MissingServletRequestParameterException

Question

我将一个 formData 对象传递给我的 Spring 后端：

imageBanner(banner: File, bannerPath: string, id: number, callback: (response) => void){
    var formData = new FormData();
    formData.append('name', banner.name);
    console.log(formData.get('name'));
    formData.append('file', banner);
    console.log(formData.get('file'));

    this.sendPost("/upload/" + bannerPath, formData, response => {
        callback(response);
    });

}

控制台日志显示：

1.jpg 
File {name: "1.jpg", lastModified: 1496737372408, lastModifiedDate: Tue Jun 06 2017 10:22:52 GMT+0200 (W. Europe Daylight Time), webkitRelativePath: "", size: 38983…}

所以看起来 formData 有一些值。

在后端我有这个：

@RequestMapping(value="/rest/upload/localeventbanner", method=RequestMethod.POST, headers = "content-type!=multipart/form-data")
    public @ResponseBody String uploadFileHandler(@RequestParam("name") String name, @RequestParam("file") MultipartFile file) {

    if (!file.isEmpty()) {
        try {
            log("success");

            return "You successfully uploaded file=" + name;
        } catch (Exception e) {
            log("fail");
            return "You failed to upload";
        }
    } else {
        log("nope");
        return "You failed to upload " + name
                + " because the file was empty.";
    }
}

我在控制台中得到的回报是：

"{"timestamp":1502745177167,"status":400,"error":"Bad Request","exception":"org.springframework.web.bind.MissingServletRequestParameterException","message":"必需的字符串参数'name'不存在","path":"/beheerback/rest/upload/localeventbanner"}"

它说 name 不存在，但是当我在前端记录它时，它显示 name 存在于 formData 对象中。

Answer 1

尝试为名称和文件提供 required = false ，例如：

@RequestParam(value = "name", required = false, defaultValue = "defaultName") String name, @RequestParam(value = "file" , required = false, defaultValue = "defaultFile") MultipartFile file

然后检查您真正获得的值。此外，请在浏览器的开发模式下使用网络检查器检查发送的表单。