Spring REST：HttpMediaTypeNotSupportedException：內容類型'application / json; charset = UTF-8'

Question

由於傑克遜試圖反序列化我的POJO，我收到了上述錯誤。

我調試了代碼，它在Jackson的ObjectMapper中返回false：

public boolean canRead(Type type, Class<?> contextClass, MediaType mediaType) {
    JavaType javaType = getJavaType(type, contextClass);
    return (this.objectMapper.canDeserialize(javaType) && canRead(mediaType));
}

this.objectMapper.canDeserialize（javaType）返回false，導致錯誤

我的控制器如下：

@Controller
public class CancelController {
    @Autowired
    private CancelService cancelService;

    @RequestMapping( value="/thing/cancel", method=RequestMethod.POST, consumes="application/json" )
    public @ResponseBody CancelThingResponseDTO cancelThing(@RequestBody CancelRequestDTO cancelThingRequest) {
        return cancelService.cancelThing(cancelThingRequest);
    }

我的CancelRequestDTO實現了Serializable：

public class CancelRequestDTO implements Serializable{
  /**
   * Default serialization ID
   */
  private static final long serialVersionUID = 1L;
  /**
   * Reason code associated with the request
   */
  private final String reasonCode;
  /**
   * Identifier of the entity associated with the request
   */
  private final EntityIdentifier entityIdentifier;

  /**
   * Default constructor
   *
   * @param reasonCode Reason code associated with the request
   * @param entityIdentifier Identifier of the entity associated with the request
   */
  public CancelRequestDTO(String reasonCode, EntityIdentifier entityIdentifier) {
    super();
    this.reasonCode = reasonCode;
    this.entityIdentifier = entityIdentifier;
  }
  /**
   * @return Returns the reasonCode.
   */
  public String getReasonCode() {
    return reasonCode;
  }
  /**
   * @return Returns the entityIdentifier.
   */
  public EntityIdentifier getEntityIdentifier() {
    return entityIdentifier;
  }
}

我的Spring配置如下：

<!-- DispatcherServlet Context: defines this servlet's request-processing
    infrastructure -->

<!-- Enables the Spring MVC @Controller programming model -->
<mvc:annotation-driven />

<!-- Scan for stereotype annotations -->
<context:component-scan base-package="com.cancel.web.controller" />

<bean id="viewNameTranslator"
    class="org.springframework.web.servlet.view.DefaultRequestToViewNameTranslator" />

<bean class="org.springframework.web.servlet.view.BeanNameViewResolver" />





<bean id="jsonView"
    class="org.springframework.web.servlet.view.json.MappingJacksonJsonView" >
    <property name="contentType" value="application/json;charset=UTF-8"/>
    </bean>

<!-- Register JSON Converter for RESTful Web Service -->
<bean
    class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="messageConverters">
        <list>
            <bean
                class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
            </bean>
        </list>
    </property>
</bean>

有誰知道這可能導致這個反序列化問題？

謝謝

Answer 1

我的DTO沒有帶有setter的默認構造函數！ 所以看起來像傑克遜的一個不准確的例外

Answer 2

對於仍然面臨這個問題的人，你不能在一個類中有兩個@JsonBackReference ，像這樣添加一個引用@JsonBackReference(value = "secondParent")也將相同的值添加到@JsonManagedReference(value ="secondParent")在父類中。

Answer 3

我總是使用ContentNegotiatingViewResolver完成此操作。 它似乎無法理解您傳遞的內容類型。 這是我通常用於執行您嘗試執行的操作的配置：

<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
    <property name="order" value="1" />
    <property name="contentNegotiationManager">
        <bean class="org.springframework.web.accept.ContentNegotiationManager">
            <constructor-arg>
                <bean class="org.springframework.web.accept.PathExtensionContentNegotiationStrategy">
                    <constructor-arg>
                        <map>
                            <entry key="json" value="application/json" />
                            <entry key="xml" value="application/xml" />
                        </map>
                    </constructor-arg>
                </bean>
            </constructor-arg>
        </bean>
    </property>

    <property name="defaultViews">
        <list>
            <bean class="org.springframework.web.servlet.view.json.MappingJacksonJsonView" />
            <bean class="org.springframework.web.servlet.view.xml.MarshallingView">
                <constructor-arg>
                    <bean class="org.springframework.oxm.xstream.XStreamMarshaller">
                        <property name="autodetectAnnotations" value="true" />
                    </bean>
                </constructor-arg>
            </bean>
        </list>
    </property>
</bean>

這個視頻完成了你正在嘗試通過UI中的jQuery消費服務所做的事情：

http://pluralsight.com/training/Courses/TableOfContents/springmvc-intro