org.apache.hadoop. hadoop.io. longwritable不能被强制转换为org.apache

Question

我是Hadoop的新手。我使用hadoop 2.3.0和hbase 0.98.3。我试图通过使用MapReduce从文本文件中提取数据并写入hadoop中的hbase表。虽然我设置了outputKeyClass和outputValueClass的工作，我得到classCastException。有人能帮我吗?

这是我的代码。

public static void main(String[] args) {
    Configuration config = HBaseConfiguration.create();
    Job job;
    try {
        job = new Job(config, "LogBulkLoader");
        job.setJarByClass(Main.class);
        job.setMapperClass(LogMapper.class);
        job.setOutputFormatClass(TableOutputFormat.class);
        job.getConfiguration().set(TableOutputFormat.OUTPUT_TABLE, "fatih");
        job.setOutputKeyClass(ImmutableBytesWritable.class);
        job.setOutputValueClass(Put.class);
        FileInputFormat.addInputPath(job, new Path(userActionsTestFile));
        job.setNumReduceTasks(0);
        job.waitForCompletion(true);
    } catch (IOException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}
public static class LogMapper extends
        TableMapper<ImmutableBytesWritable, Put> {
    @Override
    protected void setup(Context context) throws IOException,
            InterruptedException {
    }
    @Override
    protected void map(ImmutableBytesWritable key, Result value,
            Context context) throws IOException, InterruptedException {
        try {
            String[] l = value.toString().split(",");
            String[] t = l[4].split(" ");
            String[] date = t[0].split("-");
            String[] time = t[1].split(":");
            GregorianCalendar gc = new GregorianCalendar(
                    Integer.parseInt(date[0]), Integer.parseInt(date[1]),
                    Integer.parseInt(date[2]), Integer.parseInt(time[0]),
                    Integer.parseInt(time[1]), Integer.parseInt(time[2]));
            Put put = new Put(Bytes.toBytes(l[0]));
            put.add(Bytes.toBytes("song"), Bytes.toBytes(l[1]),
                    gc.getTimeInMillis(), Bytes.toBytes(l[6]));
            put.add(Bytes.toBytes("album"), Bytes.toBytes(l[1]),
                    gc.getTimeInMillis(), Bytes.toBytes(l[5]));
            put.add(Bytes.toBytes("album"), Bytes.toBytes(l[2]),
                    gc.getTimeInMillis(), Bytes.toBytes(l[5]));
            put.add(Bytes.toBytes("singer"), Bytes.toBytes(l[1]),
                    gc.getTimeInMillis(), Bytes.toBytes(l[5]));
            put.add(Bytes.toBytes("singer"), Bytes.toBytes(l[2]),
                    gc.getTimeInMillis(), Bytes.toBytes(l[5]));
            put.add(Bytes.toBytes("singer"), Bytes.toBytes(l[3]),
                    gc.getTimeInMillis(), Bytes.toBytes(l[5]));
            context.write(new ImmutableBytesWritable(l[0].getBytes()), put);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

得到如下异常:

java.lang.Exception: java.lang.ClassCastException: org.apache.hadoop.io.LongWritable cannot be cast to org.apache.hadoop.hbase.io.ImmutableBytesWritable
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:403)
Caused by: java.lang.ClassCastException: org.apache.hadoop.io.LongWritable cannot be cast to org.apache.hadoop.hbase.io.ImmutableBytesWritable
at com.argedor.module1.Main$LogMapper.map(Main.java:1)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:145)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:763)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339)
at org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:235)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)

Answer 1

添加以下代码

  job.setMapOutputKeyClass(ImmutableBytesWritable.class)
  job.setMapOutputValueClass(Put.class)