hive数据文件简单合并

package merge;
import java.io.IOException;
import java.util.Iterator;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.TextInputFormat;
import org.apache.hadoop.mapred.TextOutputFormat;

public class merge
{
public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text, Text>
{
private Text word=new Text("");
public void map(LongWritable key, Text value, OutputCollector<Text, Text> output, Reporter reporter)
throws IOException
{
output.collect(value,word);
}
}

public static void main(String[] args) throws Exception
{
JobConf conf = new JobConf(merge.class);
conf.setJobName("wordcount");
conf.setOutputKeyClass(Text.class);
conf.setOutputValueClass(Text.class);
conf.setMapperClass(Map.class);
conf.setInputFormat(TextInputFormat.class);
conf.setOutputFormat(TextOutputFormat.class);
FileInputFormat.setInputPaths(conf, new Path(args[0]));
FileOutputFormat.setOutputPath(conf, new Path(args[1]));
JobClient.runJob(conf);
}
}

jar打包：在项目的bin目录下
Dev-Fac:bin ce-pc$ jar -cvf hive-merge.jar -C  ../ .

hadoop jar /tmp/hive-merge.jar merge.merge /user/hive/warehouse/table1 /user/hive/warehouse/table1/out

#merge.merge 表示merge包下的merge类