springboot+vue+elementUI项目中，写一个从路径10.0.90.52/oath下载PDF文件的API

可以使用Java中的HttpClient类来实现从指定路径下载PDF文件的API。以下是示例代码：

@RequestMapping("/download")
public ResponseEntity<byte[]> downloadPDF() throws IOException {
    CloseableHttpClient httpClient = HttpClients.createDefault();
    HttpGet httpGet = new HttpGet("http://10.0.90.52/oath");
    CloseableHttpResponse response = httpClient.execute(httpGet);
    HttpEntity entity = response.getEntity();
    byte[] bytes = EntityUtils.toByteArray(entity);
    HttpHeaders headers = new HttpHeaders();
    headers.add("Content-Disposition", "attachment;filename=" + "file.pdf");
    HttpStatus status = HttpStatus.OK;
    ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, headers, status);
    return responseEntity;
}

这个API将会提供一个/download的接口，当调用该接口时，会返回一个名为file.pdf的PDF文件。