MapReduce实战（三）分区的实现

需求：

在实战（一）的基础 上，实现自定义分组机制。例如根据手机号的不同，分成不同的省份，然后在不同的reduce上面跑，最后生成的结果分别存在不同的文件中。

对流量原始日志进行流量统计，将不同省份的用户统计结果输出到不同文件。

思考：

需要自定义改造两个机制：
1、改造分区的逻辑，自定义一个partitioner，主要是实现如何进行分组。

Partitioner的作用是对Mapper产生的中间结果进行分片，以便将同一个分区的数据交给同一个Reducer处理，它直接影响Reducer阶段的负载均衡。
    Partitioner只提供了一个方法：
    getPartition(Text key,Text value,int numPartitions)
    前两个参数是Map的Key和Value，numPartitions为Reduce的个数。


2、自定义reducer task的并发任务数，使得多个reduce同时工作。

项目目录如下：

AreaPartition.java:

package cn.darrenchan.hadoop.mr.areapartition;

import java.util.HashMap;

import org.apache.hadoop.mapreduce.Partitioner;

public class AreaPartitioner<KEY, VALUE> extends Partitioner<KEY, VALUE>{

    private static HashMap<String,Integer> areaMap = new HashMap<>();
    
    /**
     * 这里只是提前设定了一下，其实这里可以写查询数据库，返回号码所在省份的编号
     */
    static{
        areaMap.put("135", 0);
        areaMap.put("136", 1);
        areaMap.put("137", 2);
        areaMap.put("138", 3);
        areaMap.put("139", 4);
    }
    
    @Override
    public int getPartition(KEY key, VALUE value, int numPartitions) {
        //从key中拿到手机号，查询手机归属地字典，不同的省份返回不同的组号
        int areaCoder  = areaMap.get(key.toString().substring(0, 3))==null?5:areaMap.get(key.toString().substring(0, 3));
        return areaCoder;
    }

}

FlowSumArea.java:

package cn.darrenchan.hadoop.mr.areapartition;

import java.io.IOException;

import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import cn.darrenchan.hadoop.mr.flow.FlowBean;

/**
 * 对流量原始日志进行流量统计，将不同省份的用户统计结果输出到不同文件 
 * 需要自定义改造两个机制：
 * 1、改造分区的逻辑，自定义一个partitioner
 * 2、自定义reduer task的并发任务数
 * 
 */
public class FlowSumArea {

    public static class FlowSumAreaMapper extends
            Mapper<LongWritable, Text, Text, FlowBean> {

        @Override
        protected void map(LongWritable key, Text value, Context context)
                throws IOException, InterruptedException {

            // 拿一行数据
            String line = value.toString();
            // 切分成各个字段
            String[] fields = StringUtils.split(line, "	");

            // 拿到我们需要的字段
            String phoneNum = fields[1];
            long upFlow = Long.parseLong(fields[7]);
            long downFlow = Long.parseLong(fields[8]);

            // 封装数据为kv并输出
            context.write(new Text(phoneNum), new FlowBean(phoneNum, upFlow,
                    downFlow));

        }

    }

    public static class FlowSumAreaReducer extends
            Reducer<Text, FlowBean, Text, FlowBean> {

        @Override
        protected void reduce(Text key, Iterable<FlowBean> values,
                Context context) throws IOException, InterruptedException {

            long up_flow_counter = 0;
            long d_flow_counter = 0;

            for (FlowBean bean : values) {

                up_flow_counter += bean.getUpFlow();
                d_flow_counter += bean.getDownFlow();

            }

            context.write(key, new FlowBean(key.toString(), up_flow_counter,
                    d_flow_counter));

        }

    }

    public static void main(String[] args) throws Exception {

        Configuration conf = new Configuration();
        Job job = Job.getInstance(conf);

        job.setJarByClass(FlowSumArea.class);

        job.setMapperClass(FlowSumAreaMapper.class);
        job.setReducerClass(FlowSumAreaReducer.class);

        // 设置我们自定义的分组逻辑定义
        job.setPartitionerClass(AreaPartitioner.class);
　　　　　　 

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(FlowBean.class);

        // 设置reduce的任务并发数，应该跟分组的数量保持一致，写1不会报错，2,3,4,5均会报错，7,8,9...反而不会报错，因为后面的直接数据为0了
        job.setNumReduceTasks(6);

        FileInputFormat.setInputPaths(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

        System.exit(job.waitForCompletion(true) ? 0 : 1);

