赌你半天都想不出的Bug

喜欢ヅ旅行 2022-06-14 07:57 131阅读 0赞

赌你半天都想不出的Bug

##  背景： ##

之前实现一个办公系统，对查询进行一个更改，添加一个“QueryHelper”类，但是代码改完之后，结果一直都没有出来，宝宝心急了，这是怎么回事？

## 问题一： ##

![Center][]

Struts Problem Report

Struts has detected an unhandled exception:

<table> 
 <tbody> 
 <tr> 
 <td> Messages: </td> 
 <td> ·&nbsp; node to traverse cannot be null! </td> 
 </tr> 
 <tr> 
 <td> File: </td> 
 <td> org/hibernate/hql/ast/util/NodeTraverser.java </td> 
 </tr> 
 <tr> 
 <td> Line number: </td> 
 <td> 63 </td> 
 </tr> 
 </tbody> 
</table>

--------------------

Stacktraces

**java.lang.IllegalArgumentException: node to traversecannot be null!**

org.hibernate.hql.ast.util.NodeTraverser.traverseDepthFirst(NodeTraverser.java:63)

org.hibernate.hql.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:280)

org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:182)

org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136)

org.hibernate.engine.query.HQLQueryPlan.(HQLQueryPlan.java:101)

org.hibernate.engine.query.HQLQueryPlan.(HQLQueryPlan.java:80)

org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:124)

org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:156)

org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:135)

org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1770)

cn.itcast.oa.base.DaoSupportImpl.getPageBean(DaoSupportImpl.java:128)

sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

java.lang.reflect.Method.invoke(Method.java:601)

org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)

org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)

org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)

org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)

org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)

org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)

com.sun.proxy.$Proxy20.getPageBean(Unknown Source)

cn.itcast.oa.view.action.ForumAction.show(ForumAction.java:153)

sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

java.lang.reflect.Method.invoke(Method.java:601)

com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441)

com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243)

com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165)

com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252)

org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)

com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)

com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)

com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)

com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

cn.itcast.oa.util.CheckPrivilegeInterceptor.intercept(CheckPrivilegeInterceptor.java:43)

com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)

org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488)

org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)

org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)

org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)

org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)

org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218)

org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)

org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)

org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)

org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)

org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)

org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)

org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)

org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)

org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)

org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2549)

org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2538)

java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

java.lang.Thread.run(Thread.java:722)

--------------------

You are seeing this page because development mode is enabled. Developmentmode, or devMode, enables extra debugging behaviors and reports to assistdevelopers. To disable this mode, set:

struts.devMode=false

in your WEB-INF/classes/struts.properties file.

### 问题分析： ###

出现这种问题，经过主要的语句：“node to traverse cannot be null!” 和相关的语句提示，我们可以分析出，主要是HQL语句出问题了，引起内部的查询对象为空，无法处理控制引起的。解决方案很简单：检查HQL语句（尤其是关键字呗）

![Center 1][]

## 问题二： ##

Struts Problem Report

Struts has detected an unhandled exception:

<table> 
 <tbody> 
 <tr> 
 <td> Messages: </td> 
 <td> ·&nbsp; Topict is not mapped [FROM Topict WHERE t.forum=? ORDER BY (CASE t.type WHEN 2 THEN 2 ELSE 0 END) DESC, t.lastUpdateTime DESC] </td> 
 </tr> 
 <tr> 
 <td> File: </td> 
 <td> org/hibernate/hql/ast/util/SessionFactoryHelper.java </td> 
 </tr> 
 <tr> 
 <td> Line number: </td> 
 <td> 180 </td> 
 </tr> 
 </tbody> 
</table>

--------------------

Stacktraces

**org.hibernate.hql.ast.QuerySyntaxException:Topict is not mapped \[FROM Topict WHERE t.forum=? ORDER BY (CASE t.type WHEN 2THEN 2 ELSE 0 END) DESC, t.lastUpdateTime DESC\]**

org.hibernate.hql.ast.util.SessionFactoryHelper.requireClassPersister(SessionFactoryHelper.java:180)

org.hibernate.hql.ast.tree.FromElementFactory.addFromElement(FromElementFactory.java:111)

org.hibernate.hql.ast.tree.FromClause.addFromElement(FromClause.java:93)

org.hibernate.hql.ast.HqlSqlWalker.createFromElement(HqlSqlWalker.java:322)

org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3441)

org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:3325)

org.hibernate.hql.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:733)

org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:584)

org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:301)

org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:244)

org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:254)

org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:185)