SLF4J列印日誌注意點--加號逗號區別
阿新 • • 發佈：2018-12-17
1.使用SLF4J列印日誌，它有一個佔位符“{}”一般不是異常這樣列印
logger.info("InvestmentFacadeImpl queryInvestmentInfo: investmentListResponse is {}", investmentListResponse);
{}就是一個佔位符列印資訊就為：
InvestmentFacadeImpl queryInvestmentInfo: investmentListResponse is********
2.對於異常錯誤的列印日誌 一個錯誤的示範：
logger.error("CrowdFundingAssetServiceImpl insert throws exception is {}", e.getMessage());
看一下error的原始碼
/**
* Log an exception (throwable) at the ERROR level with an
* accompanying message.
*
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
*/
public void error(String msg, Throwable t);
所以對於異常，是不需要佔位符的，而且也不需要e.getMessage()，直接打印出來即可
logger.error("FinancingManualFacadeImpl.addFinancingProduct failed! ", e);
一.logger.error逗號和加號的區別
catch(Exception e){
logger.error("[逗號] 測試錯誤堆疊到日誌檔案"，e);
logger.error("[加號] 這裡是測試錯誤資訊列表"+e);
logger.error("錯誤異常"+e.getmessage);
}
這裡實際記錄到日誌檔案裡的日誌資訊是不同的，前者為 逗號在日誌檔案中的體現
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)
原因為：
void error(String var1, Throwable var2);
第二個引數為Throwable，為Exception的超類。
2.加號形式：
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
原因：
void error(String var1)
相當於拼接字串了
二. e.getmessage和e.tostring 區別 錯誤異常null ------e.getMessage 錯誤異常java.lang.NullpoiterException