我正在运行一个在作业中有一个分区器类的 hadoop 代码。但是，当我运行命令时
hadoop jar Sort.jar SecondarySort inputdir outputdir
我收到一个运行时错误，上面写着
class KeyPartitioner not org.apache.hadoop.mapred.Partitioner.
我已确保 KeyPartitioner 类扩展了 Partitioner 类，但为什么会出现此错误？
下面是驱动代码：
JobConf conf = new JobConf(getConf(), SecondarySort.class);
conf.setJobName(SecondarySort.class.getName());
conf.setJarByClass(SecondarySort.class);
conf.setInputFormat(TextInputFormat.class);
conf.setOutputFormat(TextOutputFormat.class);
conf.setMapOutputKeyClass(StockKey.class);
conf.setMapOutputValueClass(Text.class);
conf.setPartitionerClass((Class<? extends Partitioner<StockKey, DoubleWritable>>) KeyPartitioner.class);
conf.setMapperClass((Class<? extends Mapper<LongWritable, Text, StockKey, DoubleWritable>>) StockMapper.class);
conf.setReducerClass((Class<? extends Reducer<StockKey, DoubleWritable, Text, Text>>) StockReducer.class);
这是分区器类的代码：
public class KeyPartitioner extends Partitioner<StockKey, Text> {
@Override
public int getPartition(StockKey arg0, Text arg1, int arg2) {
int partition = arg0.name.hashCode() % arg2;
return partition;
}
}