MapReduce Demo

功能：统计公司员工一个月内手机上网上行流量、下行流量及总流量。 

测试数据如下：

13612345678     6000    1000

13612345678     2000    3000

13812345678     2000    100

13812345678     1500    300

13512345678     9000    200

13512345678     500     200

13112345678     1000    200

13112345678     800     200

代码：

   程序入口类：DataCount  

package cn.terry.mr;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.mapreduce.Job;

import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;

import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import com.sun.jersey.core.impl.provider.entity.XMLJAXBElementProvider.Text;

public class DataCount {

  

public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {

Configuration conf=new Configuration();

Job job=Job.getInstance(conf);

         job.setJarByClass(DataCount.class);

         job.setMapperClass(MRMap.class);  

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

  

         job.setReducerClass(MRReduce.class);

         job.setMapOutputKeyClass(Text.class);

         job.setMapOutputValueClass(DataBean.class);    

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

         job.waitForCompletion(true);

}         

}  

数据实体类：  DataBean.java

package cn.terry.mr; 

import java.io.DataInput;

import java.io.DataOutput;

import java.io.IOException;

import org.apache.hadoop.io.Writable;

public class DataBean implements Writable {

private String telNo;

private Long upPayLoad;

private Long downPayLoad;

private Long totalPayLoad;

public String getTelNo() {

return telNo;

}

public void setTelNo(String telNo) {

this.telNo = telNo;

}

public Long getUpPayLoad() {

return upPayLoad;

}

public void setUpPayLoad(Long upPayLoad) {

this.upPayLoad = upPayLoad;

}

public Long getDownPayLoad() {

return downPayLoad;

}

public void setDownPayLoad(Long downPayLoad) {

this.downPayLoad = downPayLoad;

}

public Long getTotalPayLoad() {

return totalPayLoad;

}

public void setTotalPayLoad(Long totalPayLoad) {

this.totalPayLoad = totalPayLoad;

}  

public DataBean() {  

}

public DataBean(String telNo, Long upPayLoad, Long downPayLoad) {

 

this.telNo = telNo;

this.upPayLoad = upPayLoad;

this.downPayLoad = downPayLoad;

this.totalPayLoad=this.upPayLoad+this.downPayLoad;

}

//serialize

@Override

public void write(DataOutput out) throws IOException {

// TODO Auto-generated method stub

    out.writeUTF(telNo);

    out.writeLong(upPayLoad);

    out.writeLong(downPayLoad);

    out.writeLong(totalPayLoad);

}

//deserrialize

@Override

public void readFields(DataInput in) throws IOException {

// TODO Auto-generated method stub

this.telNo=in.readUTF();

this.upPayLoad=in.readLong();

this.downPayLoad=in.readLong();

this.totalPayLoad=in.readLong();

}

@Override

public String toString() {

// TODO Auto-generated method stub

return  this.upPayLoad+" "+ this.downPayLoad+" " + this.totalPayLoad;

}

} 

Map类：MRMap.java  

package cn.terry.mr;

import java.io.IOException;

import org.apache.hadoop.mapreduce.Mapper;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Mapper;

public  class MRMap extends Mapper<LongWritable,Text,Text,DataBean> {

@Override

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

String line=value.toString();

String[] fields=line.split(" ");

String telNo=fields[0];

Long up=Long.parseLong(fields[1]);

Long down= Long.parseLong(fields[2]);

DataBean bean=new DataBean(telNo,up,down);

context.write(new Text(telNo), bean);

}   

} 

Reduce类：MRReduce.java

package cn.terry.mr;

import java.io.IOException;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Reducer;

public class MRReduce extends Reducer<Text,DataBean,Text,DataBean> {

@Override

protected void reduce(Text key, Iterable<DataBean> v2,  Context context) throws IOException, InterruptedException {

long up_sum=0;

long down_sum=0;

for(DataBean bean :v2)

{

up_sum+=bean.getUpPayLoad();

down_sum+=bean.getDownPayLoad();

}

DataBean bean=new DataBean("",up_sum,down_sum);

context.write(key, bean);

}

} 

 运行：

[root@master bin]# hadoop jar /home/hadoop/mpCount.jar cn.terry.mr.DataCount /data.txt /mrOut

17/11/08 11:34:25 INFO client.RMProxy: Connecting to ResourceManager at master/1:80 32

17/11/08 11:34:27 WARN mapreduce.JobResourceUploader: Hadoop command-line option parsing not p erformed. Implement the Tool interface and execute your application with ToolRunner to remedy this.

