@ControllerAdvice
public class ValidParamExceptionHandler {
    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    public Map<String, Object> allExceptionHandler(Exception e){
         Map<String, Object> map = new HashMap<>(2);
         if(e instanceof BindException) {
            BindException ex = (BindException)e;
            BindingResult bindingResult = ex.getBindingResult();
            StringBuilder errMsg = new StringBuilder(bindingResult.getFieldErrors().size() * 16);
            errMsg.append("Invalid request:");
            for (int i = 0 ; i < bindingResult.getFieldErrors().size() ; i++) {
                if(i > 0) {
                    errMsg.append(",");
                }
                FieldError error = bindingResult.getFieldErrors().get(i);
                errMsg.append(error.getField()+":"+error.getDefaultMessage());
            }
            map.put("errcode", 500);
            map.put("errmsg", errMsg.toString());
        
        }
        else {    
            map.put("errcode", 500);
            map.put("errmsg", e.getMessage());
        }
        return map;
    }

/**
 * 通用異常攔截處理類（通過(guò)切面的方式默認(rèn)攔截所有的controller異常）
 */
@Slf4j
@RestControllerAdvice
public class CommonExceptionHandler {
 
    /**
     * 對(duì)運(yùn)行時(shí)異常進(jìn)行統(tǒng)一異常管理方法
     * @param e
     * @return
     */
    @ExceptionHandler(FlyException.class) // FlyException類繼承于RuntimeException
    public ResponseEntity<Map<String, Object>> handlerException(FlyException e) {
        Map<String, Object> result = new HashMap<>(1);
        result.put("message", e.getMessage());
        return ResponseEntity.status(e.getCode()).body(result);
    }

  @PostMapping
    public ResponseEntity save(@Valid BrandCreateRequestDto dto, BindingResult bindingResult) {
        // 判斷是否含有校驗(yàn)不匹配的參數(shù)錯(cuò)誤
        if (bindingResult.hasErrors()) {
            // 獲取所有字段參數(shù)不匹配的參數(shù)集合
            List<FieldError> fieldErrorList = bindingResult.getFieldErrors();
            Map<String, Object> result = new HashMap<>(fieldErrorList.size());
            fieldErrorList.forEach(error -> {
                // 將錯(cuò)誤參數(shù)名稱和參數(shù)錯(cuò)誤原因存于map集合中
                result.put(error.getField(), error.getDefaultMessage());
            });
            return ResponseEntity.status(HttpStatus.BAD_REQUEST.value()).body(result);
        } 
        brandService.save(dto);
        return ResponseEntity.status(HttpStatus.CREATED.value()).build();
    }

/**
 * Exception to be thrown when validation on an argument annotated with {@code @Valid} fails.
 *
 * @author Rossen Stoyanchev
 * @since 3.1
 */
@SuppressWarnings("serial")
public class MethodArgumentNotValidException extends Exception { 
 private final MethodParameter parameter; 
 private final BindingResult bindingResult; 
 
 /**
  * Constructor for {@link MethodArgumentNotValidException}.
  * @param parameter the parameter that failed validation
  * @param bindingResult the results of the validation
  */
 public MethodArgumentNotValidException(MethodParameter parameter, BindingResult bindingResult) {
  this.parameter = parameter;
  this.bindingResult = bindingResult;
 }

/**
 * 對(duì)方法參數(shù)校驗(yàn)異常處理方法
 */
@ExceptionHandler(MethodArgumentNotValidException.class)
public ResponseEntity<Map<String, Object>> handlerNotValidException(MethodArgumentNotValidException exception) {
    log.debug("begin resolve argument exception");
    BindingResult result = exception.getBindingResult();
    Map<String, Object> maps;
 
    if (result.hasErrors()) {
        List<FieldError> fieldErrors = result.getFieldErrors();
        maps = new HashMap<>(fieldErrors.size());
        fieldErrors.forEach(error -> {
            maps.put(error.getField(), error.getDefaultMessage());
        });
    } else {
        maps = Collections.EMPTY_MAP;
    } 
    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(maps);
}

public class ModelAttributeMethodProcessor implements HandlerMethodArgumentResolver, HandlerMethodReturnValueHandler {
 
...
 public final Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
   NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
        ...
        Object attribute = null;
  BindingResult bindingResult = null;
 
  if (mavContainer.containsAttribute(name)) {
   attribute = mavContainer.getModel().get(name);
  }
  else {
   // Create attribute instance
   try {
    attribute = createAttribute(name, parameter, binderFactory, webRequest);
   }
   catch (BindException ex) {
    if (isBindExceptionRequired(parameter)) {
     // No BindingResult parameter -> fail with BindException
     throw ex;
    }
    // Otherwise, expose null/empty value and associated BindingResult
    if (parameter.getParameterType() == Optional.class) {
     attribute = Optional.empty();
    }
    bindingResult = ex.getBindingResult();
   }
  } 
        //進(jìn)行參數(shù)綁定和校驗(yàn)
  if (bindingResult == null) {
   // 對(duì)屬性對(duì)象的綁定和數(shù)據(jù)校驗(yàn);
   // 使用構(gòu)造器綁定屬性失敗時(shí)跳過(guò).
   WebDataBinder binder = binderFactory.createBinder(webRequest, attribute, name);
           
