以下是错误信息：

Caused by: java.lang.IllegalStateException: circular reference error
  Offending field: methodAccessor

  Offending object: preserveType: false, type: interface sun.reflect.MethodAccessor, obj: sun.reflect.DelegatingMethodAccessorImpl@5886f7bf
    at com.google.gson.CircularReferenceException.createDetailedException(CircularReferenceException.java:43)
    at com.google.gson.JsonSerializationVisitor.visitObjectField(JsonSerializationVisitor.java:115)
    at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:164)
    at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:131)
    at com.google.gson.JsonSerializationVisitor.getJsonElementForChild(JsonSerializationVisitor.java:147)
    at com.google.gson.JsonSerializationVisitor.addAsChildOfObject(JsonSerializationVisitor.java:125)
    at com.google.gson.JsonSerializationVisitor.visitObjectField(JsonSerializationVisitor.java:112)
    at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:164)
    at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:131)
    at com.google.gson.JsonSerializationVisitor.getJsonElementForChild(JsonSerializationVisitor.java:147)
    at com.google.gson.JsonSerializationVisitor.addAsChildOfObject(JsonSerializationVisitor.java:125)
    at com.google.gson.JsonSerializationVisitor.visitObjectField(JsonSerializationVisitor.java:112)
    at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:164)
    at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:131)
    at com.google.gson.JsonSerializationVisitor.getJsonElementForChild(JsonSerializationVisitor.java:147)
    at com.google.gson.JsonSerializationVisitor.addAsChildOfObject(JsonSerializationVisitor.java:125)
    at com.google.gson.JsonSerializationVisitor.visitObjectField(JsonSerializationVisitor.java:112)
    at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:164)
    at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:131)
    at com.google.gson.JsonSerializationVisitor.getJsonElementForChild(JsonSerializationVisitor.java:147)
    at com.google.gson.JsonSerializationVisitor.addAsChildOfObject(JsonSerializationVisitor.java:125)
    at com.google.gson.JsonSerializationVisitor.visitObjectField(JsonSerializationVisitor.java:112)
    at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:164)
    at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:131)
    at com.google.gson.JsonSerializationVisitor.getJsonElementForChild(JsonSerializationVisitor.java:147)
    at com.google.gson.JsonSerializationVisitor.addAsChildOfObject(JsonSerializationVisitor.java:125)
    at com.google.gson.JsonSerializationVisitor.visitObjectField(JsonSerializationVisitor.java:112)
    at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:164)
    at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:131)
    at com.google.gson.JsonSerializationVisitor.getJsonElementForChild(JsonSerializationVisitor.java:147)
    at com.google.gson.JsonSerializationVisitor.addAsChildOfObject(JsonSerializationVisitor.java:125)
    at com.google.gson.JsonSerializationVisitor.visitObjectField(JsonSerializationVisitor.java:112)
    at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:164)
    at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:131)
    at com.google.gson.JsonSerializationVisitor.getJsonElementForChild(JsonSerializationVisitor.java:147)
    at com.google.gson.JsonSerializationVisitor.addAsChildOfObject(JsonSerializationVisitor.java:125)
    at com.google.gson.JsonSerializationVisitor.visitObjectField(JsonSerializationVisitor.java:112)
    at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:164)
    at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:131)
    at com.google.gson.JsonSerializationContextDefault.serialize(JsonSerializationContextDefault.java:56)
    at com.google.gson.Gson.toJsonTree(Gson.java:233)
    at com.google.gson.Gson.toJson(Gson.java:273)
    at com.google.gson.Gson.toJson(Gson.java:253)
    at com.htsoft.oa.action.structuringdatamanage.TableargAction.get(TableargAction.java:142)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:404)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:267)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:229)
    at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:221)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:150)
    at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:48)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:123)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:184)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:105)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:83)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:207)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:74)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:127)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at org.apache.struts2.interceptor.ProfilingActivationInterceptor.intercept(ProfilingActivationInterceptor.java:107)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:206)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:115)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:143)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:121)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:170)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:123)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
    at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
    at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
    at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:50)
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:504)
    ... 68 more

解决办法：

在有循环引用的属性上使用transient修饰也可解决，例如：

private transient Dbarg dbarg;

关于json序列化循环引用导致出错