arthas/tutorials/katacoda/arthas-advanced-en/case-get-spring-context.md

In this case, the user can get the spring context, get the bean, and invoke the method.

Use the tt command to record the invocation of the specified method

tt is TimeTunnel, which records the parameters and return value of each invocation of the specified method.

• https://alibaba.github.io/arthas/tt.html

tt -t org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter invokeHandlerMethod{{execute T2}}

Visit: https://HOST_SUBDOMAIN-80-KATACODA_HOST.environments.katacoda.com/user/1

You can see that the tt command record an invocation:

$ tt -t org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdaptePress Q or Ctrl+C to abort.
Affect(class-cnt:1 , method-cnt:1) cost in 252 ms.
 INDE  TIMESTAMP    COST(  IS-R  IS-  OBJECT     CLASS               METHOD
 X                  ms)    ET    EXP
-----------------------------------------------------------------------------------------
 1000  2019-02-15   4.583  true  fal  0xc93cf1a  RequestMappingHand  invokeHandlerMethod
       15:38:32     923          se              lerAdapter

Use the tt command to get the spring context from the invocation record.

Type Q{{execute T2}} or Ctrl + C to exit the tt -t command above.

tt -i 1000 -w 'target.getApplicationContext()'{{execute T2}}

$ tt -i 1000 -w 'target.getApplicationContext()'
@AnnotationConfigEmbeddedWebApplicationContext[
    reader=@AnnotatedBeanDefinitionReader[org.springframework.context.annotation.AnnotatedBeanDefinitionReader@2e457641],
    scanner=@ClassPathBeanDefinitionScanner[org.springframework.context.annotation.ClassPathBeanDefinitionScanner@6eb38026],
    annotatedClasses=null,
    basePackages=null,
]
Affect(row-cnt:1) cost in 439 ms.

Get the spring bean and invoke method

tt -i 1000 -w 'target.getApplicationContext().getBean("helloWorldService").getHelloMessage()'{{execute T2}}

The result is:

$ tt -i 1000 -w 'target.getApplicationContext().getBean("helloWorldService").getHelloMessage()'
@String[Hello World]
Affect(row-cnt:1) cost in 52 ms.