Arthasa是個好東西，用熟了確實一大助力，本文主要描述如何用Arthasa解決問題（官網https://alibaba.github.io/arthas）。
簡單說下安裝，執行如下命令即可：
curl -L https://alibaba.github.io/arthas/install.sh | sh
下載完成後，會出現一個as.sh的文件，直接運行他
./as.sh
直接輸入編號即可，如1，偶爾會遇到更新，如下：
這裏有個類似top的命令叫dashboard，由於我本地輸出太多，這裏借用官網的圖
以下詳細介紹幾個有意思的命令
1、watch
比如我有一個類叫CinemaController，其中有一個無慘方法叫list，那麼命令如下
watch com.lumiai.admin.controller.CinemaController list returnObj
實際應用中，大部分情況是希望觀察到入參和出參，其命令如下：
watch com.lumiai.admin.controller.CinemaController editDesc "{params,returnObj}" -x 3
注意最後的x參數，代表的是展示數據的深度，如果把3改成2，則如下：
另外如果想要查看異常，則執行如下命令
watch com.lumiai.admin.controller.CinemaController editDesc "{params,throwExp}" -e -x 3這裏也借用下官網的圖
$ watch com.alibaba.sample.petstore.biz.impl.UserManagerImpl testAdd "{params, throwExp}" -e -x 2
Press Ctrl+C to abort.
Affect(class-cnt:1 , method-cnt:1) cost in 29 ms.
@ArrayList[
@Object[][
@String[aaa],
@String[bbb],
],
java.lang.NullPointerException
at com.alibaba.sample.petstore.biz.impl.UserManagerImpl.testAdd(UserManagerImpl.java:75)
at com.alibaba.sample.petstore.biz.impl.UserManagerImpl.register(UserManagerImpl.java:60)
at com.alibaba.sample.petstore.web.user.module.action.RegisterAction.doRegister(RegisterAction.java:45)
at com.alibaba.sample.petstore.web.user.module.action.RegisterAction$$FastClassByCGLIB$$ad5428f1.invoke(<generated>)
at net.sf.cglib.reflect.FastMethod.invoke(FastMethod.java:53)
at com.alibaba.citrus.service.moduleloader.impl.adapter.MethodInvoker.invoke(MethodInvoker.java:70)
at com.alibaba.citrus.service.moduleloader.impl.adapter.AbstractModuleEventAdapter.executeAndReturn(AbstractModuleEventAdapter.java:100)
at com.alibaba.citrus.service.moduleloader.impl.adapter.AbstractModuleEventAdapter.execute(AbstractModuleEventAdapter.java:58)
at com.alibaba.citrus.turbine.pipeline.valve.PerformActionValve.invoke(PerformActionValve.java:63)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invokeNext(PipelineImpl.java:157)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invoke(PipelineImpl.java:210)
at com.alibaba.citrus.service.pipeline.impl.valve.ChooseValve.invoke(ChooseValve.java:98)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invokeNext(PipelineImpl.java:157)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invoke(PipelineImpl.java:210)
at com.alibaba.citrus.service.pipeline.impl.valve.LoopValve.invokeBody(LoopValve.java:105)
at com.alibaba.citrus.service.pipeline.impl.valve.LoopValve.invoke(LoopValve.java:83)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invokeNext(PipelineImpl.java:157)
at com.alibaba.citrus.turbine.pipeline.valve.PageAuthorizationValve.invoke(PageAuthorizationValve.java:105)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invokeNext(PipelineImpl.java:157)
at com.alibaba.citrus.turbine.pipeline.valve.CheckCsrfTokenValve.invoke(CheckCsrfTokenValve.java:123)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invokeNext(PipelineImpl.java:157)
at com.alibaba.citrus.turbine.pipeline.valve.AnalyzeURLValve.invoke(AnalyzeURLValve.java:126)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invokeNext(PipelineImpl.java:157)
at com.alibaba.citrus.turbine.pipeline.valve.SetLoggingContextValve.invoke(SetLoggingContextValve.java:66)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invokeNext(PipelineImpl.java:157)
at com.alibaba.citrus.turbine.pipeline.valve.PrepareForTurbineValve.invoke(PrepareForTurbineValve.java:52)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invokeNext(PipelineImpl.java:157)
at com.alibaba.citrus.service.pipeline.impl.PipelineImpl$PipelineContextImpl.invoke(PipelineImpl.java:210)
at com.alibaba.citrus.webx.impl.WebxControllerImpl.service(WebxControllerImpl.java:43)
at com.alibaba.citrus.webx.impl.WebxRootControllerImpl.handleRequest(WebxRootControllerImpl.java:53)
at com.alibaba.citrus.webx.support.AbstractWebxRootController.service(AbstractWebxRootController.java:165)
at com.alibaba.citrus.webx.servlet.WebxFrameworkFilter.doFilter(WebxFrameworkFilter.java:152)
at com.alibaba.citrus.webx.servlet.FilterBean.doFilter(FilterBean.java:148)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.alibaba.citrus.webx.servlet.SetLoggingContextFilter.doFilter(SetLoggingContextFilter.java:61)
at com.alibaba.citrus.webx.servlet.FilterBean.doFilter(FilterBean.java:148)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at com.taobao.tomcat.valves.ContextLoadFilterValve.invoke(ContextLoadFilterValve.java:152)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:429)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1760)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1719)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745),
]其它還有如按耗時篩選，返回異常等，可參照以下鏈接https://alibaba.github.io/arthas/watch.html
2、trace
如果想要看到一個方法的調用鏈以及耗時，最簡單的命令就是
trace com.lumiai.admin.controller.CinemaController editDesc
結果如下：
另外支持按響應時間篩選和條件篩選
3、stack
stack與trace的區別在於，stack會詳細打印出所有堆棧，並且可以根據條件去篩選你想要的那次調用
比如我的方法是根據id查詢，我的命令是需要查詢id=12的調用，那麼命令如下
stack com.lumiai.admin.controller.CinemaController editDesc 'params[0]=="12"'
結果
$ stack com.lumiai.admin.controller.CinemaController editDesc 'params[0]=="12"'
Press Ctrl+C to abort.
Affect(class-cnt:1 , method-cnt:1) cost in 111 ms.
ts=2018-09-30 12:02:01;thread_name=qtp876420389-172;id=ac;is_daemon=false;priority=5;TCCL=org.springframework.boot.loader.LaunchedURLClassLoader@3af49f1c
@sun.reflect.NativeMethodAccessorImpl.invoke0()
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:860)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1650)
at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:206)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.springframework.boot.web.filter.ApplicationContextHeaderFilter.doFilterInternal(ApplicationContextHeaderFilter.java:55)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61)
at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:110)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter.doFilterInternal(OpenEntityManagerInViewFilter.java:178)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.springframework.boot.actuate.autoconfigure.MetricsFilter.doFilterInternal(MetricsFilter.java:106)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:190)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:188)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1253)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:168)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:166)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1155)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.Server.handle(Server.java:530)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:347)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:256)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:247)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce(EatWhatYouKill.java:140)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131)
at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:382)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:708)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:626)
at java.lang.Thread.run(Thread.java:748)基於如上命令，就可以基本的定位某次請求異常時出現的問題，並推斷根源。
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