点击按钮通过AJAX MVC下载pdf文件

<button id="downloadBtn">下载PDF文件</button>

<script>
  document.getElementById("downloadBtn").addEventListener("click", function() {
    var xhr = new XMLHttpRequest();
    xhr.open("GET", "/download-pdf", true);
    xhr.responseType = "blob";
    xhr.onload = function() {
      if (xhr.status === 200) {
        var blob = new Blob([xhr.response], { type: "application/pdf" });
        var url = URL.createObjectURL(blob);
        var a = document.createElement("a");
        a.href = url;
        a.download = "file.pdf";
        a.click();
        URL.revokeObjectURL(url);
      }
    };
    xhr.send();
  });
</script>

@Controller
public class DownloadController {
  @GetMapping("/download-pdf")
  public ResponseEntity<byte[]> downloadPdf() throws IOException {
    // 生成pdf文件的逻辑，此处省略
    byte[] pdfData = generatePdf();

    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_PDF);
    headers.setContentDispositionFormData("attachment", "file.pdf");
    headers.setCacheControl("must-revalidate, post-check=0, pre-check=0");

    return new ResponseEntity<>(pdfData, headers, HttpStatus.OK);
  }
}