    }

}

FlowBeanArea.java:

package cn.darrenchan.hadoop.mr.flow;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;

public class FlowBean implements WritableComparable<FlowBean> {
    private String phoneNum;// 手机号
    private long upFlow;// 上行流量
    private long downFlow;// 下行流量
    private long sumFlow;// 总流量

    public FlowBean() {
        super();
    }

    public FlowBean(String phoneNum, long upFlow, long downFlow) {
        super();
        this.phoneNum = phoneNum;
        this.upFlow = upFlow;
        this.downFlow = downFlow;
        this.sumFlow = upFlow + downFlow;
    }

    public String getPhoneNum() {
        return phoneNum;
    }

    public void setPhoneNum(String phoneNum) {
        this.phoneNum = phoneNum;
    }

    public long getUpFlow() {
        return upFlow;
    }

    public void setUpFlow(long upFlow) {
        this.upFlow = upFlow;
    }

    public long getDownFlow() {
        return downFlow;
    }

    public void setDownFlow(long downFlow) {
        this.downFlow = downFlow;
    }

    public long getSumFlow() {
        return sumFlow;
    }

    public void setSumFlow(long sumFlow) {
        this.sumFlow = sumFlow;
    }

    @Override
    public String toString() {
        return upFlow + "	" + downFlow + "	" + sumFlow;
    }

    // 从数据流中反序列出对象的数据
    // 从数据流中读出对象字段时，必须跟序列化时的顺序保持一致
    @Override
    public void readFields(DataInput in) throws IOException {
        phoneNum = in.readUTF();
        upFlow = in.readLong();
        downFlow = in.readLong();
        sumFlow = in.readLong();
    }

    // 将对象数据序列化到流中
    @Override
    public void write(DataOutput out) throws IOException {
        out.writeUTF(phoneNum);
        out.writeLong(upFlow);
        out.writeLong(downFlow);
        out.writeLong(sumFlow);
    }

    @Override
    public int compareTo(FlowBean flowBean) {
        return sumFlow > flowBean.getSumFlow() ? -1 : 1;
    }

}

将项目打包成area.jar，并执行命令：

hadoop jar area.jar cn.darrenchan.hadoop.mr.areapartition.FlowSumArea /flow/srcdata /flow/outputarea

我们可以看到如下运行信息： 

17/02/26 09:10:54 INFO client.RMProxy: Connecting to ResourceManager at weekend110/192.168.230.134:8032
17/02/26 09:10:54 WARN mapreduce.JobSubmitter: Hadoop command-line option parsing not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.
17/02/26 09:10:55 INFO input.FileInputFormat: Total input paths to process : 1
17/02/26 09:10:55 INFO mapreduce.JobSubmitter: number of splits:1
17/02/26 09:10:55 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1488112052214_0005
17/02/26 09:10:55 INFO impl.YarnClientImpl: Submitted application application_1488112052214_0005
17/02/26 09:10:55 INFO mapreduce.Job: The url to track the job: http://weekend110:8088/proxy/application_1488112052214_0005/
17/02/26 09:10:55 INFO mapreduce.Job: Running job: job_1488112052214_0005
17/02/26 09:11:01 INFO mapreduce.Job: Job job_1488112052214_0005 running in uber mode : false
17/02/26 09:11:01 INFO mapreduce.Job: map 0% reduce 0%
17/02/26 09:11:07 INFO mapreduce.Job: map 100% reduce 0%
17/02/26 09:11:19 INFO mapreduce.Job: map 100% reduce 17%
17/02/26 09:11:23 INFO mapreduce.Job: map 100% reduce 33%
17/02/26 09:11:26 INFO mapreduce.Job: map 100% reduce 50%
17/02/26 09:11:27 INFO mapreduce.Job: map 100% reduce 83%
17/02/26 09:11:28 INFO mapreduce.Job: map 100% reduce 100%
17/02/26 09:11:28 INFO mapreduce.Job: Job job_1488112052214_0005 completed successfully
17/02/26 09:11:28 INFO mapreduce.Job: Counters: 49
File System Counters
FILE: Number of bytes read=1152
FILE: Number of bytes written=652142
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=2338
HDFS: Number of bytes written=526
HDFS: Number of read operations=21
HDFS: Number of large read operations=0
HDFS: Number of write operations=12
Job Counters
Launched map tasks=1
Launched reduce tasks=6
Data-local map tasks=1
Total time spent by all maps in occupied slots (ms)=2663
Total time spent by all reduces in occupied slots (ms)=83315
Total time spent by all map tasks (ms)=2663
Total time spent by all reduce tasks (ms)=83315
Total vcore-seconds taken by all map tasks=2663
Total vcore-seconds taken by all reduce tasks=83315
Total megabyte-seconds taken by all map tasks=2726912
Total megabyte-seconds taken by all reduce tasks=85314560
Map-Reduce Framework
Map input records=22
Map output records=22
Map output bytes=1072
Map output materialized bytes=1152
Input split bytes=124
Combine input records=0
Combine output records=0
Reduce input groups=21
Reduce shuffle bytes=1152
Reduce input records=22
Reduce output records=21
Spilled Records=44
Shuffled Maps =6
Failed Shuffles=0
Merged Map outputs=6
GC time elapsed (ms)=524
CPU time spent (ms)=3210
Physical memory (bytes) snapshot=509775872
Virtual memory (bytes) snapshot=2547916800
Total committed heap usage (bytes)=218697728
Shuffle Errors
BAD_ID=0
CONNECTION=0
IO_ERROR=0
WRONG_LENGTH=0
WRONG_MAP=0
WRONG_REDUCE=0
File Input Format Counters
Bytes Read=2214
File Output Format Counters
Bytes Written=526