   if (binder.getTarget() != null) {
    if (!mavContainer.isBindingDisabled(name)) {
     bindRequestParameters(binder, webRequest);
    }
                // 對(duì)綁定參數(shù)進(jìn)行校驗(yàn)，校驗(yàn)失敗，將其結(jié)果信息賦予bindingResult對(duì)象
    validateIfApplicable(binder, parameter);
                // 如果獲取參數(shù)綁定的結(jié)果中包含錯(cuò)誤的信息則拋出異常
    if (binder.getBindingResult().hasErrors() && isBindExceptionRequired(binder, parameter)) {
     throw new BindException(binder.getBindingResult());
    }
   }
   // Value type adaptation, also covering java.util.Optional
   if (!parameter.getParameterType().isInstance(attribute)) {
    attribute = binder.convertIfNecessary(binder.getTarget(), parameter.getParameterType(), parameter);
   }
   bindingResult = binder.getBindingResult();
  }
 
  // Add resolved attribute and BindingResult at the end of the model
  Map<String, Object> bindingResultModel = bindingResult.getModel();
  mavContainer.removeAttributes(bindingResultModel);
  mavContainer.addAllAttributes(bindingResultModel); 
  return attribute;
}

/**
 * Thrown when binding errors are considered fatal. Implements the
 * {@link BindingResult} interface (and its super-interface {@link Errors})
 * to allow for the direct analysis of binding errors.
 *
 * <p>As of Spring 2.0, this is a special-purpose class. Normally,
 * application code will work with the {@link BindingResult} interface,
 * or with a {@link DataBinder} that in turn exposes a BindingResult via
 * {@link org.springframework.validation.DataBinder#getBindingResult()}.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Rob Harrop
 * @see BindingResult
 * @see DataBinder#getBindingResult()
 * @see DataBinder#close()
 */
@SuppressWarnings("serial")
public class BindException extends Exception implements BindingResult { 
 private final BindingResult bindingResult; 
 
 /**
  * Create a new BindException instance for a BindingResult.
  * @param bindingResult the BindingResult instance to wrap
  */
 public BindException(BindingResult bindingResult) {
  Assert.notNull(bindingResult, "BindingResult must not be null");
  this.bindingResult = bindingResult;
 }

/**
 * 對(duì)方法參數(shù)校驗(yàn)異常處理方法
 */
@ExceptionHandler(BindException.class)
public ResponseEntity<Map<String, Object>> handlerNotValidException(BindException exception) {
    log.debug("begin resolve argument exception");
    BindingResult result = exception.getBindingResult();
    Map<String, Object> maps;
 
    if (result.hasErrors()) {
        List<FieldError> fieldErrors = result.getFieldErrors();
        maps = new HashMap<>(fieldErrors.size());
        fieldErrors.forEach(error -> {
            maps.put(error.getField(), error.getDefaultMessage());
        });
    } else {
        maps = Collections.EMPTY_MAP;
    } 
    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(maps);
}

/**
     * 對(duì)方法參數(shù)校驗(yàn)異常處理方法(僅對(duì)于表單提交有效，對(duì)于以json格式提交將會(huì)失效)
     * 如果是表單類型的提交，則spring會(huì)采用表單數(shù)據(jù)的處理類進(jìn)行處理（進(jìn)行參數(shù)校驗(yàn)錯(cuò)誤時(shí)會(huì)拋出BindException異常）
     */
    @ExceptionHandler(BindException.class)
    public ResponseEntity<Map<String, Object>> handlerBindException(BindException exception) {
        return handlerNotValidException(exception);
    }
 
    /**
     * 對(duì)方法參數(shù)校驗(yàn)異常處理方法(前端提交的方式為json格式出現(xiàn)異常時(shí)會(huì)被該異常類處理)
     * json格式提交時(shí)，spring會(huì)采用json數(shù)據(jù)的數(shù)據(jù)轉(zhuǎn)換器進(jìn)行處理（進(jìn)行參數(shù)校驗(yàn)時(shí)錯(cuò)誤是拋出MethodArgumentNotValidException異常）
     */
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<Map<String, Object>> handlerArgumentNotValidException(MethodArgumentNotValidException exception) {
        return handlerNotValidException(exception);
    }
 
    public ResponseEntity<Map<String, Object>> handlerNotValidException(Exception e) {
        log.debug("begin resolve argument exception");
        BindingResult result;
        if (e instanceof BindException) {
            BindException exception = (BindException) e;
            result = exception.getBindingResult();
        } else {
            MethodArgumentNotValidException exception = (MethodArgumentNotValidException) e;
            result = exception.getBindingResult();
        }
 
        Map<String, Object> maps;
        if (result.hasErrors()) {
            List<FieldError> fieldErrors = result.getFieldErrors();
            maps = new HashMap<>(fieldErrors.size());
            fieldErrors.forEach(error -> {
                maps.put(error.getField(), error.getDefaultMessage());
            });
        } else {
            maps = Collections.EMPTY_MAP;
        }
         return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(maps); 
    }