MapReduce中map方法write写入参数类型和reduce类型不同
当map方法中context.write()和reduce方法中context.write()输入参数类型不相同时：需要在job中设置每个方法的参数类型：map中：context.write(MyNewKey,NullWritable);reduce中：context.write(LongWritable,LongWritable);那么进行如下设置即可： job
