java - Spring在 Controller 类中初始化Errors接口(interface)

Question

我在项目中运行的一些验证遇到问题。我试图验证我在 Controller 中创建的对象内的一些参数，首先接收一个字符串。

@RequestMapping(value = "/publicar", method = { RequestMethod.GET, RequestMethod.POST }, produces = MediaType.APPLICATION_XML_VALUE)
@ResponseBody
public ApiPubPortalPublicarOut publicar(@RequestParam(value = PARAM_XML) String xml, Locale locale) {
            //This object is my return, it creates an XML with the validation.
            ApiPubPortalPublicarOut xmlTaxOut = new ApiPubPortalPublicarOut();
            Errors result = null; //Here is the problem

            //validate incoming xml is empty
            if ((xml == null) || (xml.length() == 0)) {
                xmlTaxOut.setDescription("xml is Empty!");
                return xmlTaxOut;
            }else{
                try{
                    //I transform the xml into an object
                    JAXBContext jc = JAXBContext.newInstance(ApiPubPortalPublicarPortal.class);
                    Unmarshaller unmarshaller = jc.createUnmarshaller();
                    StreamSource streamSource = new StreamSource(new StringReader(xmlEntrada));
                    JAXBElement<ApiPubPortalPublicarPortal> je = unmarshaller.unmarshal(streamSource, ApiPubPortalPublicarPortal.class);

                    //Here is the validation method.
                     parsingPublicacion(je.getValue(), result, locale);
                     if(result.hasErrors()){
                        xmlTaxOut.setDescription(result.getAllErrors().toString());
                        return xmlTaxOut;
                     }
                }catch(Exception){
                    xmlTaxOut.setDescription("Error parsing!");
                    return xmlTaxOut;
                }
            }
        }

这是我的 Controller ，正如您所看到的，我尝试将字符串转换为对象，然后调用方法 parsingPublicacion 来进行验证。

主要问题是我无法初始化我的 Errors 参数，因为它是一个接口(interface)，有人知道我如何管理此验证吗？

这是 mi validator 方法。

private void parsingPublicacion(ApiPubPortalPublicarPortal portalPublicado,  Errors e, Locale locale) {
    ApiPubPortalPublicarPortal pubPortal = portalPublicado;

    ValidationUtils.rejectIfEmptyOrWhitespace(e, "name", "name.empty"));
    if (pubPortal.getNombre().length() > 50){
        e.rejectValue("name", "name.oversize");
    }

    ValidationUtils.rejectIfEmptyOrWhitespace(e, "idLanguage.empty");
    if ((pubPortal.getIdPortal() == 0)){
        e.rejectValue("idLanguage", "idLanguage.zero"));
    }

}

我无法从方法中调用错误，因为我只允许调用 Controller 中的特定参数。

Answer 1

Edit 2 Since you don't have a model attribute you need to use a concrete class that implements Errors. BeanPropertyBindingResult is such one.

您可以按如下方式使用BeanPropertyBindingResult

@RequestMapping(value = "/publicar", method = { RequestMethod.GET, RequestMethod.POST }, produces = MediaType.APPLICATION_XML_VALUE)
@ResponseBody
public ApiPubPortalPublicarOut publicar(@RequestParam(value = PARAM_XML) String xml, Locale locale) {
    //This object is my return, it creates an XML with the validation.
    ApiPubPortalPublicarOut xmlTaxOut = new ApiPubPortalPublicarOut();


    //validate incoming xml is empty
    if ((xml == null) || (xml.length() == 0)) {
        xmlTaxOut.setDescription("xml is Empty!");
        return xmlTaxOut;
    }else{
        try{
            //I transform the xml into an object
            JAXBContext jc = JAXBContext.newInstance(ApiPubPortalPublicarPortal.class);
            Unmarshaller unmarshaller = jc.createUnmarshaller();
            StreamSource streamSource = new StreamSource(new StringReader(xmlEntrada));
            JAXBElement<ApiPubPortalPublicarPortal> je = unmarshaller.unmarshal(streamSource, ApiPubPortalPublicarPortal.class);

            // Using concrete implementation of error interface
            BeanPropertyBindingResult result = new BeanPropertyBindingResult(je.getValue(), "apiPubPortal");


            //Here is the validation method.
            parsingPublicacion(je.getValue(), result, locale);
            if(result.hasErrors()){
                xmlTaxOut.setDescription(result.getAllErrors().toString());
                return xmlTaxOut;
            }
        }catch(Exception){
            xmlTaxOut.setDescription("Error parsing!");
            return xmlTaxOut;
        }
    }
}

Edit 1 You can use Error interface as method parameter too. And Spring will still populate an implementation.

使用BindigResults作为方法参数并在错误的地方使用它。 Spring 将自动为您填充一个实现。

@RequestMapping(value = "/publicar", method = { RequestMethod.GET, RequestMethod.POST }, produces = MediaType.APPLICATION_XML_VALUE)
@ResponseBody
public ApiPubPortalPublicarOut publicar(@RequestParam(value = PARAM_XML) String xml,
                                        BindingResult result, Locale locale) {
            //This object is my return, it creates an XML with the validation.
            ApiPubPortalPublicarOut xmlTaxOut = new ApiPubPortalPublicarOut();
            // Use BindingResult in places of erros


        }

BindingResult 扩展了 Errors，因此您将拥有 error 的功能。

https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#mvc-ann-arguments