java初学笔记

1. struts2中需要注意的几个文件的位置不要放错：

web.xml：在web-inf目录下面

struts.xml：在src目录下面

2. strut2的类型转换中属性文件的位置一定不要放错，否则会出现类似这样的错误(这样的问题一定要避免----切记；*Action-conversion.properties中的配置：action类中的需转型的对象=包.转换器类)：

   严重: Problem loading properties for org.hbnu.hjj.action.LoginAction

   java.lang.ClassNotFoundException: org.hbnu.hjj.converter

at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1363)

at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1209)

at com.opensymphony.xwork2.util.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:147)

at com.opensymphony.xwork2.ObjectFactory.getClassInstance(ObjectFactory.java:100)

at com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:153)

at com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:143)

at com.opensymphony.xwork2.util.XWorkConverter.createTypeConverter(XWorkConverter.java:760)

at com.opensymphony.xwork2.util.XWorkConverter.addConverterMapping(XWorkConverter.java:524)

at com.opensymphony.xwork2.util.XWorkConverter.buildConverterMapping(XWorkConverter.java:725)

at com.opensymphony.xwork2.util.XWorkConverter.getConverter(XWorkConverter.java:397)

at com.opensymphony.xwork2.util.XWorkConverter.convertValue(XWorkConverter.java:275)

at ognl.OgnlRuntime.getConvertedType(OgnlRuntime.java:687)

at ognl.OgnlRuntime.getConvertedTypes(OgnlRuntime.java:703)

at ognl.OgnlRuntime.getConvertedMethodAndArgs(OgnlRuntime.java:726)

at ognl.OgnlRuntime.getAppropriateMethod(OgnlRuntime.java:783)

at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:794)

at ognl.OgnlRuntime.setMethodValue(OgnlRuntime.java:964)

at ognl.ObjectPropertyAccessor.setPossibleProperty(ObjectPropertyAccessor.java:75)

at ognl.ObjectPropertyAccessor.setProperty(ObjectPropertyAccessor.java:131)

at com.opensymphony.xwork2.util.OgnlValueStack$ObjectAccessor.setProperty(OgnlValueStack.java:82)

at ognl.OgnlRuntime.setProperty(OgnlRuntime.java:1656)

at com.opensymphony.xwork2.util.CompoundRootAccessor.setProperty(CompoundRootAccessor.java:44)

at ognl.OgnlRuntime.setProperty(OgnlRuntime.java:1656)

at ognl.ASTProperty.setValueBody(ASTProperty.java:101)

at ognl.SimpleNode.evaluateSetValueBody(SimpleNode.java:177)

at ognl.SimpleNode.setValue(SimpleNode.java:246)

at ognl.Ognl.setValue(Ognl.java:476)

at com.opensymphony.xwork2.util.OgnlUtil.setValue(OgnlUtil.java:186)

at com.opensymphony.xwork2.util.OgnlValueStack.setValue(OgnlValueStack.java:178)

at com.opensymphony.xwork2.util.OgnlValueStack.setValue(OgnlValueStack.java:166)

at com.opensymphony.xwork2.interceptor.ParametersInterceptor.setParameters(ParametersInterceptor.java:230)

at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:176)

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)

at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:421)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)

at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:874)

at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)

at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)

at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)

at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)

at java.lang.Thread.run(Unknown Source)

3. struts2中如果有多个相同的对象需要转换类型，那么要达到这一目的要如何去做：

(1) 在*action中重建相应的setter/getter方法；

(2) 修改属性配置文件：

  ·比较繁琐的方法，但不适用很多个对象转换：也就是写多个例如point=org.hbnu.hjj.converter.PointConverter的语句

·利用全局类型转换的方法(属性文件名为：xwork-conversion.properties.该文件位于src包下，也就是与struts.xml同级目录下):

    包.实体bean=包.转换类  

eg:org.hbnu.hjj.bean.Point=org.hbnu.hjj.converter.PointConverter  

记住：org.apache.struts2.util包下提供了一个StrutsTypeConverter类，进行类型转换。

StrutsTypeConverter这个类提供了几个方法简单的说明一下：

(1)

public Object convertValue(Map context,Object obj,Class toClass)

(2)完成从客户端string类型转为相对应的类型

  public abstract Object convertFromString(Map context,String[] values,  Class toClass)

(3)完成从服务器端到客户端的转换

  public abstract String convertToString(Map context,Object o)