Java 使用Spring Boot+；上载时Excel文件损坏；角JS

我正在尝试使用angular js+spring boot上传一个excel文件。文件已成功上载，但文件似乎已损坏。我无法打开文件。这是我的密码

index.html

<p align="right">
    <input type = "file" id="file" name="file"/>
    <button ng-click="uploadFile()">Upload</button>
</p>

Controller.java

@RequestMapping(value = "/uploadAsExcel", method = RequestMethod.POST)
@ResponseBody
public ResponseEntity<?> uploadFile(@RequestParam("uploadfile") MultipartFile uploadfile) {

    try {
        // Get the filename and build the local file path
        String filename = uploadfile.getOriginalFilename();
        String contentType = uploadfile.getContentType();
        System.out.println("ContentType: "+contentType);
        String filepath = "C:\\Users\\user122\\Documents\\MyFiles\\"+filename;

        //Save the file locally
        BufferedOutputStream stream =
                new BufferedOutputStream(new FileOutputStream(new File(filepath)));
        stream.write(uploadfile.getBytes());
        stream.close();
    }
    catch (Exception e) {
        System.out.println(e.getMessage());
        return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
    }

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

@Bean
public CommonsMultipartResolver multipartResolver() {
    CommonsMultipartResolver resolver=new CommonsMultipartResolver();
    //resolver.setDefaultEncoding("utf-8");
    resolver.setMaxUploadSize(-1);
    return resolver;
}

Excel文件上传成功，但当我打开文件时，它显示“文件已损坏”。基本上，我需要使用excel API读取excel文件并执行一些操作

你能请任何人帮忙吗

谢谢， 卡提克

@Bean
public CommonsMultipartResolver multipartResolver() {
    CommonsMultipartResolver resolver=new CommonsMultipartResolver();
    //resolver.setDefaultEncoding("utf-8");
    resolver.setMaxUploadSize(-1);
    return resolver;
}