春季：FasterXML無法使用修飾符private訪問類的成員

Question

我從某個地方收到一個未知的錯誤，這一切都從今天開始。 我不知道出了什么問題。 我找不到很多有此問題的帖子。 我正在發布錯誤日志和配置。 誰能告訴我哪里出了問題。 謝謝。

錯誤日志：

Sep 08, 2015 2:21:47 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [appServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.IllegalStateException: Failed to instantiate standard serializer (of type com.fasterxml.jackson.databind.ser.std.NullSerializer): Class com.fasterxml.jackson.databind.ser.BasicSerializerFactory can not access a member of class com.fasterxml.jackson.databind.ser.std.NullSerializer with modifiers "private"] with root cause
java.lang.IllegalAccessException: Class com.fasterxml.jackson.databind.ser.BasicSerializerFactory can not access a member of class com.fasterxml.jackson.databind.ser.std.NullSerializer with modifiers "private"
    at sun.reflect.Reflection.ensureMemberAccess(Reflection.java:102)
    at java.lang.Class.newInstance(Class.java:436)
    at com.fasterxml.jackson.databind.ser.BasicSerializerFactory.findSerializerByLookup(BasicSerializerFactory.java:299)
    at com.fasterxml.jackson.databind.ser.BeanSerializerFactory._createSerializer2(BeanSerializerFactory.java:210)
    at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.createSerializer(BeanSerializerFactory.java:152)
    at com.fasterxml.jackson.databind.SerializerProvider._createUntypedSerializer(SerializerProvider.java:1077)
    at com.fasterxml.jackson.databind.SerializerProvider._createAndCacheUntypedSerializer(SerializerProvider.java:1037)
    at com.fasterxml.jackson.databind.SerializerProvider._findExplicitUntypedSerializer(SerializerProvider.java:1018)
    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.hasSerializerFor(DefaultSerializerProvider.java:336)
    at com.fasterxml.jackson.databind.ObjectMapper.canSerialize(ObjectMapper.java:1996)
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.canWrite(AbstractJackson2HttpMessageConverter.java:162)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.getProducibleMediaTypes(AbstractMessageConverterMethodProcessor.java:204)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:122)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:101)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:167)
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:71)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:126)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.filters.ExpiresFilter.doFilter(ExpiresFilter.java:1179)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:316)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:126)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:122)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:157)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:168)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:48)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:205)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:120)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:53)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.session.ConcurrentSessionFilter.doFilter(ConcurrentSessionFilter.java:133)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:91)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:213)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:176)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

配置文件：

root-context.xml：

    <context:component-scan base-package="com.journaldev.spring">
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

    <context:property-placeholder location="classpath:application.properties"/>

    <beans:bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
                destroy-method="close">
        <beans:property name="driverClassName" value="org.postgresql.Driver"/>
        <beans:property name="url"
                        value="jdbc:postgresql://localhost:5432/Person2"/>
        <beans:property name="username" value="username"/>
        <beans:property name="password" value="password"/>
        <beans:property name="removeAbandoned" value="true"/>
        <beans:property name="removeAbandonedTimeout" value="20"/>
        <beans:property name="defaultAutoCommit" value="false"/>
    </beans:bean>

    <!-- Hibernate 4 SessionFactory Bean definition -->
    <beans:bean id="hibernate4AnnotatedSessionFactory"
                class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <beans:property name="dataSource" ref="dataSource"/>
        <beans:property name="packagesToScan" value="com.journaldev.spring.model"/>

        <beans:property name="hibernateProperties">
            <beans:props>
                <beans:prop key="hibernate.dialect">org.hibernate.dialect.PostgreSQL9Dialect</beans:prop>
                <beans:prop key="hibernate.show_sql">false</beans:prop>
                <!--   <beans:prop key="hibernate.jdbc.batch_size">1000</beans:prop>
                   <beans:prop key="hibernate.order_updates">true</beans:prop>-->
                <beans:prop key="hibernate.hbm2ddl.auto">update</beans:prop>
                <beans:prop key="cache.use_second_level_cache">true</beans:prop>
                <beans:prop key="cache.use_query_cache">true</beans:prop>
            </beans:props>
        </beans:property>
    </beans:bean>

    <beans:bean id="LoginServiceImpl" class="com.journaldev.spring.service.LoginServiceImpl"/>

    <task:annotation-driven/>

    <tx:annotation-driven transaction-manager="transactionManager"/>

    <beans:bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <beans:property name="sessionFactory" ref="hibernate4AnnotatedSessionFactory"/>
    </beans:bean>

