onInterceptRequest拦截本地pdf文件，前端不显示

Web({ src: 'www.example.com', controller: this.controller }) 
  .onInterceptRequest((event) => { 
    console.log('url:' + event.request.getRequestUrl()) 
    this.responseweb = new WebResourceResponse(); 
    var head1:Header = { 
      headerKey:"Connection", 
      headerValue:"keep-alive" 
    } 
    var length = this.heads.push(head1) 
    this.responseweb.setResponseHeader(this.heads) 
    this.responseweb.setResponseData(this.webdata) 
    this.responseweb.setResponseEncoding('utf-8') 
    this.responseweb.setResponseMimeType('text/html') 
    this.responseweb.setResponseCode(200) 
    this.responseweb.setReasonMessage('OK') 
    return this.responseweb 
  })