Spring类AbstractMessageConverterMethodProcessor上的NullPointerException

Question

我正在创建一个验证字段的服务。如果该字段不符合我的规则，我会抛出一个ResourceBusinessException，这是我创建的一个类，用于处理不可处理的实体。但是，当抛出此异常时，Spring在类AbstractMessageConverterMethodProcessor上抛出NullPointerException。

首先，我的Spring版：

<spring-framework-version>4.2.6.RELEASE</spring-framework-version>

 /**
 * @param MyType
 * @return
 */
@ApiOperation(value = "", notes = "", authorizations = { @Authorization(value = ApplicationSwaggerConfig.securityOAuth2, scopes = { @AuthorizationScope(scope = WRITE_SCOPE, description = WRITE_DESCRIPTION) }) })
@ApiResponses(value = { @ApiResponse(code = 200, message = "OK"), @ApiResponse(code = 201, message = "Created"), @ApiResponse(code = 401, message = "Unauthorized"),
@ApiResponse(code = 403, message = "Forbidden"), @ApiResponse(code = 404, message = "Not Found"), @ApiResponse(code = 422, message = "Unprocessable Entity") })
@RequestMapping(value = "/xpto", method = POST, produces = { APPLICATION_XML_VALUE, APPLICATION_JSON_VALUE })
public ResponseEntity<Void> saveXPTO(@RequestBody MyType myType) {
    Long tenantId = 1L;
    MyClass myObject = service.findMyClass(tenantId, empresaType.getAttribute());
    MyOtherClass myOtherObject= this.applyForOne(myObject);
    PreconditionsRest.checkCondition(false, "ERROR!!"); // This is where I'm forcing an error.
    contribuinteService.saveMyOtherObject(myOtherObject);
    return new ResponseEntity<Void>(new HttpHeaders(), CREATED);
}

/**
 * Check condition.
 *
 * @param condition O(a)(s) condition
 */
public static void checkCondition(boolean condition, String message){
    if (!condition) {
        throw new ResourceBusinessException(message);
    }
}

public class ResourceBusinessException extends RuntimeException{

private static final long serialVersionUID = 1L;


private ErrorMessage errorMessage;


public ResourceBusinessException() {
    super();
}


public ResourceBusinessException(String message, Throwable cause,boolean enableSuppression, boolean writableStackTrace) {
    super(message, cause, enableSuppression, writableStackTrace);
}


public ResourceBusinessException(String message, Throwable cause) {
    super(message, cause);
}


public ResourceBusinessException(String message) {
    super(message);
}


public ResourceBusinessException(Throwable cause) {
    super(cause);
}


public ResourceBusinessException(ErrorMessage errorMessage){
    super(errorMessage.getDetail());
    this.errorMessage = errorMessage;
}


public ErrorMessage getErrorMessage() {
    return errorMessage;
}

}

我的ResourceBusinessExceptionHandler

public class ResourceBusinessExceptionHandler extends ErrorMessageRestExceptionHandler<ResourceBusinessException>{


private static final Logger LOGGER = LoggerFactory.getLogger(ResourceBusinessExceptionHandler.class);

private ErrorMessage errorMessage;

public ResourceBusinessExceptionHandler() {
    super(UNPROCESSABLE_ENTITY);
}


@Override
public ErrorMessage createBody(ResourceBusinessException ex, HttpServletRequest req) {
    LOGGER.debug("ResourceBusinessExceptionHandler - Started");
    ErrorMessage tmpl = super.createBody(ex, req);
    ValidationErrorMessage msg = new ValidationErrorMessage(tmpl);
    errorMessage=ex.getErrorMessage();
    if(errorMessage==null){
        errorMessage = new ErrorMessage();
    }
    msg.setType(ResourceHandlerUtil.getType(errorMessage,UNPROCESSABLE_ENTITY_SPEC));
    msg.setTitle(ResourceHandlerUtil.getTitle(errorMessage,HttpStatus.UNPROCESSABLE_ENTITY));
    msg.setDetail(ResourceHandlerUtil.getDetail(errorMessage,HttpStatus.UNPROCESSABLE_ENTITY));
    msg.setInstance(ResourceHandlerUtil.getUriInstance(errorMessage,UNPROCESSABLE_ENTITY_URI));
    LOGGER.debug("ResourceBusinessExceptionHandler - Complete");
    return msg;
}

我的配置bean：

<bean id="compositeExceptionResolver" class="org.springframework.web.servlet.handler.HandlerExceptionResolverComposite">
    <property name="order" value="0" />
    <property name="exceptionResolvers">
        <list>
            <ref bean="exceptionHandlerExceptionResolver" />
            <ref bean="restExceptionResolver" />
        </list>
    </property>
</bean>

    <bean id="restExceptionResolver" class="cz.jirutka.spring.exhandler.RestHandlerExceptionResolverFactoryBean">
    <property name="messageSource" ref="httpErrorMessageSource" />
    <property name="defaultContentType" value="application/json" />
    <property name="exceptionHandlers">
        <map>
            <!-- 422 -->
            <entry key="com.company.project.exception.ResourceBusinessException">
                <bean class="com.company.project.exception.handler.ResourceBusinessExceptionHandler"/>
            </entry>
        </map>
    </property>
</bean><bean id="exceptionHandlerExceptionResolver" class="org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver"/>

<bean id="httpErrorMessageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource" p:defaultEncoding="UTF-8"/>

  protected void processResponse(ResponseEntity<?> entity, NativeWebRequest webRequest) throws Exception {

    ModelAndViewContainer mavContainer = new ModelAndViewContainer();
    try {
        responseProcessor.handleReturnValue(entity, null, mavContainer, webRequest);

    } catch (HttpMediaTypeNotAcceptableException ex) {
        LOG.debug("Requested media type is not supported, falling back to default one");
        fallbackResponseProcessor.handleReturnValue(entity, null, mavContainer, webRequest);
    }
}

Answer 1

我发现了问题所在。我使用的Spring版本与Spring-rest-exception-handler-version不兼容。我使用的rest异常处理程序来自这个github项目：https://github.com/jirutka/spring-rest-exception-handler。

因此，如果您使用的是Spring4.2.6发行版，那么应该将spring-rest-exception-handler的版本更新到1.2.0。这应该可以解决NullPointerException。