我想得到按流量来排序，而且还是倒序，怎么达到实现呢？
达到下面这种效果，
默认是根据key来排，
我想根据value里的某个排，
解决思路:将value里的某个，放到key里去，然后来排
下面，开始weekend110的hadoop的自定义排序实现
将FlowSortMapper、FlowSortReduce、FlowSortRunner、FlowSortBean，全放到一个SortMR里。
V2我们不要，怎么写代码？
那么，我们想要实现由
达到下面这种效果，
也要修改FlowBean代码
多领悟揣摩。
关于SotrMR和FlowBean(增改过的)
关于FlowMapper、FlowReducer、FlowSumRunner、FlowBean
之间的对比
[hadoop@weekend110 ~]$ /home/hadoop/app/hadoop-2.4.1/bin/hadoop fs -cat /flow/sortoutput/part-r-00000
13726238888 2481 24681 27162
13726230503 2481 24681 27162
13925057413 63 11058 11121
18320173382 18 9531 9549
13502468823 102 7335 7437
13660577991 9 6960 6969
13922314466 3008 3720 6728
13560439658 5892 400 6292
84138413 4116 1432 5548
15013685858 27 3659 3686
15920133257 20 3156 3176
13602846565 12 1938 1950
15989002119 3 1938 1941
13926435656 1512 200 1712
18211575961 12 1527 1539
13560436666 954 200 1154
13480253104 180 200 380
13760778710 120 200 320
13826544101 0 200 200
13926251106 0 200 200
13719199419 0 200 200
默认分组是哈希，
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* Licensed to the Apache Software Foundation (ASF) under one
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* to you under the Apache License, Version 2.0 (the
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* with the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.hadoop.mapred.lib;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.mapred.Partitioner;
import org.apache.hadoop.mapred.JobConf;
/**
* Partition keys by their {@link Object#hashCode()}.
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public class HashPartitioner<K2, V2> implements Partitioner<K2, V2> {
public void configure(JobConf job) {}
/** Use {@link Object#hashCode()} to partition. */
public int getPartition(K2 key, V2 value,
int numReduceTasks) {
return (key.hashCode() & Integer.MAX_VALUE) % numReduceTasks;
}
}
[hadoop@weekend110 ~]$ /home/hadoop/app/hadoop-2.4.1/bin/hadoop jar flowArea.jar cn.itcast.hadoop.mr.areapartition.FlowSumArea /flow/data /flow/areaoutput
以上是weekend110的mr程序中自定义分组的实现
本文转自大数据躺过的坑博客园博客，原文链接：http://www.cnblogs.com/zlslch/p/5896772.html，如需转载请自行联系原作者
