Java Web 排错日记

今天遇到一个问题如下，看起来像是过滤器的问题：

javax.servlet.ServletException: Filtered request failed.     at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:384)     at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)     at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)     at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)     at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:201)     at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:178)     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)     at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)     at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:223)     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:107)     at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155)     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:75)     at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:934)     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:90)     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:494)     at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1009)     at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:632)     at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)     at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1592)     at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1550)     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)     at java.lang.Thread.run(Thread.java:745) Caused by: java.lang.IllegalArgumentException     at org.apache.catalina.webresources.AbstractResourceSet.checkPath(AbstractResourceSet.java:39)     at org.apache.catalina.webresources.DirResourceSet.getResource(DirResourceSet.java:91)     at org.apache.catalina.webresources.StandardRoot.getResourceInternal(StandardRoot.java:176)     at org.apache.catalina.webresources.CachedResource.validate(CachedResource.java:62)     at org.apache.catalina.webresources.Cache.getResource(Cache.java:78)     at org.apache.catalina.webresources.StandardRoot.getResource(StandardRoot.java:163)     at org.apache.catalina.core.StandardContext.getRealPath(StandardContext.java:4528)     at org.apache.catalina.core.ApplicationContext.getRealPath(ApplicationContext.java:398)     at org.apache.catalina.core.ApplicationContextFacade.getRealPath(ApplicationContextFacade.java:335)     at com.opensymphony.module.sitemesh.mapper.FileDecoratorMapper.getNamedDecorator(FileDecoratorMapper.java:48)     at com.opensymphony.module.sitemesh.mapper.AbstractDecoratorMapper.getNamedDecorator(AbstractDecoratorMapper.java:50)     at com.opensymphony.module.sitemesh.mapper.AbstractDecoratorMapper.getNamedDecorator(AbstractDecoratorMapper.java:50)     at com.opensymphony.module.sitemesh.mapper.AbstractDecoratorMapper.getNamedDecorator(AbstractDecoratorMapper.java:50)     at com.opensymphony.module.sitemesh.mapper.PageDecoratorMapper.getByProperty(PageDecoratorMapper.java:70)     at com.opensymphony.module.sitemesh.mapper.PageDecoratorMapper.getDecorator(PageDecoratorMapper.java:62)     at com.opensymphony.module.sitemesh.mapper.AbstractDecoratorMapper.getDecorator(AbstractDecoratorMapper.java:45)     at com.opensymphony.module.sitemesh.mapper.InlineDecoratorMapper.getDecorator(InlineDecoratorMapper.java:41)     at com.opensymphony.sitemesh.compatability.DecoratorMapper2DecoratorSelector.selectDecorator(DecoratorMapper2DecoratorSelector.java:30)     at com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:83)     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)     at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)     at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)     at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)     at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)     at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)     at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)     ... 29 more 

像这种过滤器抛出的异常，一般是被包装过的，丢失了一部分信息，通过二分法注释 web.xml 中的过滤器，就可以确定出错的过滤器。

另一个思路其实是看 Cased by 后面的第一个调用 org.apache.catalina.webresources.AbstractResourceSet.checkPath，就可以知道是 tomcat 读取项目资源路径的问题，而不是过滤器的问题，通过修改 tomcat 设置或者更换 tomcat 应该就能解决。

Webresources class AbstractResourceSet throws exception upon callong ServletContext.getRealPath(“”)

Tomcat 8, unlike Tomcat 7.0.42, throws IllegalArgumentException upon calling ServletContext.getRealPath(“”). It seems that TC8 expects that argument provided to getRealPath is non-empty string.

I believe that ServletContext.getRealPath should allow empty string as argument.

Wizzercn/NutzWk/issues/18

本地获取tomcat服务器部署路径，但真实服务器获取tomcat部署路径报错