java返回Spring MVC Post请求的JSON响应

Question

我有下面的控制器方法，它是上传文件到我的服务器。我想返回Plupload状态的JSON。然而，响应似乎是作为分派而不是json@ResponseBy发送回来的。有什么想法吗

    private static final String RESP_SUCCESS = "{\"jsonrpc\" : \"2.0\", \"result\" : \"success\", \"id\" : \"id\"}";
    private static final String RESP_ERROR = "{\"jsonrpc\" : \"2.0\", \"error\" : {\"code\": 101, \"message\": \"Failed to upload file.\"}, \"id\" : \"id\"}";

    @RequestMapping(method = RequestMethod.POST)
    public String uploadItem(@RequestBody MultipartFile file,
                             @RequestParam String name,
                             @RequestParam(required = false, defaultValue = "-1") int chunks,
                             @RequestParam(required = false, defaultValue = "-1") int chunk) {
        Media media = new Media();
        try {
            Path path = Paths.get("/Users/username/Desktop/Test", file.getOriginalFilename());
            media.setContentType(file.getContentType());
            media.setFileName(file.getOriginalFilename());
            media.setFileSize(file.getSize());
            media.setFilePath(path.toString());
            if (media.getContentType().contains("image")) {
                Image image = new Image();
                image.setImagePath(path.toString());
                imageDao.save(image);
            }
            byte[] bytes = file.getBytes();
            Files.write(path, bytes, StandardOpenOption.CREATE);
            mediaDao.save(media);
            return RESP_SUCCESS;
        } catch (IOException e) {
            e.printStackTrace();

        }
        return RESP_ERROR;
    }
}

引发以下错误：

WARN - No mapping found for HTTP request with URI [/{"jsonrpc" : "2.0", "result" : "success", "id" : "id"}] in DispatcherServlet with name 'cr'

Answer 1

方法的返回类型必须为String，它与注释（结果将用作响应主体）是分开的

@ResponseBody不是返回类型，也不是类型！这是一个注释

文本内容&；上一个答案中提出的语法是严重错误的，尽管我在其他方面对此表示赞赏

我的建议是：

@RequestMapping(method = RequestMethod.POST)
@ResponseBody 
public String uploadItem(@RequestBody MultipartFile file,
                         @RequestParam String name,
                         @RequestParam(required = false, defaultValue = "-1") int chunks,
                         @RequestParam(required = false, defaultValue = "-1")

Answer 2

我认为你的方法应该用@ResponseBody注释

@RequestMapping(method = RequestMethod.POST)
@ResponseBody
public  String uploadItem(@RequestBody MultipartFile file,
                             @RequestParam String name,
                             @RequestParam(required = false, defaultValue = "-1") int chunks,
                             @RequestParam(required = false, defaultValue = "-1")

以下是Spring检查Json转换的方式：

• Jackson库存在于项目类路径中
• 已启用mvc:注释驱动
• 用@ResponseBody注释的返回方法

Spring将自动处理JSON转换