= HelloHadoopV2.java = 

{{{
#!java
package org.nchc.hadoop;
import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;	

public class HelloHadoopV2 {


	public static void main(String[] args) throws IOException,
			InterruptedException, ClassNotFoundException {

		Configuration conf = new Configuration();
		Job job = new Job(conf, "Hadoop Hello World 2");
		job.setJarByClass(HelloHadoopV2.class);
		// 設定 map and reduce 以及 Combiner class
		job.setMapperClass(HelloMapperV2.class);
		job.setCombinerClass(HelloReducerV2.class);
		job.setReducerClass(HelloReducerV2.class);

		// 設定map的輸出型態
		job.setMapOutputKeyClass(Text.class);
		job.setMapOutputValueClass(Text.class);
		// 設定reduce的輸出型態
		job.setOutputKeyClass(Text.class);
		job.setOutputValueClass(Text.class);

		FileInputFormat.addInputPath(job, new Path("/user/hadoop/input"));

		FileOutputFormat.setOutputPath(job, new Path("/user/hadoop/output-hh2"));

		// 呼叫checkAndDelete函式，檢查是否存在該資料夾，若有則刪除之
		CheckAndDelete.checkAndDelete("/user/hadoop/output-hh2", conf);

		boolean status = job.waitForCompletion(true);

		if (status) {
			System.err.println("Integrate Alert Job Finished !");

		} else {
			System.err.println("Integrate Alert Job Failed !");
			System.exit(1);
		}
	}
}

}}}