解决Jackson报错：can not access a member of class xx.xx.ser.std.NullSerializer with modifiers "private"

﹏ヽ暗。殇╰゛Y 2022-05-13 11:06 322阅读 0赞

##                     解决 Jackson 报错：can not access a member of class com.fasterxml.jackson.databind.ser.std.NullSerializer with modifiers "private" ##

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一、问题描述

1、在使用 ssm 框架，返回 json 数据时候，**第一次会抛出一个异常**： " **can not access a member of class ... NullSerializer with modifiers "private"** "，再刷新一次，就好了，正常返回json数据，对项目使用，影响不大。

2、异常信息如下：

2018-09-12 11:32:12,532 ERROR [500.jsp] - Could not write JSON: 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" (through reference chain: java.util.ArrayList[0]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: 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" (through reference chain: java.util.ArrayList[0])
    org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: 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" (through reference chain: java.util.ArrayList[0]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: 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" (through reference chain: java.util.ArrayList[0])
    at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.writeInternal(MappingJackson2HttpMessageConverter.java:256)
    at org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:208)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:143)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:89)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:188)
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:71)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:689)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
    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 com.opensymphony.sitemesh.webapp.SiteMeshFilter.obtainContent(SiteMeshFilter.java:129)
    at com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:77)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
    at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
    at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
    at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
    at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
    at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
    at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
    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.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:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
    
    Caused by: com.fasterxml.jackson.databind.JsonMappingException: 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" (through reference chain: java.util.ArrayList[0])
    at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:232)
    at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:211)
    at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:210)
    at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:105)
    at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:21)
    at com.fasterxml.jackson.databind.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:186)
    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118)
    at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:1819)
    at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.writeInternal(MappingJackson2HttpMessageConverter.java:253)
    ... 55 more
    
    Caused by: 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"
    at com.fasterxml.jackson.databind.ser.BasicSerializerFactory.findSerializerByLookup(BasicSerializerFactory.java:303)
    at com.fasterxml.jackson.databind.ser.BeanSerializerFactory._createSerializer2(BeanSerializerFactory.java:210)
    ... 此处省略 n 行 ...

3、后台返回 json 数据代码：

@RequestMapping(value={"/getJson"})
    @ResponseBody
    public List<User> getJson(User user){
        List<User> list = userService.getUserList(user);
        return list;
    }

二、项目基本信息

1、ssm 架构，spring 4.x.x

2、server Tomcat7

3、jackson-xx-2.2.3.jar （jackson 相关jar包版本 2.2.3 ）

三、问题解决

1、 升级 jackson 相关jar包，**到 2.4.6 或以上**，即可解决问题。

2、 已经验证jackson相关 jar包，升级到2.5.0，不再出现 （一 - 1）中描述的异常信息，问题解决。 jackson-annotations-2.5.0.jar ， jackson-core-2.5.0.jar，jackson-databind-2.5.0.jar 即可。

3、解决办法引用这里： [https://github.com/FasterXML/jackson-databind/issues/851][https_github.com_FasterXML_jackson-databind_issues_851]

4、若您不会下载jar包，点击 [这里][Link 1] 。

参考资料：

[https://stackoverflow.com/questions/32457895/spring-fasterxml-cannot-access-a-member-of-class-with-modifiers-private][https_stackoverflow.com_questions_32457895_spring-fasterxml-cannot-access-a-member-of-class-with-modifiers-private]

[http://www.itkeyword.com/doc/9081122533937053x454/spring-fasterxml-cannot-access-a-member-of-class-with-modifiers-private][http_www.itkeyword.com_doc_9081122533937053x454_spring-fasterxml-cannot-access-a-member-of-class-with-modifiers-private]

[https_github.com_FasterXML_jackson-databind_issues_851]: https://github.com/FasterXML/jackson-databind/issues/851
[Link 1]: https://download.csdn.net/download/haha_sir/10661969
[https_stackoverflow.com_questions_32457895_spring-fasterxml-cannot-access-a-member-of-class-with-modifiers-private]: https://stackoverflow.com/questions/32457895/spring-fasterxml-cannot-access-a-member-of-class-with-modifiers-private
[http_www.itkeyword.com_doc_9081122533937053x454_spring-fasterxml-cannot-access-a-member-of-class-with-modifiers-private]: http://www.itkeyword.com/doc/9081122533937053x454/spring-fasterxml-cannot-access-a-member-of-class-with-modifiers-private