How can parameter be dynamically obtained in JMeter?

JMeter can achieve dynamic parameter extraction using the following methods:

1. By utilizing JMeter’s built-in functions, you can dynamically retrieve parameters. For example, using the __time function allows you to get the current timestamp, while the __UUID function can generate unique UUIDs. These functions can be used in parameterized fields to dynamically generate parameters.
2. By utilizing JMeter’s PreProcessor, one can dynamically generate parameters before executing a request. Scripts in languages such as BeanShell, JavaScript, or Groovy can be used to write the PreProcessor for generating dynamic parameters.
3. With JMeter’s PostProcessor, you can dynamically extract parameters after a request has been made. For example, you can use regular expressions to extract specific values from the response and use them as parameters in subsequent requests.
4. Utilizing external data files: You can store parameters in an external data file, such as a CSV or Excel file. Then, use the CSV Data Set Config element in JMeter to read the file and dynamically extract parameters.
5. Utilize custom variables in JMeter: You can define custom variables using the User Defined Variables element in JMeter, and use these variables in various requests within your test plan. You can set initial values in the user-defined variables, and dynamically change them as needed.

The above are some common methods for dynamically retrieving parameters. Choose the appropriate method based on your specific needs and scenarios.