//我这里是将HTML中的冻结窗口元素排除掉self.find("div.layui-table-fixed").remove();self.find("div.layui-table-body table div").remove();//设置内联样式self.find("th").css("width",'140px');self.find("td").css("width",'140px');if (self.is(':hidden'))self.remove();});// Embed all images using Data URLsvar images = Array();var img = markup.find('img');for (var i = 0; i < img.length; i++) {// Calculate dimensions of output imagevar w = Math.min(img[i].width, options.maxWidth);var h = img[i].height * (w / img[i].width);// Create canvas for converting image to data URLvar canvas = document.createElement("CANVAS");canvas.width = w;canvas.height = h;// Draw image to canvasvar context = canvas.getContext('2d');context.drawImage(img[i], 0, 0, w, h);// Get data URL encoding of imagevar uri = canvas.toDataURL("image/png");$(img[i]).attr("src", img[i].src);img[i].width = w;img[i].height = h;// Save encoded image to arrayimages[i] = {type: uri.substring(uri.indexOf(":") + 1, uri.indexOf(";")),encoding: uri.substring(uri.indexOf(";") + 1, uri.indexOf(",")),location: $(img[i]).attr("src"),data: uri.substring(uri.indexOf(",") + 1)};}// Prepare bottom of mhtml file with image datavar mhtmlBottom = "\n";for (var i = 0; i < images.length; i++) {mhtmlBottom += "--NEXT.ITEM-BOUNDARY\n";mhtmlBottom += "Content-Location: " + images[i].location + "\n";mhtmlBottom += "Content-Type: " + images[i].type + "\n";mhtmlBottom += "Content-Transfer-Encoding: " + images[i].encoding + "\n\n";mhtmlBottom += images[i].data + "\n\n";}mhtmlBottom += "--NEXT.ITEM-BOUNDARY--";//TODO: load css from included stylesheet// var styles = style;// var styles = '';var styles = style;// Aggregate parts of the file togethervar fileContent = static.mhtml.top.replace("_html_", static.mhtml.head.replace("_styles_", styles) + static.mhtml.body.replace("_body_", markup.html())) + mhtmlBottom;console.info("fileContent",fileContent);// Create a Blob with the file contentsvar blob = new Blob([fileContent], {type: "application/msword;charset=utf-8"});saveAs(blob, fileName + ".doc");};})(jQuery);
} else {if (typeof jQuery === "undefined") {console.error("jQuery Word Export: missing dependency (jQuery)");}if (typeof saveAs === "undefined") {console.error("jQuery Word Export: missing dependency (FileSaver.js)");}
}exports("wordexport", obj);
});

其中的FileSaver.js和wordexport.js是在layui官网的扩展中找到对应的扩展文档，下载的。

当js文件引入后，自选集需要写的代码就是下面这几句了，很简单：

let style = "";
//这里的style是自定义导出的Word文档里面的样式，我这里导出的是表格，所以在修改表格单元格宽度
style+=".layui-table-body table tr td{width:140px;}";
$("div[lay-id='myTable']").wordExport(“导出Word文档名称”,style);

这里我发现，导出的文档存在问题：

表头和数据部分单元格对不齐，这个问题正在想办法解决，后期解决了再更新吧。
经过我两天的碰壁，换了种方法解决了这个问题：
在wordexport.js文件中的下图位置，只获取页面的数据，自己重新生成一个table的html代码，情况复制的对象，重新填充HTML代码，在导出，就解决了格式对不齐的问题。这里应为无论怎么尝试调整样式都无法解决，所以退而求其次了。

重新组装个table对象：

最后效果：

PDF

需要引入的js文件：

    <script type="text/javascript" src="../html2canvas.js"></script><script type="text/javascript" src="../jspdf.debug.js"></script>

这两个文件在网上找找都能找到，下载就可以了。
引入js文件以后，当然就是自己写的js代码块了：

function exportPdf() {//获取需要转换的部分的对象//也可以直接在对象上添加id属性，$(“#id”)直接获取对象var target = $("div .layui-table-box");//注意：这两句代码是给对象添加内联样式的宽度和高度//如果存在滚动条的情况，这两句就非常关键了，添加内联样式以后，下载的PDF是全部，包括滚动条隐藏的部分，如果不添加，只能下载当前可视部门target.css('width',($("div .layui-table-body table").width()) + "px");target.css('height',($("div .layui-table-body table").height()+$("div .layui-table-header table").height()) + "px");html2canvas(target, {onrendered:function(canvas) {let contentWidth = canvas.width;let contentHeight = canvas.height;//一页pdf显示html页面生成的canvas高度;let pageHeight = contentWidth / 592.28 * 841.89;//未生成pdf的html页面高度let leftHeight = contentHeight;//页面偏移let position = 0;//a4纸的尺寸[595.28,841.89]，html页面生成的canvas在pdf中图片的宽高let imgWidth = 595.28;let imgHeight = 592.28/contentWidth * contentHeight;let pageData = canvas.toDataURL('image/jpeg', 1.0);let pdf = new jsPDF('', 'pt', 'a4');//有两个高度需要区分，一个是html页面的实际高度，和生成pdf的页面高度(841.89)//当内容未超过pdf一页显示的范围，无需分页if (leftHeight < pageHeight) {pdf.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight );} else {while(leftHeight > 0) {pdf.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight)leftHeight -= pageHeight;position -= 841.89;//避免添加空白页if(leftHeight > 0) {pdf.addPage();}}}pdf.save("下载的PDF的名称.pdf");//在下载完场后，得去掉内联样式，这样才不影响页面的滚动条效果target.removeAttr("style");}})}

之前我在解决滚动条影响的问题的时候，看见网上说的复制一个对象，添加到body中的做法，这种会影响页面布局、显示等，体验很差，可能是我未处理好的问题吧，我这种处理方法感觉也还行，就站不考虑那么多了。
下载的PDF文件，是有自动翻页功能的，当高度超过A4纸高度，会自动添加一页。

下载的效果：