BeanShell PreProcessor
Use BeanShell to operate before the request is made. Syntax usage is the same as BeanShell Sampler. but the available built-in variables are slightly different
Reference example
Jmeter_print current timestamp & print offset timestamp
Jmeter_beanshell implements string encryption
JDBC PreProcessor
Do database operations before the request runs. The usage method is the same as JDBC Request. Application scenarios, such as modifying user information, you need to know the user's information before modification, you can use JDBC PreProcessor to query
User parameters
It is possible to have a variable take a different value in each thread. Can be used in multithreaded testing. For example, when creating a user, the user name cannot be repeated, but multi-threading is required for testing, which can be used at this time.
HTML link parser ( unknown usage to be studied )
HTTP URL rewrite modifiers ( unknown usage for further study )