關於log4j日誌列印堆疊的記錄
----遇到的一個日誌的問題，與這位同學遇到的差不多，遂轉載
轉自：
https://blog.csdn.net/weiweiai123456/article/details/72864838
記錄下日誌小細節，逗號和加號在日誌檔案裡的區別
引入jar包：
上程式碼：
這裡實際記錄到日誌檔案裡的日誌資訊是不同的，前者為
逗號在日誌檔案裡體現：
-
2017-06-05 10:33:56 [ERROR] [com.cooya.health.controller.category.CategoryController.updateStatus:159] |【逗號】測試錯誤堆疊到日誌檔案 -
java.lang.NullPointerException: null -
at com.cooya.health.controller.common.BaseController.getUserName(BaseController.java:48) -
at com.cooya.health.controller.category.CategoryController.updateStatus(CategoryController.java:155) -
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:601) -
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) -
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) -
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) -
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:832) -
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:743) -
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) -
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:961) -
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:895) -
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967) -
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:869) -
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641) -
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843) -
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) -
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304) -
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) -
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) -
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) -
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) -
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) -
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) -
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) -
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) -
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262) -
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) -
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) -
at org.jasig.cas.client.session.SingleSignOutFilter.doFilter(SingleSignOutFilter.java:76) -
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) -
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) -
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121) -
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) -
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:224) -
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:185) -
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:151) -
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100) -
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929) -
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) -
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405) -
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:269) -
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515) -
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302) -
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) -
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) -
at java.lang.Thread.run(Thread.java:722)
原因：
void error(String var1, Throwable var2);
第二個引數為Throwable，為Exception的超類。
而如果寫成加號形式，則為：
2017-06-05 10:33:56 [ERROR] [com.cooya.health.controller.category.CategoryController.updateStatus:160] |【加號】這裡是測試錯誤資訊列表java.lang.NullPointerException這是因為：
void error(String var1);相當於拼接字串了，所以加號和逗號對於日誌儲存差異很大。
mark一個知識，也是基礎細節。Exception e
e.getMessage();
e.toString();的區別，一張圖表達。
總結：細節決定程式碼差距，以前這裡都沒有注意，感覺逗號和加號差不多，在生產中調取日誌檔案才發現沒有堆疊資訊。