    <cache:annotation-driven />

    <beans:bean id="cacheManager" class="org.springframework.cache.support.SimpleCacheManager">
        <beans:property name="caches">
            <beans:set>
                <beans:bean class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean"
                        p:name="person"/>
           </beans:set>
        </beans:property>
    </beans:bean>

    <!-- Configuration for Spring-Data-Redis -->
    <beans:bean id="jedisConnFactory"
                class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory" p:usePool="true"/>

    <beans:bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate" p:connectionFactory-ref="jedisConnFactory"/>

</beans:beans>

Servlet-context.xml：

  <security:global-method-security
            secured-annotations="enabled"
            jsr250-annotations="disabled"
            pre-post-annotations="enabled"/>

    <context:component-scan base-package="com.journaldev.spring" use-default-filters="false">
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

    <context:property-placeholder location="classpath:application.properties"/>

    <mvc:annotation-driven>
        <mvc:argument-resolvers>
            <beans:bean class="org.springframework.mobile.device.DeviceWebArgumentResolver"/>
        </mvc:argument-resolvers>
    </mvc:annotation-driven>
    <mvc:interceptors>
        <beans:bean class="org.springframework.mobile.device.DeviceResolverHandlerInterceptor"/>
        <beans:ref bean="localeChangeInterceptor"/>
    </mvc:interceptors>

    <mvc:default-servlet-handler/>

    <resources mapping="/resources/" location="/resources/"/>

    <beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <beans:property name="prefix" value="/WEB-INF/views/"/>
        <beans:property name="suffix" value=".jsp"/>
    </beans:bean>

    <!-- locale -->
    <beans:bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
        <beans:property name="basename" value="classpath:/locale/messages"/>
        <beans:property name="defaultEncoding" value="UTF-8"/>
    </beans:bean>


    <!-- default locale -->
    <beans:bean id="localeResolver" class="org.springframework.web.servlet.i18n.SessionLocaleResolver">
        <beans:property name="defaultLocale" value="de"/>
    </beans:bean>

    <!-- Change locale via url. -->
    <beans:bean id="localeChangeInterceptor" class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
        <beans:property name="paramName" value="lang"/>
    </beans:bean>

    <beans:bean id="handlerMapping"
                class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping">
        <beans:property name="interceptors">
            <beans:list>
                <beans:ref bean="localeChangeInterceptor"/>
            </beans:list>
        </beans:property>
    </beans:bean>

    <beans:bean class="com.journaldev.spring.service.DoNotTruncateMyUrls"/>

    <beans:bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <beans:property name="maxUploadSize" value="2147483648"/>
    </beans:bean>
    <!--  52428800 -->


