Master JMeter Header Manipulation with Groovy: A Step‑by‑Step Guide

The author has previously published several JMeter tutorials and now provides a complete demo on handling HTTP headers in JMeter using Groovy scripts.

Prerequisites and Test Plan Setup

Create a simple Thread Group with a basic HTTP Request. Then add a JSR223 PreProcessor (post‑processor will be needed for the next request) and attach an HTTP Header Manager to the sampler.

Adding the JSR223 PreProcessor

Insert a JSR223 PreProcessor under the HTTP Request and select groovy as the language.

Groovy Script for Header Management

import org.apache.jmeter.protocol.http.control.*

def manager = sampler.getHeaderManager()
manager.add(new Header("FunTester", "FunTester"))

def h = manager.get(0)
log.info("-------Header : " + h.getName() + "----------- " + h.getValue())

h.setValue("FunTester039029309230")
log.info("-------Header : " + h.getName() + "----------- " + h.getValue())

Sample Console Output

2020-03-19 21:08:23,928 INFO o.a.j.e.StandardJMeterEngine: Running the test!
...
2020-03-19 21:08:24,101 INFO o.a.j.m.J.处理Header: -------Header : FunTester----------- FunTester
2020-03-19 21:08:24,102 INFO o.a.j.m.J.处理Header: -------Header : FunTester----------- FunTester039029309230
...

Viewing the Result

After the test runs, open the View Results Tree listener to verify that the header was added and then modified as expected.

The article also lists other related JMeter tutorials (e.g., handling cookies, variables, command execution, regex extraction, and throughput error analysis) for readers who want to explore further.