接口调用拿到pdf的文件流，用blob处理这个文件流拿到url，使用window.open跳转新的窗口进行预览

api({
	dataType: 'blob',
}).then(res =>{
	if(res.code === 0){
	   this.previewPDF(
	     res,
	     'application/pdf;charset=utf-8',
	     'pdf文件名'
	   )
	 }
})

previewPDF (res, type, fname) {
    try {
      if(!res|| !res.data || !res.headers) {
        throw new Error("Invalid response")
      }
      const fileType = res.headers['content-type'] || type
      console.log(res.headers['content-type'])  
      const blob = new Blob([res.data], {type: fileType})
      console.log(blob)  
      const urlObject = URL.createObjectURL(blob)
      console.log(urlObject ) 
      window.open(urlObject, '_blank');
    }catch(err) {
      throw new Error("预览失败")
    }
}

接口返回的数据

打印res.headers['content-type']

响应头

请求头

打印blob

打印urlObject

文件预览