java.lang.reflect.InvocationTargetException异常处理方法

加了一个mapper.xml文件后发生如下异常:

java.lang.reflect.InvocationTargetException
	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:606)
	com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:450)
	com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:289)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:252)
	org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
	org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:249)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:249)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:252)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
	org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:562)
	org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
	org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
root cause

java.lang.NoClassDefFoundError: Could not initialize class com.baizhi.utils.DBUtils
	com.baizhi.service.impl.BookServiceImpl.<init>(BookServiceImpl.java:13)
	com.baizhi.action.BookAction.show(BookAction.java:77)
	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:606)
	com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:450)
	com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:289)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:252)
	org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
	org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:249)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:249)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:252)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
	org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:562)
	org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
	org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)

解决办法: 将mapper.xml文件里的jdbcType=NUMBER改成jdbcType=NUMERIC

总结: 出现该错误时,检查mapper映射文件里是否有地方写错了,比如jdbcType有空值或者值写错了,如果没有写错,检查association标签里是否明确了resultType类型