import org.apache.hadoop.mapred.lib.InputSampler; //导入依赖的package包/类
Object[] getPivots(Path input, int numPivs) throws IOException
{
	
	JobConf job = new JobConf();
	job.setInputFormat(KeyValueTextInputFormat.class);
	job.setMapOutputKeyClass(Text.class);
	org.apache.hadoop.mapred.FileInputFormat.addInputPath(job, input);
	final KeyValueTextInputFormat inf = (KeyValueTextInputFormat) job.getInputFormat();
	InputSampler.Sampler<Text, Text> sampler = new InputSampler.RandomSampler<Text, Text>(1.0, numPivs, 100);
	Object[] samples = sampler.getSample(inf, job);
	return samples;
}