 运行结果完成之后，我们发现这次生成了6个文件，显示如下：

最终显示结果如下所示，我们看到的确是按照我们预期的进行了相应的分组：

在运行过程中，我们不断监控该过程，看看是不是一共6个reduce同时工作，发现最多的地方确实是6个YarnChild，说明我们的程序正确。

Last login: Sun Feb 26 04:26:01 2017 from 192.168.230.1
[hadoop@weekend110 ~] jps
2473 NameNode
8703 RunJar
9214 Jps
9029 YarnChild
8995 YarnChild
2747 SecondaryNameNode
8978 -- process information unavailable
2891 ResourceManager
2992 NodeManager
8799 MRAppMaster
9053 YarnChild
2569 DataNode
[hadoop@weekend110 ~] jps
2473 NameNode
2747 SecondaryNameNode
2891 ResourceManager
2992 NodeManager
8799 MRAppMaster
2569 DataNode
9330 Jps
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
2747 SecondaryNameNode
2891 ResourceManager
9386 RunJar
2992 NodeManager
2569 DataNode
9495 Jps
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
2747 SecondaryNameNode
2891 ResourceManager
9386 RunJar
9558 Jps
2992 NodeManager
2569 DataNode
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
9580 Jps
2747 SecondaryNameNode
2891 ResourceManager
9386 RunJar
2992 NodeManager
2569 DataNode
[hadoop@weekend110 ~] jps
2473 NameNode
9598 YarnChild
9482 MRAppMaster
2747 SecondaryNameNode
9623 Jps
2891 ResourceManager
9386 RunJar
2992 NodeManager
2569 DataNode
[hadoop@weekend110 ~] jps
2473 NameNode
9650 Jps
9482 MRAppMaster
2747 SecondaryNameNode
2891 ResourceManager
9386 RunJar
2992 NodeManager
2569 DataNode
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
9665 YarnChild
2747 SecondaryNameNode
9681 YarnChild
9696 Jps
2891 ResourceManager
9386 RunJar
2992 NodeManager
2569 DataNode
9704 YarnChild
[hadoop@weekend110 ~] jps
2473 NameNode
9772 Jps
9482 MRAppMaster
9665 YarnChild
2747 SecondaryNameNode
9681 YarnChild
9770 YarnChild
9751 YarnChild
2891 ResourceManager
9386 RunJar
2992 NodeManager
9730 YarnChild
2569 DataNode
9704 YarnChild
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
9817 Jps
9665 -- process information unavailable
2747 SecondaryNameNode
9681 YarnChild
9770 YarnChild
9751 YarnChild
2891 ResourceManager
9386 RunJar
2992 NodeManager
9730 YarnChild
2569 DataNode
9704 YarnChild
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
2747 SecondaryNameNode
9681 YarnChild
9872 Jps
9770 YarnChild
9751 YarnChild
2891 ResourceManager
9386 RunJar
2992 NodeManager
9730 YarnChild
2569 DataNode
9704 YarnChild
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
9921 Jps
2747 SecondaryNameNode
9770 YarnChild
9751 YarnChild
2891 ResourceManager
9386 RunJar
2992 NodeManager
9730 YarnChild
2569 DataNode
9704 YarnChild
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
2747 SecondaryNameNode
9770 YarnChild
9751 -- process information unavailable
2891 ResourceManager
9386 RunJar
10021 Jps
2992 NodeManager
2569 DataNode
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
2747 SecondaryNameNode
10079 Jps
2891 ResourceManager
9386 RunJar
2992 NodeManager
2569 DataNode
[hadoop@weekend110 ~] jps
10090 Jps
2473 NameNode
9482 MRAppMaster
2747 SecondaryNameNode
2891 ResourceManager
2992 NodeManager
2569 DataNode
[hadoop@weekend110 ~] jps
2473 NameNode
9482 MRAppMaster
2747 SecondaryNameNode
10099 Jps
2891 ResourceManager
2992 NodeManager
2569 DataNode

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原文地址：https://www.cnblogs.com/DarrenChan/p/6464259.html