</beans:beans>

POM.xml：

由於正文限制而無法放入POM.xml， 這是pastebin的URL

如果還有其他必要，請告訴我。

樹：

[INFO] TOOLTANK:TOOLTANK:war:2.0-SNAPSHOT
[INFO] +- com.evernote:evernote-api:jar:1.25.1:compile
[INFO] +- org.scribe:scribe:jar:1.3.7:compile
[INFO] +- com.memetix:microsoft-translator-java-api:jar:0.6.2:compile
[INFO] +- com.atlassian.jira:jira-components:pom:6.4.9:compile
[INFO] +- org.apache.httpcomponents:httpclient:jar:4.5:compile
[INFO] |  \- org.apache.httpcomponents:httpcore:jar:4.4.1:compile
[INFO] +- com.atlassian.jira:jira-rest-java-client-core:jar:2.0.0-m26:compile
[INFO] |  +- com.atlassian.jira:jira-rest-java-client-api:jar:2.0.0-m26:compile
[INFO] |  |  \- com.atlassian.httpclient:atlassian-httpclient-api:jar:0.13.2:compile
[INFO] |  |     \- com.atlassian.httpclient:atlassian-httpclient-spi:jar:0.13.2:compile
[INFO] |  +- com.atlassian.httpclient:atlassian-httpclient-apache-httpcomponents:jar:0.13.2:compile
[INFO] |  |  +- com.atlassian.sal:sal-api:jar:2.7.0:compile
[INFO] |  |  +- com.atlassian.event:atlassian-event:jar:2.2.0:compile
[INFO] |  |  +- org.apache.httpcomponents:httpasyncclient-cache:jar:4.0-beta3-atlassian-1:compile
[INFO] |  |  +- org.apache.httpcomponents:httpclient-cache:jar:4.2.1-atlassian-2:compile
[INFO] |  |  +- org.apache.httpcomponents:httpasyncclient:jar:4.0-beta3-atlassian-1:compile
[INFO] |  |  \- org.apache.httpcomponents:httpcore-nio:jar:4.2.2:compile
[INFO] |  +- com.atlassian.util.concurrent:atlassian-util-concurrent:jar:2.4.0-M9:compile
[INFO] |  +- org.apache.httpcomponents:httpmime:jar:4.1.2:compile
[INFO] |  \- com.google.guava:guava:jar:10.0.1:compile
[INFO] +- com.sun.jersey:jersey-client:jar:1.8-atlassian-11:compile
[INFO] +- com.sun.jersey:jersey-json:jar:1.8-atlassian-11:compile
[INFO] |  +- org.codehaus.jettison:jettison:jar:1.1:compile
[INFO] |  |  \- stax:stax-api:jar:1.0.1:compile
[INFO] |  +- com.sun.xml.bind:jaxb-impl:jar:2.2.3-1:compile
[INFO] |  |  \- javax.xml.bind:jaxb-api:jar:2.2.2:compile
[INFO] |  |     \- javax.xml.stream:stax-api:jar:1.0-2:compile
[INFO] |  +- org.codehaus.jackson:jackson-core-asl:jar:1.7.1:compile
[INFO] |  +- org.codehaus.jackson:jackson-mapper-asl:jar:1.7.1:compile
[INFO] |  +- org.codehaus.jackson:jackson-jaxrs:jar:1.7.1:compile
[INFO] |  \- org.codehaus.jackson:jackson-xc:jar:1.7.1:compile
[INFO] +- com.sun.jersey:jersey-core:jar:1.8-atlassian-11:compile
[INFO] +- com.googlecode.json-simple:json-simple:jar:1.1.1:compile
[INFO] |  \- junit:junit:jar:4.10:compile
[INFO] |     \- org.hamcrest:hamcrest-core:jar:1.1:compile
[INFO] +- com.atlassian.jira:jira-rest-java-client:jar:0.2:compile
[INFO] |  +- com.sun.jersey.contribs:jersey-multipart:jar:1.5:compile
[INFO] |  |  \- org.jvnet:mimepull:jar:1.4:compile
[INFO] |  +- com.sun.jersey.contribs:jersey-apache-client:jar:1.5:compile
[INFO] |  |  \- commons-httpclient:commons-httpclient:jar:3.1:compile
[INFO] |  +- com.sun.jersey.contribs.jersey-oauth:oauth-client:jar:1.5:compile
[INFO] |  \- com.sun.jersey.contribs.jersey-oauth:oauth-signature:jar:1.5:compile
[INFO] +- org.mnode.ical4j:ical4j:jar:1.0.6:compile
[INFO] |  +- commons-lang:commons-lang:jar:2.6:compile
[INFO] |  \- backport-util-concurrent:backport-util-concurrent:jar:3.1:compile
[INFO] +- org.springframework.data:spring-data-redis:jar:1.5.2.RELEASE:compile
[INFO] |  +- org.springframework:spring-context:jar:4.0.9.RELEASE:compile
[INFO] |  +- org.springframework:spring-context-support:jar:4.0.9.RELEASE:compile
[INFO] |  \- org.springframework:spring-aop:jar:4.0.9.RELEASE:compile
[INFO] +- redis.clients:jedis:jar:2.7.3:compile
[INFO] +- org.springframework.data:spring-data-commons:jar:1.10.2.RELEASE:compile
