CCIE试验备考之交换STP(2)

当我们在处理mr问题的时候，有时候需求过于复杂，通过一个简单的mr无法达到目的，我们该怎么办呢？
答案是采取JobControl，直接上代码。

/**
* job2 依赖于 job1
* @param job1
* @param job2
* @param chainName
* @return
* @throws IOException
*/
public static int handleJobChain(Job job1 ,Job job2, String chainName) throws IOException{
ControlledJob controlledJob1 = new ControlledJob(job1.getConfiguration());
controlledJob1.setJob(job1);

ControlledJob controlledJob2 = new ControlledJob(job2.getConfiguration());
controlledJob2.setJob(job2);
controlledJob2.addDependingJob(controlledJob1);

JobControl jc = new JobControl(chainName);
jc.addJob(controlledJob1);
jc.addJob(controlledJob2);
Thread jcThread = new Thread(jc);
jcThread.start();
while(true){
if(jc.allFinished()){
System.out.println(jc.getSuccessfulJobList());
jc.stop();
return 0;
}
if(jc.getFailedJobList().size() > 0){
System.out.println(jc.getFailedJobList());
jc.stop();
return 1;
}
}
}

 

要注意的地方就是hadoop的JobControl类实现了线程Runnable接口。我们需要实例化一个线程来让它启动。直接调用JobControl的run()方法，线程将无法结束。