java当metod返回ResponseEntry<Resource>抛出错误时，如何返回ModelandView？

Question

我有以下方法

@GetMapping("/{fileName}")
public Object downloadFile(@PathVariable String fileName) {
    // Load file from database
    errors.clear();

    DBFile dbFile;

    try {
        dbFile = dBFileStorageService.getFileByName(fileName);

    } catch (MyFileNotFoundException ex) {
        logger.info("File has not been found.");
        errors.add(ex.getMessage());

        return new ModelAndView("redirect:/");
    }
    logger.info("Delivering file");
    return ResponseEntity.ok()
            .contentType(MediaType.parseMediaType(dbFile.getFileType()))
            .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + dbFile.getFileName() + "\"")
            .body(new ByteArrayResource(dbFile.getData()));

}

如果可以返回文件，我想返回ResponseEntity<Resource>，而不是返回Object，否则返回ModelAndView("redirect:/")

我试过：

HttpHeaders headers = new HttpHeaders();
headers.add("Location", "/member/uploadImage");    
return new ResponseEntity<>(headers,HttpStatus.FOUND);

但我没有重定向，而是收到一条消息，说我试图下载的文件已损坏。 总结一下，我想将方法签名更改为：

public ResponseEntiry<Resource> downloadFile(@PathVariable String fileName)  

Answer 1

关于通过ResponseEntity返回文件的第一个问题，这里已经回答了： Return file from Spring @Controller having OutputStream

同意wwith@chrylis，正如他所建议的，在发生异常时，最好的方法是抛出异常，并使用@ExceptionHandler方法注释在sprin @ControllerAdvice类中处理它

@ControllerAdvice
class GlobalControllerExceptionHandler {
    @ResponseStatus(HttpStatus.CONFLICT)  // 409 or according to your need any code
    @ExceptionHandler(Exception.class)
    protected ModelAndView unhandledExceptionHandler(Exception ex){
        System.out.println("handling exception here!!!");
        ModelAndView mv = new ModelAndView();
        mv.setViewName("errorView");
        mv.addObject("ERROR", "ERROR OCCURRED REDIRECTED "+ex.getMessage());
        return mv;
    }
}

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