arthas/arthas-tutorials-en/command/vmtool/vmtool-spring.md

Next, use the vmtool{{}} command to find objects in spring.

Find spring context

vmtool --action getInstances --className org.springframework.context.ApplicationContext {{execute T2}}

Specify the number of expanded layers of returned results

The return result of the getInstances{{}} action is bound to the instances{{}} variable, which is an array.

The expansion level of the result can be specified by the -x{{}} /--expand{{}} parameter, the default value is 1.

vmtool --action getInstances --className org.springframework.context.ApplicationContext -x 2{{execute T2}}

Execute expression

The return result of the getInstances{{}} action is bound to the instances{{}} variable, which is an array. The specified expression can be executed through the --express{{}} parameter.

Find the names of all spring beans:

vmtool --action getInstances --className org.springframework.context.ApplicationContext --express 'instances[0].getBeanDefinitionNames()'{{execute T2}}

Call the userController.findUserById(1){{}} method:

vmtool --action getInstances --className org.springframework.context.ApplicationContext --express 'instances[0].getBean("userController").findUserById(1)'{{execute T2}}

Get userController directly and invoke the method

vmtool --action getInstances --className com.example.demo.arthas.user.UserController --express 'instances[0].findUserById(1)'{{exec}}