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);  
    }  
}