17/11/08 11:34:27 INFO input.FileInputFormat: Total input paths to process : 1

17/11/08 11:34:28 INFO mapreduce.JobSubmitter: number of splits:1

17/11/08 11:34:28 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1509957441313_00 02

17/11/08 11:34:29 INFO impl.YarnClientImpl: Submitted application application_1509957441313_00 02

17/11/08 11:34:29 INFO mapreduce.Job: The url to track the job: http://master:8088/proxy/appli cation_1509957441313_0002/

17/11/08 11:34:29 INFO mapreduce.Job: Running job: job_1509957441313_0002

17/11/08 11:34:46 INFO mapreduce.Job: Job job_1509957441313_0002 running in uber mode : false

17/11/08 11:34:46 INFO mapreduce.Job: map 0% reduce 0%

17/11/08 11:34:55 INFO mapreduce.Job: Task Id : attempt_1509957441313_0002_m_000000_0, Status : FAILED Error: java.io.IOException: Initialization of all the collectors failed. Error in last collect or was :class com.sun.jersey.core.impl.provider.entity.XMLJAXBElementProvider$Text at org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:415) at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:81) at org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:698) at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:770) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341) at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:164) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1746 

以上错误可看出hadoop引用的Text包出错，需要将DataCount类中Text的包引用改为 import org.apache.hadoop.io.Text;

 再次运行：  

[root@master bin]# hadoop jar /home/hadoop/mpCount.jar cn.terry.mr.DataCount /data3.txt /MROut4 

17/11/08 16:23:45 INFO client.RMProxy: Connecting to ResourceManager at master/x.x.x.x:8032

17/11/08 16:23:46 WARN mapreduce.JobResourceUploader: Hadoop command-line option parsing not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.

17/11/08 16:23:47 INFO input.FileInputFormat: Total input paths to process : 1

17/11/08 16:23:47 INFO mapreduce.JobSubmitter: number of splits:1

17/11/08 16:23:47 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1509957441313_0008

17/11/08 16:23:48 INFO impl.YarnClientImpl: Submitted application application_1509957441313_0008

17/11/08 16:23:48 INFO mapreduce.Job: The url to track the job: http://master:8088/proxy/application_1509957441313_0008/

17/11/08 16:23:48 INFO mapreduce.Job: Running job: job_1509957441313_0008

17/11/08 16:24:02 INFO mapreduce.Job: Job job_1509957441313_0008 running in uber mode : false

17/11/08 16:24:02 INFO mapreduce.Job:  map 0% reduce 0%

17/11/08 16:24:14 INFO mapreduce.Job:  map 100% reduce 0%

17/11/08 16:24:25 INFO mapreduce.Job:  map 100% reduce 100%

17/11/08 16:24:26 INFO mapreduce.Job: Job job_1509957441313_0008 completed successfully 

查看结果：

[root@master bin]# hdfs dfs -ls /MROut4

Found 2 items

-rw-r--r--   2 root supergroup          0 2017-11-08 16:24 /MROut4/_SUCCESS

-rw-r--r--   2 root supergroup        106 2017-11-08 16:24 /MROut4/part-r-00000

[root@master bin]# hdfs dfs -cat /MROut4/part-r-00000

13112345678     1800    400     2200

13512345678     9500    400     9900

13612345678     8000    4000    12000

13812345678     3500    400     3900

 由于我的chrome和IE版本无法兼容cnblogs的插入code和picture功能，抱歉没能将代码及结果以友好的方式呈现。