如何从BindingResult获取控制器中的错误文本

Question

我有一个返回JSON的控制器.它采用一种形式,通过弹簧注释验证自己.我可以从BindingResult获取FieldError列表,但它们不包含JSP将在标记中显示的文本.如何将错误文本发送回JSON？

@RequestMapping(method = RequestMethod.POST)
public
@ResponseBody
JSONResponse submit(@Valid AnswerForm answerForm, BindingResult result, Model model, HttpServletRequest request, HttpServletResponse response) {

    if (result.hasErrors()) {
        response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
        JSONResponse r = new JSONResponse();
        r.setStatus(JSONResponseStatus.ERROR);
        //HOW DO I GET ERROR MESSAGES OUT OF BindingResult??? 
    } else {
        JSONResponse r = new JSONResponse();
        r.setStatus(JSONResponseStatus.OK);
        return r;
    }

}

JSONREsponse类只是一个POJO

public class JSONResponse implements Serializable {
    private JSONResponseStatus status;
    private String error;
    private Map<String,String> errors;
    private Map<String,Object> data;

...getters and setters...
}

调用BindingResult.getAllErrors()返回FieldError对象的数组,但它没有实际的错误.

Answer 1

免责声明:我仍然不使用Spring-MVC 3.0

但我认为Spring 2.5使用的相同方法可以满足您的需求

for (Object object : bindingResult.getAllErrors()) {
    if(object instanceof FieldError) {
        FieldError fieldError = (FieldError) object;

        System.out.println(fieldError.getCode());
    }

    if(object instanceof ObjectError) {
        ObjectError objectError = (ObjectError) object;

        System.out.println(objectError.getCode());
    }
}

我希望它对你有用

UPDATE

如果要获取资源包提供的消息,则需要注册的messageSource实例(必须将其命名为messageSource)

<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
    <property name="basenames" value="ValidationMessages"/>
</bean>

在View中注入MessageSource实例

@Autowired
private MessageSource messageSource;

要获得您的信息,请执行以下操作

for (Object object : bindingResult.getAllErrors()) {
    if(object instanceof FieldError) {
        FieldError fieldError = (FieldError) object;

        /**
          * Use null as second parameter if you do not use i18n (internationalization)
          */

        String message = messageSource.getMessage(fieldError, null);
    }
}

你的验证器应该是这样的

/**
  * Use null as fourth parameter if you do not want a default message
  */
errors.rejectValue("<FIELD_NAME_GOES_HERE>", "answerform.questionId.invalid", new Object [] {"123"}, null);

Answer 2

我最近遇到了这个问题,并找到了一种更简单的方法(也许是Spring 3的支持)

    List<FieldError> errors = bindingResult.getFieldErrors();
    for (FieldError error : errors ) {
        System.out.println (error.getObjectName() + " - " + error.getDefaultMessage());
    }

无需更改/添加消息源.

Answer 3

使用Java 8 Streams

bindingResult
.getFieldErrors()
.stream()
.forEach(f -> System.out.println(f.getField() + ": " + f.getDefaultMessage()));