使用自定义名称导出文件

Question

我想实现这个用于从 Spring BE 导出数据的代码示例。

@GetMapping("export/{ids}")
    public void export(HttpServletResponse response, @PathVariable List<Integer> ids) {

        List<Transactions> transactions = (List<Transactions>) transactionService.findAll(ids);
        List<TransactionExcelEntry> entries = transactions.stream().map(payment_transaction_mapper::toExcel).collect(Collectors.toList());

        List<String> headers = Arrays.asList("Id", "Name", "Type", "Created at");
        try {
            response.addHeader("Content-disposition", "attachment; filename=Transactions.xlsx");
            response.setContentType("application/vnd.ms-excel");
            new SimpleExporter().gridExport(headers, entries, "id, name", response.getOutputStream());
            response.flushBuffer();

        } catch (IOException ex) {
            LOG.debug("parsing of transactions failed");
        }
    }

导出按钮：

<button class="dropdown-item" (click)="export()">XLS</button>

导出功能：

export() {
    var newPagination = new Pagination();
    newPagination.size = this.pagination.size * this.pagination.total
    this.transactionService.search(newPagination, this.formGroup.value)
        .subscribe(result => {
            this.formGroup.enable();
            const query = result.content.map(t => t.id).join(',');
            this.transactionService.exportRows(query).subscribe(data => {
                const a = document.createElement('a');

                a.href = window.URL.createObjectURL(data);
                a.download = 'export.xls';
                a.click();
            });
        }, (error) => {
            this.formGroup.enable();
        });
  }

exportRows(query) {
    return this.http.get(`/api/transactions/export`, { responseType: 'blob' });
}

我想生成文件名到Java BE 并从Angular FE 下载。如何实现此功能？

Answer 1

您可以通过访问响应 header 并检索 Content-Disposition.

来检索 blob 的文件名

为此，请通过提供额外的选项 observe: 'response'.

稍微更改您的 HttpClient.get 调用

为了清楚起见，我们创建了一个专用的 ExportResponse 来仅向我们的 component/or 其他服务方法公开需要的数据：

export type ExportResponse = {
  blob: Blob,
  fileName: string
}

exportRows 检索 Response Headers :

exportRows(query): ExportResponse {
  return this.http.get(`/api/transactions/export`, { 
    observe: 'response',
    responseType: 'blob' 
  }.pipe(
    map(response => {
      const contentDisposition = response.headers.get('content-disposition');
      return {
        blob: response.body,
        fileName: getContentDispositionFileName(contentDisposition)
      }
    })
  );
}

getContentDispositionFileName方法负责从收到的header中提取文件名：

getContentDispositionFileName(contentDisposition: string) {
  let filename = 'default-file-name';

  var filenameRegex = /filename[^;=\n]*=((['"]).*?|[^;\n]*)/;
  var matches = filenameRegex.exec(contentDisposition);
  if (matches != null && matches[1]) {
    filename = matches[1].replace(/['"]/g, '');
  }

  return filename;
}

此 RegExp 模式来自 Winter Soldier's answer，并提取了文件名的部分。

然后你可以在初始方法中使用ExportResponse:

this.transactionService.exportRows(query).subscribe(response => {
  const a = document.createElement('a');
  a.href = window.URL.createObjectURL(response.blob);
  a.download = response.fileName;
  a.click();
});

重要提示

如果您启用了 CORS，请小心允许您的后端发送并授权您的 frond-end 访问 Content-Disposition header.

为此，请在您的回复中添加 Access-Control-Expose-Headers: Content-Disposition。

response.addHeader(HttpHeaders.ACCESS_CONTROL_EXPOSE_HEADERS, HttpHeaders.CONTENT_DISPOSITION);

Answer 2

如果你想自动生成文件名可以试试下面的方法

export(filename) {
  this.transactionService.search(newPagination, this.formGroup.value)
        .subscribe(result => {
            this.formGroup.enable();
            const timeStamp: number = new Date().getTime();
            const query = result.content.map(t => t.id).join(',');
            this.transactionService.exportRows(query).subscribe(data => {
                const a = document.createElement('a');

                a.href = window.URL.createObjectURL(data);
                a.download = `${fileName}-${timeStamp}.xls`;
                a.click();
            });
        }, (error) => {
            this.formGroup.enable();
        });
}

单击按钮可以发送文件名，或者通过服务调用可以从服务器获取文件名

<button class="dropdown-item" (click)="export('Transaction')">XLS</button>

使用自定义名称导出文件

Export file with custom name

spring

angular

angular7

angular8

重要提示