vue接收springboot后端返回的文件流，大小没有错，为啥excel与word打不开，打开是乱码，txt可以正常打开？

Question

    public String downloadFile (HttpServletRequest request,HttpServletResponse response,com.sunyard.cusprotect.entities.File downfile)  {

        try {
            // 不使用客户端传来的文件名，使用数据库查出来的，避免路径纂改 漏洞
            com.sunyard.cusprotect.entities.File fileInfo = universalService.getFileById(downfile.getId());
            String meansFictitiousName = fileInfo.getName();
            String meansName = fileInfo.getReal_name();
            File file = new File(downloadFilePath + File.separator + meansFictitiousName);
            if (file.exists()) {
//                String fileName = file.getName().toString();
                // firefox浏览器
                if (request.getHeader("User-Agent").toLowerCase().indexOf("firefox") > 0) {
                    meansName = new String(meansName.getBytes("UTF-8"), "ISO8859-1");
                } // IE浏览器
                else if (request.getHeader("User-Agent").toUpperCase().indexOf("MSIE") > 0) {
                    meansName = URLEncoder.encode(meansName, "UTF-8");
                }// 谷歌
                else if (request.getHeader("User-Agent").toUpperCase().indexOf("CHROME") > 0) {
                   // meansName = new String(meansName.getBytes("UTF-8"), "ISO8859-1");
                }
                //首先设置响应的内容格式是force-download，那么你一旦点击下载按钮就会自动下载文件了
                //response.setContentType("application/force-download");
                //通过设置头信息给文件命名，也即是，在前端，文件流被接受完还原成原文件的时候会以你传递的文件名来命名
                response.addHeader("Content-Disposition", "attachment;filename=" + meansName);
                response.setHeader("Cache-Control", "cache");
                response.setCharacterEncoding("UTF-8");
                //进行读写操作
                byte[] buffer = new byte[1024];
                FileInputStream fis = null;
                BufferedInputStream bis = null;
                try {
                    fis = new FileInputStream(file);
                    bis = new BufferedInputStream(fis);
                    OutputStream os = response.getOutputStream();
                    //从源文件中读
                    int i = bis.read(buffer);
                    while (i != -1) {
                        //写到response的输出流中
                        os.write(buffer, 0, i);
                        i = bis.read(buffer);
                    }
                    os.close();
                    return "下载成功";
                } catch (IOException e) {
                    e.printStackTrace();
                }finally {
                    if(bis != null){
                        try {
                            bis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if(fis != null){
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }

                }

            }
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return "下载失败";
    }

        download(row) {
        // 获取列表数据
        this.$http.post('file/download', row).then(res =>{
          fileDownload(res.data,res.headers,row.real_name)
        }).catch((err) => {
          console.log(err)
            this.$message.info('下载错误')
          })
      },

const CONTENT_TYPE = 'content-type'
const CONTENT_DISPOSITION = 'content-disposition'

export default function fileDownload(data, header, fileName) {
  const blob = new Blob([data], { type: header[CONTENT_TYPE] || 'application/octet-stream' })
  if (window.navigator.msSaveBlob) {
    // ie兼容
    window.navigator.msSaveBlob(blob)
  } else {
    const blobURL = (window.URL && window.URL.createObjectURL) ? window.URL.createObjectURL(blob) : window.webkitURL.createObjectURL(blob)
    const template = document.createElement('a')
    template.style.display = 'none'
    template.href = blobURL
    const download = fileName || decodeURIComponent(header[CONTENT_DISPOSITION].split('filename=').pop())
    template.setAttribute('download', download)
    if (typeof download === 'undefined') {
      template.setAttribute('target', '_blank')
    }
    document.body.append(template)
    template.click()
    setTimeout(_ => {
      document.body.removeChild(template)
      if (window.URL && window.URL.revokeObjectURL) {
        window.URL.revokeObjectURL(blobURL)
      } else {
        window.webkitURL.revokeObjectURL(blobURL)
      }
    }, 200)
  }
}

Answer 1

后端改成get自己在浏览器试下文件对不对，不对那就是读写时有问题，对的话那就是前端处理有问题，可以用saveAs这个库

Answer 2

后端试着把返回去掉（String换成void）