Struts+Spring+Mybatis 写一个web系统 出现Error calling method through OGNL错误，求大神指点指点~

sinat_32529327 2017-04-27 10:03:53 
public String startExam(){

		Paper p=paperService.selectById(paper.getId());

		String paperId =p.getId();

		String courseId = p.getCourseId();

		String modelId = p.getModelId();

		System.out.println(modelId);

		List<ModelDetail> mDetails=

				modelDetailService.selectDetail(modelId);//报错的那一行

	    for(ModelDetail modelDetail : mDetails){

	    	List<Question> questions = 

	    			questionService.selectByRandom(modelDetail.getTypeId(), courseId, modelDetail.getQuantity());

	    	addPaperDetail(questions,paperId);	

	    }

		paperDetails=paperDetailService.selectByPaper(paperId);

		return "enterExam";

	}

2017-04-27 21:52:21,678[http-bio-8080-exec-6]DEBUG[com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor]-Error calling method through OGNL: object: [com.examination.web.PaperAction@7cbf6665] method: [startExam] args: [[]]

java.lang.NullPointerException

	at com.examination.web.PaperAction.startExam(PaperAction.java:101)

	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 ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:870)

	at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1293)

	at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)

	at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117)

	at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108)

	at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369)

	at ognl.ASTMethod.getValueBody(ASTMethod.java:90)

	at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)

	at ognl.SimpleNode.getValue(SimpleNode.java:258)

	at ognl.Ognl.getValue(Ognl.java:494)

	at ognl.Ognl.getValue(Ognl.java:458)

	at com.opensymphony.xwork2.ognl.OgnlUtil$2.execute(OgnlUtil.java:309)

	at com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecute(OgnlUtil.java:340)

	at com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:307)

	at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:423)

	at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:287)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:250)

	at org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)

	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)

	at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76)

	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)

	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)

	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)

	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

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

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)

	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)

	at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)

	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564)

	at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)

	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)

	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)

	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)

	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)

	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)

	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)

	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)

	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)

	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)

	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)

	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1002)

	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)

	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)

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

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

	at java.lang.Thread.run(Thread.java:744)

mapper方法使用mybatis逆向工程写的我觉得应该没什么问题
这个错误报了好几次，前几次都是修改代码的思路，这次真的不知道了
...全文
301 1 打赏 收藏 转发到动态 举报
写回复
用AI写文章
1 条回复
切换为时间正序
请发表友善的回复…
发表回复
我爱娃哈哈 2017-04-27
  • 打赏
  • 举报
 回复
空指针异常，看看是不是参数为空了
struts2.2.3 + spring3.1.0 + mybatis3.1.0集成简单demo
struts2.2.3 + spring3.1.0 + mybatis3.1.0集成简单demo。具体请看：http://blog.csdn.net/afgasdg/article/details/7392367
spring+struts+mybatis+security+memcached+GBAC权限架构开源项目
spring+struts+mybatis+security+memcached+GBAC权限架构开源项目, 懂的自己下载看,不懂的就去问懂的,还有就是有的人说上一个版本的代码有点乱,我只能说你站在你的角度看,我站在我的角度写,说明我们有代沟,大概如此了...补充一点,因为security3对于分布式应用系统有限制,因为没有提供session共享的功能,所以建议大家自己扩展下,这里我就不累赘说
基于ssm(struts+spring+mybatis)失物招领系统
（3）系统简介：主要实现系统简介信息的查看。 （4）失物信息：该模块主要实现失物寻找和发布公告等功能。 （5）在线留言：主要实现在线留言和查看留言功能。 管理员端： （1）系统用户管理：主要实现管理员用户...
SpringMVC+Spring+Mybatis集成开发环境
SpringMVC+Spring+Mybatis集成开发环境
Spring+SpringMVC+MyBatis整合工程实例 完整版源码（带注释）
这个SSM框架整合工程是基于IntelliJ IDEA完成的的，工程里面配置文件均有注释，可直接拷贝使用（工程代码可导入IDEA中直接运行）
Web开发应用服务器

5,655

社区成员

20,181

社区内容

发帖
与我相关
我的任务
社区描述
Web开发应用服务器相关讨论专区
社区管理员
  • 应用服务器社区
加入社区
  • 近7日
  • 近30日
  • 至今

加载中

查看更多榜单
社区公告
暂无公告

试试用AI创作助手写篇文章吧

+ 用AI写文章