Spring - Jackson 请求映射与验证。当为 long 属性给出字符串时抛出 "HttpMessageNotReadableException"

Question

我正在尝试使用@RequestBody @Valid 注释在 Spring 中进行 bean 验证和数据映射。

正如您在实体 bean 中看到的那样，我使用了 @NotNull 和 @Min 注释，它们都使用了不同的验证消息，我可以在 BindingResult 参数的 Controller 中读取这些消息。

但是，当客户端为“operatorId”字段发送 String 值而不是 long 时，我收到一个错误，您可以在下面看到它。

我的问题是:

当客户端为 operatorId 设置一个非数字字符串值时，我想向客户端返回一条错误消息文本。 (例如:“您应该发送一个数值等”)

实体 Bean:

@Entity(name="ua")
@Table(name="ua")
public class UserAgreement extends BaseContractEntity {

    @Column(name = "OPERATOR_ID")
    @NotNull(message = "operatorId must be provided")
    @Min(value = 1, message = "operatorId must be bigger then zero")
    protected long operatorId;


    //... getters setters, etc
}

Controller :

@RequestMapping(value = "/ug", method = RequestMethod.POST)
@ResponseBody
public ServiceResponse saveUserAgreement(@RequestBody @Valid UserAgreement userAgreement,
                                     BindingResult result) {

    ServiceResponse serviceResponse = new ServiceResponse();

    if(result.hasErrors()) {

        serviceResponse.setMessage(result.getAllErrors().get(0).getDefaultMessage());
        serviceResponse.setErrorCode("400");
        return serviceResponse;

    } else {

        // call service
        serviceResponse.setMessage("ok");
        return serviceResponse;
    }
}

这是我的示例请求:

当使用此 json 文本发出 POST 请求时(错误的 operatorId 非数字值!):

{"content":"text content text","announcement":"YES","approved":"YES","operatorId":"5fg0"}

出现这个错误:

    org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Can not construct instance of long from String value '5fg0': not a valid Long value
 at [Source: org.apache.catalina.connector.CoyoteInputStream@9ba3afe; line: 1, column: 69] (through reference chain: com.ggg.agr.core.model.UserAgreement["operatorId"]); nested exception is org.codehaus.jackson.map.JsonMappingException: Can not construct instance of long from String value '5fg0': not a valid Long value
 at [Source: org.apache.catalina.connector.CoyoteInputStream@9ba3afe; line: 1, column: 69] (through reference chain: com.ggg.agr.core.model.UserAgreement["operatorId"])
    at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.readJavaType(MappingJacksonHttpMessageConverter.java:169)
    at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.read(MappingJacksonHttpMessageConverter.java:161)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:135)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:180)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:95)
    at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:77)
    at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:162)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:123)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:838)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
    at java.lang.Thread.run(Thread.java:680)
Caused by: org.codehaus.jackson.map.JsonMappingException: Can not construct instance of long from String value '5fg0': not a valid Long value
 at [Source: org.apache.catalina.connector.CoyoteInputStream@9ba3afe; line: 1, column: 69] (through reference chain: com.ggg.agr.core.model.UserAgreement["operatorId"])
    at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:163)
    at org.codehaus.jackson.map.deser.StdDeserializationContext.weirdStringException(StdDeserializationContext.java:243)
    at org.codehaus.jackson.map.deser.std.StdDeserializer._parseLong(StdDeserializer.java:351)
    at org.codehaus.jackson.map.deser.std.StdDeserializer$LongDeserializer.deserialize(StdDeserializer.java:846)
    at org.codehaus.jackson.map.deser.std.StdDeserializer$LongDeserializer.deserialize(StdDeserializer.java:833)
    at org.codehaus.jackson.map.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:299)
    at org.codehaus.jackson.map.deser.SettableBeanProperty$MethodProperty.deserializeAndSet(SettableBeanProperty.java:414)
    at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:697)
    at org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:580)
    at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2732)
    at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1923)
    at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.readJavaType(MappingJacksonHttpMessageConverter.java:166)
    ... 38 more

Answer 1

重要的是要了解，首先 Jackson 反序列化请求正文的 JSON 内容并创建一个 UserAgreement 对象。只有这样才能应用标准 bean 验证作为 @Valid 注释的结果。所以你可以把@Valid看做是JSON反序列化成功后才加的一层验证。对反序列化错误使用 @ExceptionHandler 方法。