[INFO] +- org.apache.commons:commons-pool2:jar:2.4.2:compile
[INFO] +- com.google.apis:google-api-services-drive:jar:v2-rev175-1.18.0-rc:compile
[INFO] +- com.google.apis:google-api-services-oauth2:jar:v2-rev92-1.20.0:compile
[INFO] +- com.dropbox.core:dropbox-core-sdk:jar:1.7.7:compile
[INFO] +- org.hibernate:hibernate-search-orm:jar:5.2.0.Final:compile
[INFO] |  \- org.hibernate:hibernate-search-engine:jar:5.2.0.Final:compile
[INFO] |     +- org.apache.lucene:lucene-core:jar:4.10.4:compile
[INFO] |     +- org.apache.lucene:lucene-analyzers-common:jar:4.10.4:compile
[INFO] |     \- org.apache.lucene:lucene-facet:jar:4.10.4:compile
[INFO] |        \- org.apache.lucene:lucene-queries:jar:4.10.4:compile
[INFO] +- org.springframework.mobile:spring-mobile-device:jar:1.1.3.RELEASE:compile
[INFO] +- org.springframework:spring-beans:jar:4.1.6.RELEASE:compile
[INFO] +- org.springframework:spring-web:jar:4.1.6.RELEASE:compile
[INFO] +- com.google.apis:google-api-services-calendar:jar:v3-rev121-1.19.0:compile
[INFO] +- com.google.http-client:google-http-client-jackson:jar:1.19.0:compile
[INFO] +- org.springframework.security.oauth:spring-security-oauth2:jar:2.0.3.RELEASE:compile
[INFO] +- com.google.oauth-client:google-oauth-client-jetty:jar:1.19.0:compile
[INFO] |  +- com.google.oauth-client:google-oauth-client-java6:jar:1.19.0:compile
[INFO] |  \- org.mortbay.jetty:jetty:jar:6.1.26:compile
[INFO] |     +- org.mortbay.jetty:jetty-util:jar:6.1.26:compile
[INFO] |     \- org.mortbay.jetty:servlet-api:jar:2.5-20081211:compile
[INFO] +- org.cometd.java:bayeux-api:jar:3.0.4:compile
[INFO] +- org.cometd.javascript:cometd-javascript-jquery:war:3.0.4:compile
[INFO] +- org.cometd.java:cometd-java-server:jar:3.0.4:compile
[INFO] |  +- org.cometd.java:cometd-java-common:jar:3.0.4:compile
[INFO] |  |  \- org.eclipse.jetty:jetty-util-ajax:jar:9.2.9.v20150224:compile
[INFO] |  +- org.eclipse.jetty:jetty-util:jar:9.2.9.v20150224:compile
[INFO] |  \- org.eclipse.jetty:jetty-jmx:jar:9.2.9.v20150224:compile
[INFO] +- org.eclipse.jetty:jetty-client:jar:9.2.9.v20150224:compile
[INFO] |  +- org.eclipse.jetty:jetty-http:jar:9.2.9.v20150224:compile
[INFO] |  \- org.eclipse.jetty:jetty-io:jar:9.2.9.v20150224:compile
[INFO] +- org.cometd.java:cometd-java-client:jar:3.0.4:compile
[INFO] +- org.cometd.java:cometd-java-annotations:jar:3.0.4:compile
[INFO] |  \- javax.annotation:jsr250-api:jar:1.0:compile
[INFO] +- org.eclipse.jetty:jetty-servlets:jar:9.2.9.v20150224:compile
[INFO] |  \- org.eclipse.jetty:jetty-continuation:jar:9.2.9.v20150224:compile
[INFO] +- com.google.apis:google-api-services-plus:jar:v1-rev216-1.20.0:compile
[INFO] +- org.imgscalr:imgscalr-lib:jar:4.2:compile
[INFO] +- com.google.api-client:google-api-client:jar:1.19.1:compile
[INFO] |  +- com.google.oauth-client:google-oauth-client:jar:1.19.0:compile
[INFO] |  +- com.google.http-client:google-http-client-jackson2:jar:1.19.0:compile
[INFO] |  \- com.google.guava:guava-jdk5:jar:13.0:compile
[INFO] +- com.google.http-client:google-http-client:jar:1.19.0:compile
[INFO] |  \- com.google.code.findbugs:jsr305:jar:1.3.9:compile
[INFO] +- xml-apis:xml-apis:jar:1.4.01:compile
[INFO] +- commons-io:commons-io:jar:1.3.2:compile
[INFO] +- commons-fileupload:commons-fileupload:jar:1.3.1:compile
[INFO] +- javax.validation:validation-api:jar:1.0.0.GA:compile
[INFO] +- org.hibernate:hibernate-validator:jar:4.3.1.Final:compile
[INFO] |  \- org.jboss.logging:jboss-logging:jar:3.1.0.CR2:compile
[INFO] +- org.springframework:spring-webmvc:jar:4.1.6.RELEASE:compile
