用Apache压缩到HBase Standalone中的WordCount

目前,我正在评估Apache Crunch.我遵循一个简单的WordCount MapReduce job example：
之后,我尝试将结果保存到独立的HBase中. HBase正在运行(已通过jps和HBase Shell进行检查),如下所述：http://hbase.apache.org/book/quickstart.html

现在,我采用编写HBase的示例：

Pipeline pipeline = new MRPipeline(WordCount.class,getConf());
PCollection<String> lines = pipeline.readTextFile(inputPath);
PTable<String,Long> counts = noStopWords.count();
pipeline.write(counts, new HBaseTarget("wordCountOutTable");
PipelineResult result = pipeline.done();

我收到异常：“ exception：java.lang.illegalArgumentException：HBaseTarget仅支持放置和删除”

任何线索出了什么问题？

解决方法:

PTable可能是PCollection,但是HBaseTarget只能处理Put或Delete对象.因此,您必须将PTable转换为PCollection,其中集合的每个元素都是Put或Delete.看一下Crunch-Examples完成的地方.

转换示例如下所示：

 public PCollection<Put> createPut(final PTable<String, String> counts) {
   return counts.parallelDo("Convert to puts", new DoFn<Pair<String, String>, Put>() {
     @Override
     public void process(final Pair<String, String> input, final Emitter<Put> emitter) {
       Put put;
       // input.first is used as row key
       put = new Put(Bytes.toBytes(input.first())); 
       // the value (input.second) is added with its family and qualifier
       put.add(COLUMN_FAMILY_TARGET, COLUMN_QUALIFIER_TARGET_TEXT, Bytes.toBytes(input.second())); 
       emitter.emit(put);
     }
   }, Writables.writables(Put.class));
 }