[JavaScript知识库]SpringBoot ResponseEntity + axios 下载文件

后端：

// 设置响应头
HttpHeaders headers = new HttpHeaders();
// 文件名URLEncoder.encode(fileName,"UTF-8") 防止中文乱码
headers.setContentDispositionFormData("attachment", URLEncoder.encode(fileName,"UTF-8"));
headers.setContentLength(bytes.length);
headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
headers.set("fileName", URLEncoder.encode(fileName,"UTF-8"));
// setAccessControlExposeHeaders 设置这个前端才能取到
headers.setAccessControlExposeHeaders(Arrays.asList(HttpHeaders.CONTENT_DISPOSITION,
        HttpHeaders.CONTENT_LENGTH, HttpHeaders.CONTENT_TYPE));
// bytes 文件字节数组
return ResponseEntity.status(HttpStatus.SC_OK).headers(headers).body(bytes);

前端：

    /**
     * url: 下载地址
     * defaultFileName: 默认文件名（若前端已知文件名）
     * data: 请求参数
     */
    downloadFile(url, defaultFileName, data) {
      axios({
        url,
        method: "post",
        responseType: "blob",
        data,
      }).then((response) => {
        let fileName;
        const { data: body } = response;
        // 这里要注意 content-disposition全小写
        const contentDisposition = response.headers["content-disposition"];
        if (contentDisposition) {
          // filename 同样全小写
          var filenameRegex = /filename[^;=\n]*=((['"]).*?\2|[^;\n]*)/;
          var matches = filenameRegex.exec(contentDisposition);
          if (matches != null && matches[1]) {
            fileName = matches[1].replace(/['"]/g, "");
          }
        }

        if (body) {
          let file = new Blob([body], {
            type: "application/octet-stream",
          });
          var downloadElement = document.createElement("a");
          var href = window.URL.createObjectURL(file);
          downloadElement.href = href;
          downloadElement.download = decodeURIComponent(fileName || defaultFileName);
          document.body.appendChild(downloadElement);
          downloadElement.click();
          document.body.removeChild(downloadElement);
          window.URL.revokeObjectURL(href);
        } else {
          // 下载失败的处理
        }
      });
    },