大佬们，我想要做的是下载限速。公司将软件上传，对其下载网速进行限速。现在限速下载接口算是写好了，前端访问后台页面并将文件下载下来我不会写。问的公司有经验的一个后端，现在现在效果是页面上显示访问成功，后台代码显示下载成功。但是找不到下载的文件在哪。请大佬们帮我看看前端代码怎么改。我第一次写代码，前端不会，后端不熟，呜呜呜，大佬们帮帮忙把。
下边是下载的代码
@Controller
@RequestMapping("file")
public class DownloadFileController {

@PostMapping("/limit")

public void limitDownloadFile(String file, HttpServletResponse response) throws IOException {
    System.out.println("download file");

    if (file == null) {
        file = "C:/Users/jhsoft/Desktop/test.txt";

    }

    File downloadFile = new File(file);
    System.out.println(downloadFile.getName());

    FileInputStream fileInputStream = new FileInputStream(downloadFile);

    response.setContentType("application/x-msdownload;");

    response.setHeader("Content-disposition", "attachment; filename=" + new String(downloadFile.getName()

            .getBytes("utf-8"), "ISO8859-1"));

    response.setHeader("Content-Length", String.valueOf(downloadFile.length()));

    ServletOutputStream outputStream = null;

    try {
        LimitInputStream limitInputStream = new LimitInputStream(fileInputStream, new BandwidthLimiter(1024));

        long beginTime = System.currentTimeMillis();

        outputStream = response.getOutputStream();
        System.out.println("outputStream:");
        System.out.println(outputStream.toString());

        byte[] bytes = new byte[1024];

        int read = limitInputStream.read(bytes, 0, 1024);

        while (read != -1) {
            outputStream.write(bytes);

            read = limitInputStream.read(bytes, 0, 1024);

        }

        System.out.println(System.currentTimeMillis() - beginTime);

    } finally {
        fileInputStream.close();

        if (outputStream != null) {
            outputStream.close();

        }

        System.out.println("download success!");

    }

}

}

这是前端内容：
<script type="text/javascript">
//页面一开始加载的时候会先执行这个方法里的东西
$(function (){
$.ajax({
type: "post",
url: "/file/limit",
data: {
"file": "F:/项目restaurant/restaurant/restaurant/sql/text.txt"
},
success: function(res) {
console.log("访问成功");
}
});
});