Java 如何从 BindingResult 获取控制器中的错误文本

How to get error text in controller from BindingResult

提问by Mike

I have an controller that returns JSON. It takes a form, which validates itself via spring annotations. I can get FieldError list from BindingResult, but they don't contain the text that a JSP would display in the tag. How can I get the error text to send back in JSON?

我有一个返回 JSON 的控制器。它采用一种形式，通过 spring 注释来验证自己。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。如何让错误文本以 JSON 形式发回？

@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 class is just a POJO

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...
}

Calling BindingResult.getAllErrors() returns an array of FieldError objects, but it doesn't have the actual errors.

调用 BindingResult.getAllErrors() 会返回一个 FieldError 对象数组，但它没有实际的错误。

采纳答案by Arthur Ronald

Disclaimer: I still do not use Spring-MVC 3.0

免责声明：我仍然不使用 Spring-MVC 3.0

But i think the same approach used by Spring 2.5 can fullfil your needs

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());
    }
}

I hope it can be useful to you

我希望它对你有用

UPDATE

更新

If you want to get the message provided by your resource bundle, you need a registered messageSource instance (It mustbe called messageSource)

如果你想获取你的资源包提供的消息，你需要一个注册的messageSource实例（必须叫messageSource）

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

Inject your MessageSource instance inside your View

在您的视图中注入您的 MessageSource 实例

@Autowired
private MessageSource messageSource;

And to get your message, do as follows

要获取您的消息，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);
    }
}

Your Validator should looks like

你的验证器应该看起来像

/**
  * 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);

回答by Hoàng Long

I met this problem recently, and found an easier way (maybe it's the support of Spring 3)

最近遇到这个问题，找到了一个更简单的方法（可能是Spring 3的支持）

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

There's no need to change/add the message source.

无需更改/添加消息源。

回答by splashout

BEAN XML:

豆 XML：

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

<bean id="messageAccessor" class="org.springframework.context.support.MessageSourceAccessor">
    <constructor-arg index="0" ref="messageSource"/>
</bean> 

---

---

JAVA:

爪哇：

for (FieldError error : errors.getFieldErrors()) {
    logger.debug(messageAccessor.getMessage(error));
}

NOTE:Calling Errors.getDefaultMessage() will not necessarily return the same message that is generated from the code + args. The defaultMessage is a separate value defined when calling the Errors.rejectValue() method. See Errors.rejectValue() API Here

注意：调用 Errors.getDefaultMessage() 不一定会返回从代码 + args 生成的相同消息。defaultMessage 是调用 Errors.rejectValue() 方法时定义的单独值。请参阅此处的 Errors.rejectValue() API

回答by Krzysiek

With Java 8 Streams

使用 Java 8 流

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

回答by Valerii Starovoitov

WebMvcConfigurerAdapter:

WebMvcConfigurerAdapter：

@Bean(name = "messageSourceAccessor")
public org.springframework.context.support.MessageSourceAccessor messageSourceAccessor() {
    return new MessageSourceAccessor( messageSource());
}

Controller:

控制器：

@Autowired
@Qualifier("messageSourceAccessor")
private MessageSourceAccessor           messageSourceAccessor;
...

StringBuilder sb = new StringBuilder();
for (ObjectError error : result.getAllErrors()) {
    if ( error instanceof FieldError) {
        FieldError fe = (FieldError) error;
        sb.append( fe.getField());
        sb.append( ": ");
    }
    sb.append( messageSourceAccessor.getMessage( error));
    sb.append( "<br />");
}