JS处理后端返回二进制流文件下载及乱码解决

axios({
  method: 'post',
  url: '/export',
})
.then(res => {
  // 假设 data 是返回来的二进制数据
  const data = res.data
  const url = window.URL.createObjectURL(new Blob([data], {type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"}))
  const link = document.createElement('a')
  link.style.display = 'none'
  link.href = url
  link.setAttribute('download', 'excel.xlsx')
  document.body.appendChild(link)
  link.click()
  document.body.removeChild(link)
})

axios({
  method: 'post',
  url: '/export',
  responseType: 'arraybuffer',
  // responseType: 'blob'
})
.then(res => {
  // 假设 data 是返回来的二进制数据
  const data = res.data
  const url = window.URL.createObjectURL(new Blob([data], {type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"}))
  const link = document.createElement('a')
  link.style.display = 'none'
  link.href = url
  link.setAttribute('download', 'excel.xlsx')
  document.body.appendChild(link)
  link.click()
  document.body.removeChild(link)
})

axios.interceptors.response.use(response => {
    const res = response.data
    // 判断响应数据类型是否 ArrayBuffer，true 则是下载文件接口，false 则是正常接口
    if (res instanceof ArrayBuffer) {
        const utf8decoder = new TextDecoder()
        const u8arr = new Uint8Array(res)
        // 将二进制数据转为字符串
        const temp = utf8decoder.decode(u8arr)
        if (temp.includes('{code:199999')) {
            Message({
                // 字符串转为 JSON 对象
                message: JSON.parse(temp).msg,
                type: 'error',
                duration: 5000,
            })
            return Promise.reject()
        }
    }
    // 正常类型接口，省略代码...
    return res
}, (error) => {
    // 省略代码...
    return Promise.reject(error)
})

const qryurl = `/offapi/liveaum/exportExcelData`;
    fetch(qryurl, {
      method: 'POST',
      credentials: 'include',
      headers: { Accept: 'application/json', 'Content-Type': 'application/json;charset=UTF-8' },
      body: JSON.stringify(params),
    }).then(response => {
      if (response.ok) {
        let downloadFileName = decodeURIComponent(response.headers.get('filename'));
        this.setState({ downloadFileName, downModalShow: true, iconLoading: false });
        response.blob().then(blob => {
          downBlob = blob;
        });
      }
    }).catch(function(err) {
      console.log(err);
      downBlob = null;
      message.warning('暂未查询到数据');
      this.setState({ iconLoading: false })
    });
// 导出文件
  handleOk = () => {
    const link = document.createElement('a');
    link.style.display = 'none';
    link.href = URL.createObjectURL(downBlob);
    link.download = `${this.state.downloadFileName}.xls`;
    document.body.appendChild(link);
    link.click();
    URL.revokeObjectURL(link.href);
    document.body.removeChild(link);
    message.success('下载成功');
    this.onModalclose();
  };