vue实现pdf文档在线预览功能

<template>
 <div>
 <canvas v-for="page in pages" :id="'the-canvas'+page" :key="page"></canvas>
 </div>
</template>
 
<script>
// 方式一
import PDFJS from 'pdfjs-dist'
// 方式二
import * as PDFJS from '../../../static/pdf/build/pdf'
 
export default {
 // 返回数据
 data () {
 return {
 pdfDoc: null,
 pages: 0
 }
 },
 created () {
 },
 mounted () {
 this.showPdf()
 },
 methods: {
 showPdf: function () {
 // 请求本地文件
 let url = '/static/pdf/web/compressed.tracemonkey-pldi-09.pdf'
 // 跨域请求文件，需要走后台代理，后台需要将文件流返回前端才可在页面显示
 // let url = '/pdf/showPdf?pdfUrl=http://test.hccb.cc/corporBankWXTest/static/123.pdf'
 this.loadFile(url)
 },
 renderPage: function (num) {
 let _this = this
 this.pdfDoc.getPage(num).then(function (page) {
 let canvas = document.getElementById('the-canvas' + num)
 let ctx = canvas.getContext('2d')
 let dpr = window.devicePixelRatio || 1.0
 let bsr = ctx.webkitBackingStorePixelRatio ||
  ctx.mozBackingStorePixelRatio ||
  ctx.msBackingStorePixelRatio ||
  ctx.oBackingStorePixelRatio ||
  ctx.backingStorePixelRatio || 1.0
 let ratio = dpr / bsr
 let viewport = page.getViewport(window.screen.availWidth / page.getViewport(1).width)
 canvas.width = viewport.width * ratio
 canvas.height = viewport.height * ratio
 canvas.style.width = viewport.width + 'px'
 canvas.style.height = viewport.height + 'px'
 ctx.setTransform(ratio, 0, 0, ratio, 0, 0)
 var renderContext = {
  canvasContext: ctx,
  viewport: viewport
 }
 page.render(renderContext)
 if (_this.pages > num) {
  _this.renderPage(num + 1)
 }
 })
 },
 loadFile: function (url) {
 let _this = this
 PDFJS.getDocument(url).then(function (pdf) {
 _this.pdfDoc = pdf
 _this.pages = _this.pdfDoc.numPages
 _this.$nextTick(() => {
  _this.renderPage(1)
 })
 })
 }
 }
}
</script>
 
<style scoped>
canvas {
 display: block;
 border-bottom: 1px solid black;
}
</style>

<template>
 <div >
 <iframe :src="url" id="iframe" style="width: 100%;" @load="sureHeight"></iframe>
 </div>
</template>
 
<script>
export default {
 // 返回数据
 data () {
 return {
 url: ''
 }
 },
 // 模块创建时执行
 created () {
 },
 // 模块渲染时执行
 mounted () {
 // 本地请求文件
 let filePath = encodeURIComponent('/static/pdf/web/compressed.tracemonkey-pldi-09.pdf')
 // 跨域请求文件，需走后台代理
 // let filePath2 = encodeURIComponent('/pdf/showPdf?pdfUrl=http://test.hccb.cc/corporBankWXTest/static/123.pdf')
 // pdf文档展示的页面
 this.url = '/static/pdf/web/viewer.html?file=' + filePath
 },
 // 定义模块测试方法
 methods: {
 // 此方法用于动态确定元素iframe的高度，使展示的pdf文档占满整个屏幕
 sureHeight: function () {
 let element = document.getElementById('iframe')
 element.style.height = window.screen.height + 'px'
 }
 }
}
</script>
 
<style scoped>
 
</style>

@Controller
public class ShowPdfController {
 @RequestMapping(name = "/showPdf")
 public String showPdf(HttpServletRequest request, HttpServletResponse response, String pdfUrl) {
 try {
  pdfUrl = pdfUrl.trim();
  URL url = new URL(pdfUrl);
  HttpURLConnection conn = (HttpURLConnection) url.openConnection();
  conn.setConnectTimeout(5*1000);
  InputStream inputStream = conn.getInputStream();
  response.setHeader("Content-Disposition", "attachment;fileName=show.pdf");
  response.setContentType("multipart/form-data");
  OutputStream outputStream = response.getOutputStream();
  IOUtils.write(IOUtils.toByteArray(inputStream), outputStream);
 } catch (Exception e) {
  e.printStackTrace();
 }
 return null;
 }
}