参考了别人的文章，整合一下，写了这篇笔记
安装两个依赖
将页面html转换成图片

cnpm install --save html2canvas 

将图片生成pdf

cnpm install jspdf --save

把htmlToPdf.js(在上传中心可以找到我上传的这个js)放到文件夹中，这里放到的是“src\components\base”
在main.js里引用

import htmlToPdf from './components/base/htmlToPdf.js'
Vue.use(htmlToPdf)

页面代码

<template>
	<div class="a4Page">
		<button class="btn btn-primary" @click="getPdf()">生成PDF</button>
	</div>
	<div id="printPage"> 
   	 <br>内容
    </div>
</template>
<script>
  import restHelper from '../service/RestApiHelper.js'
  import html2Canvas from 'html2canvas'
  import JsPDF from 'jspdf'
	export default {
		methods:{
			getPdf:function(){
		        var title = “导出名称”;
		        html2Canvas(document.querySelector('#printPage'), {
		        // allowTaint: true
		        useCORS:true//看情况选用上面还是下面的，
		       }).then(function (canvas) {
		        let contentWidth = canvas.width
		        let contentHeight = canvas.height
		        let pageHeight = contentWidth / 592.28 * 841.89
		        let leftHeight = contentHeight
		        let position = 0
		        let imgWidth = 575.28
		        let imgHeight = 592.28 / contentWidth * contentHeight
		        let pageData = canvas.toDataURL('image/jpeg', 1.0)
		        let PDF = new JsPDF('', 'pt', 'a4')
		        if (leftHeight < pageHeight) {
		          PDF.addImage(pageData, 'JPEG', 10, 10, imgWidth, imgHeight)
		        } else {
		          while (leftHeight > 0) {
		            PDF.addImage(pageData, 'JPEG', 10, position, imgWidth, imgHeight)//这里的10是左右边距
		            leftHeight -= pageHeight
		            position -= 841.89
		            if (leftHeight > 0) {
		              PDF.addPage()
		            }
		          }
		        }
		        PDF.save(title + '.pdf')
	      })
	    },
   	 }
   }

如果生成的pdf较模糊，可以将canvas的属性width和height属性放大为2倍，再将canvas的css样式width和height设置为原来1倍的大小即可，也就是，先将canvas高分辨率输出，再来压缩导出打印，修改getPdf的方法为如下，

getPdf:function(){
        var title = this.htmlTitle+this.contract.contractNO;
        var dom=document.getElementById('#printPage')
        var c = document.createElement("canvas")
        var opts = {
          scale: 2, 
          canvas: c, 
          logging: true, 
          width: document.querySelector('#printPage').width, 
          height: document.querySelector('#printPage').height 
        };
        c.width = document.querySelector('#printPage').width * 2
        c.height = document.querySelector('#printPage').height * 2
        c.getContext("2d").scale(2, 2);
        html2Canvas(document.querySelector('#printPage'), opts).then(function (canvas) {
          let contentWidth = canvas.width
          let contentHeight = canvas.height
          let pageHeight = contentWidth / 592.28 * 841.89
          let leftHeight = contentHeight
          let position = 0
          let imgWidth = 575.28
          let imgHeight = 592.28 / contentWidth * contentHeight
          let pageData = canvas.toDataURL('image/jpeg', 1.0)
          let PDF = new JsPDF('', 'pt', 'a4')
          if (leftHeight < pageHeight) {
            PDF.addImage(pageData, 'JPEG', 10, 10, imgWidth, imgHeight)
          } else {
            while (leftHeight > 0) {
              PDF.addImage(pageData, 'JPEG', 10, position, imgWidth, imgHeight)
              leftHeight -= pageHeight
              position -= 841.89
              if (leftHeight > 0) {
                PDF.addPage()
              }
            }
          }
          PDF.save(title + '.pdf')
        })
      }
    },