JMeter-- ThreadGroup原理分析

JMeterEngine会驱动JMeter ThreadGroup启动Test Threads 执行测试，其本身也是一个Runnable，这里把测试驱动（JUnit或者其他类似main之类的）看作主线程(main thread)的话, JMeterEngine作为第一层子线程(First Child Thread)，所以如果项目代码基于很多模块（比如基于OSGI），需要进行ClassLoader调整的话可以重写JMeterEngine的runTest方法，例如.:

public void runTest() throws JMeterEngineException
{
    try {
        tcClassloader = Thread.currentThread().getContextClassLoader();  

        Future<?> f = DefaultExecutorService.getInstance().submit(this);
        f.get();
    }
    catch (Exception err) {
        stopTest();
        throw new JMeterEngineException(err);
    }
    finally {  

    }
}  

              @Override
public void run()
{
    ClassLoader oldCl = Thread.currentThread().getContextClassLoader();
    Thread.currentThread().setContextClassLoader(tcClassloader);
    try {
        super.run();
    }
    finally {
        Thread.currentThread().setContextClassLoader(oldCl);
    }
}