执行 ：curl http://localhost:8089/admin 结果是：

  1. {"timestamp":1577088866157,"status":401,"error":"Unauthorized","message":"admin filter error.","path":"/admin"}

401通常是被权限管理的Filter拦截了，那么到底是哪个Filter处理了这个请求，返回了401？

跟踪所有的Filter函数

trace javax.servlet.Filter *
执行： curl http://localhost:8089/admin
可以在调用树的最深层，找到AdminFilterConfig$AdminFilter返回了401：

+---[3.806273ms] javax.servlet.FilterChain:doFilter()
|   `---[3.447472ms] com.example.demo.arthas.AdminFilterConfig$AdminFilter:doFilter()
|       `---[0.17259ms] javax.servlet.http.HttpServletResponse:sendError()

通过stack获取调用栈

上面是通过trace命令来获取信息，从结果里，我们可以知道通过stack跟踪HttpServletResponse:sendError()，同样可以知道是哪个Filter返回了401
执行：stack javax.servlet.http.HttpServletResponse sendError 'params[0]==401'
执行： curl http://localhost:8089/admin

$ stack javax.servlet.http.HttpServletResponse sendError 'params[0]==401'
Press Q or Ctrl+C to abort.
Affect(class-cnt:2 , method-cnt:4) cost in 87 ms.
ts=2019-02-15 16:44:06;thread_name=http-nio-8080-exec-6;id=16;is_daemon=true;priority=5;TCCL=org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedWebappClassLoader@8546cd5
    @org.apache.catalina.connector.ResponseFacade.sendError()
        at com.example.demo.arthas.AdminFilterConfig$AdminFilter.doFilter(AdminFilterConfig.java:38)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)