[INFO] |  \- org.springframework:spring-expression:jar:4.1.6.RELEASE:compile
[INFO] +- org.springframework:spring-tx:jar:4.1.6.RELEASE:compile
[INFO] +- org.springframework:spring-core:jar:4.1.6.RELEASE:compile
[INFO] +- org.springframework:spring-orm:jar:4.1.6.RELEASE:compile
[INFO] |  \- org.springframework:spring-jdbc:jar:4.1.6.RELEASE:compile
[INFO] +- org.hibernate:hibernate-core:jar:4.3.9.Final:compile
[INFO] |  +- org.jboss.logging:jboss-logging-annotations:jar:1.2.0.Beta1:compile
[INFO] |  +- org.jboss.spec.javax.transaction:jboss-transaction-api_1.2_spec:jar:1.0.0.Final:compile
[INFO] |  +- dom4j:dom4j:jar:1.6.1:compile
[INFO] |  +- org.hibernate.common:hibernate-commons-annotations:jar:4.0.5.Final:compile
[INFO] |  +- org.hibernate.javax.persistence:hibernate-jpa-2.1-api:jar:1.0.0.Final:compile
[INFO] |  +- org.javassist:javassist:jar:3.18.1-GA:compile
[INFO] |  +- antlr:antlr:jar:2.7.7:compile
[INFO] |  \- org.jboss:jandex:jar:1.1.0.Final:compile
[INFO] +- org.hibernate:hibernate-entitymanager:jar:4.3.9.Final:compile
[INFO] +- commons-dbcp:commons-dbcp:jar:1.4:compile
[INFO] |  \- commons-pool:commons-pool:jar:1.5.4:compile
[INFO] +- org.aspectj:aspectjrt:jar:1.7.4:compile
[INFO] +- joda-time:joda-time:jar:2.3:compile
[INFO] +- com.itextpdf:itextpdf:jar:5.0.6:compile
[INFO] |  +- org.bouncycastle:bcmail-jdk14:jar:1.38:compile
[INFO] |  +- org.bouncycastle:bcprov-jdk14:jar:1.38:compile
[INFO] |  \- org.bouncycastle:bctsp-jdk14:jar:1.38:compile
[INFO] +- commons-codec:commons-codec:jar:1.9:compile
[INFO] +- javax.mail:mail:jar:1.4.4:compile
[INFO] |  \- javax.activation:activation:jar:1.1:compile
[INFO] +- org.slf4j:slf4j-api:jar:1.7.5:compile
[INFO] +- org.slf4j:jcl-over-slf4j:jar:1.7.5:runtime
[INFO] +- org.slf4j:slf4j-log4j12:jar:1.7.5:runtime
[INFO] +- log4j:log4j:jar:1.2.15:runtime
[INFO] +- javax.inject:javax.inject:jar:1:compile
[INFO] +- javax.servlet:javax.servlet-api:jar:3.1.0:provided
[INFO] +- javax.servlet.jsp:jsp-api:jar:2.1:provided
[INFO] +- javax.servlet:jstl:jar:1.2:compile
[INFO] +- com.fasterxml.jackson.core:jackson-core:jar:2.3.3:compile
[INFO] +- com.fasterxml.jackson.core:jackson-databind:jar:2.3.3:compile
[INFO] |  \- com.fasterxml.jackson.core:jackson-annotations:jar:2.3.0:compile
[INFO] +- org.springframework.security:spring-security-web:jar:4.0.1.RELEASE:compile
[INFO] |  \- aopalliance:aopalliance:jar:1.0:compile
[INFO] +- org.springframework.security:spring-security-config:jar:4.0.1.RELEASE:compile
[INFO] +- org.springframework.security:spring-security-taglibs:jar:4.0.1.RELEASE:compile
[INFO] |  \- org.springframework.security:spring-security-acl:jar:4.0.1.RELEASE:compile
[INFO] +- org.springframework.security:spring-security-core:jar:4.0.1.RELEASE:compile
[INFO] +- commons-logging:commons-logging:jar:1.2:compile
[INFO] +- org.postgresql:postgresql:jar:9.3-1102-jdbc41:compile
[INFO] +- xerces:xercesImpl:jar:2.11.0:compile
[INFO] +- com.google.code.gson:gson:jar:2.3.1:compile
[INFO] \- org.json:json:jar:20141113:compile
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 11.406s
[INFO] Finished at: Tue Sep 08 14:36:02 CEST 2015
[INFO] Final Memory: 23M/404M

Answer 1

參見https://github.com/FasterXML/jackson-databind/issues/851

在Jackson 2 2.4.0之前的版本中，這似乎是一個問題。 將Jackson 1也放在類路徑上似乎並不理想，但應該無關緊要，因為它們占用了完全不同的包名稱空間。

Answer 2

當我從Spring MVC控制器方法返回void時，出現此錯誤。 返回一個空的String修復了它。 工作方法如下所示：

@RequestMapping(value="/deleteWidget", method=RequestMethod.POST)
@ResponseBody
public String deleteWidget(HttpServletRequest request) {
    widgetService.deleteWidget(request.getParameter("widgetId"));
    return "";
}

Answer 3

您調用的函數應具有返回值（字符串或null等）。 該功能不應為空。