使用mapreduce复制hdfs文件到hbase表

准备工作如下：

一.一张hbase表——fruit(无数据)，一个hdfs本地文件——fruit.tsv(有数据)，我们将使用mapreduce将该本地文件内容写入到hbase的fruit表中。

二.创建包如下

代码如下： 

map端：

public class HdfsMapper extends Mapper<LongWritable, Text, NullWritable, Put> {
	@Override
	protected void map(LongWritable key, Text value,
			Mapper<LongWritable, Text, NullWritable, Put>.Context context)
			throws IOException, InterruptedException {
		String wordString[] = value.toString().split("\t");
		Put put = new Put(Bytes.toBytes(wordString[0]));
		put.addColumn(Bytes.toBytes("info"), Bytes.toBytes("name"),
				Bytes.toBytes(wordString[1]));
		put.addColumn(Bytes.toBytes("info"), Bytes.toBytes("color"),
				Bytes.toBytes(wordString[2]));
		context.write(NullWritable.get(), put);
	}

}

reduce端：

public class HdfsReducer extends TableReducer<NullWritable, Put, NullWritable> {
	@Override
	protected void reduce(NullWritable arg0, Iterable<Put> arg1,
			Reducer<NullWritable, Put, NullWritable, Mutation>.Context arg2)
			throws IOException, InterruptedException {
	for (Put put : arg1) {
		arg2.write( NullWritable.get(),put);
	}
	}
}

drive端：

public class HdfsDriver extends Configuration implements Tool {
	Configuration conf = null;
	@Override
	public void setConf(Configuration conf) {
		this.conf = conf;

	}

	@Override
	public Configuration getConf() {
		// TODO Auto-generated method stub
		return conf;
	}

	@Override
	public int run(String[] args) throws Exception {
		Job job = Job.getInstance(conf);
		job.setJarByClass(HdfsDriver.class);
		job.setMapperClass(HdfsMapper.class);
		job.setMapOutputKeyClass(NullWritable.class);
		job.setMapOutputValueClass(Put.class);
		TableMapReduceUtil
				.initTableReducerJob("fruit", HdfsReducer.class, job);
		FileInputFormat.setInputPaths(job, "/root/fruit.tsv");
		return job.waitForCompletion(true) ? 0 : 1;
	}

	public static void main(String[] args) throws Exception {
		Configuration conf = HBaseConfiguration.create();
		int tool = ToolRunner.run(conf, new HdfsDriver(), args);
		System.exit(tool);
	}
}

运行结果如下：