How to receive binary file stream in Vue to realize PDF preview

@RequestMapping("/getPDFStream")
@ResponseBody
public void getPDFStream(HttpServletRequest request,HttpServletResponse response) {
 try {
  request.setCharacterEncoding("utf-8");
 } catch (UnsupportedEncodingException e) {
  logger.error("Set character set UnsupportedEncodingException");
 }
 String fileName = request.getParameter("fileName");
 //File pathString filePathname = Const.UPLOAD_HBFILE_PATH + "/" + fileName
   + ".pdf";
 File file = new File(filePathname);
 byte[] data = null;
 if (!file.exists()) {
  logger.error("Sorry File does not Exists!");
 } else {
  try {
   FileInputStream input = new FileInputStream(file);
   data = new byte[input.available()];
   input.read(data);
   response.getOutputStream().write(data);
   input.close();
  } catch (Exception e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
   logger.error("pdf file processing exception");
  }
 }
}

import axios from 'axios'
/**
 * Method of encapsulating axios asynchronous request==================
 */
//Create an axios object-----------
const request = axios.create({
    //baseURL:'/dev-api', //Base path baseURL:process.env.VUE_APP_BASE_API, //Load different constant values ​​according to different environments // baseURL: '/',
    timeout: 50000, //Request timeout, 50000 milliseconds})
//Set up request interceptor=====================================
//Request interception--------------------
request.interceptors.request.use(config => {
    //Request interception config.data = {
        ...config.data,
        userId: sessionStorage.getItem('userId')
    }
    return config;
}, error => {
    //Exception return Promise.reject(error); //es6 writing });
//Set up response interceptor===================================
//Respond to interception--------------------
request.interceptors.response.use(response => {
    if(!response.data||response.data==""){
        return '{"flag":"failure","msg":"Unknown error"}';
    }
    return response.data;
},error =>{
    return Promise.reject(error);
})
export default request //Export custom created axios object for use by other components

import request from '@/utils/request' //Import the encapsulated axios request method export function getPDFStream(param) {
   return request({
        url: 'xxxxxx/getPDFStream',
        method: 'post',
        // Pass parameter data: param,
        headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
        responseType: 'blob',
        transformRequest: function(obj) {
            var str = [];
            for (var p in obj)
                str.push(encodeURIComponent(p) + "=" + encodeURIComponent(obj[p]));
            return str.join("&");
        },
 })
}

 <a-modal
  width="900px"
  title="File View"
  v-model="lookPdfFile"
  :footer="null"
  :forceRender="true"
  @ok="lookPdfFile"
>
  <div :style="{ height: '600px', minHeight: '500px', margin: '8px 0px' }">
     <iframe :src="pdfUrl" id="previewPdf" frameborder="0" style="width: 100%; height: 100%"></iframe>
  </div>
</a-modal>

//Import methodimport {getPDFStream} from "@/api/common";
//Define data
lookPdfFile:false, //Preview pdf
pdfUrl:'', // pdf path

 let _this = this;
 if(suffix == 'pdf'){
   getPDFStream({
     fileName: filename,
   }).then(res => {
     let reader = new window.FileReader();
     // Use readAsArrayBuffer to read the file. The result property will contain an ArrayBuffer object to represent the data of the read file. reader.readAsArrayBuffer(res);
     reader.onload = function(e) {
       const result = e.target.result
       const contentType = res.type
       // Generate blob image, requires parameters (byte array, file type)
       const blob = new Blob([result], { type: 'application/pdf' })
       // Use Blob to create a URL pointing to a typed array. URL.createObjectURL is a method of new Blob file, which can generate a normal URL and can be used directly, such as on img.src if (window.createObjectURL != undefined) { // basic
         _this.pdfUrl = window.createObjectURL(blob)+'#toolbar=0'
       } else if (window.webkitURL != undefined) { // webkit or chrome
         try {
           _this.pdfUrl = window.webkitURL.createObjectURL(blob)+'#toolbar=0'
         } catch (error) {

         }
       } else if (window.URL != undefined) { // mozilla(firefox)
         try {
           _this.pdfUrl = window.URL.createObjectURL(blob)+'#toolbar=0'
         } catch (error) {

         }
       }
     }
     this.$nextTick(() => {
       this.lookPdfFile = true;
     })
   })
   return;
 }