hadoop中用于映射器和组合器的不同上下文类型

Hello I'm trying to implement java hadoop application. I want to make mapper of <Object, Text, NaicsAreaPair, LongWritable> (so the output of mapper will be NaicsAreaPair as key and LongWritable as value). Then I need Combiner to be like <NaicsAreaPair,LongWritable, Text,AreaWagePair> so the input is correct with mapper output, but combiner output is different from mapper output.Hello I'm trying to implement java hadoop appli