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编写简单的Mapreduce程序并部署在Hadoop2.2.0上运行

程序员文章站 2022-05-18 16:41:08
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经过几天的折腾,终于配置好了 Hadoop 2.2.0(如何配置在Linux平台部署 Hadoop 请参见本博客《在Fedora上部署Hadoop2.2.0伪分布式平台》),今天主要来说说怎么在Hadoop2.2.0伪分布式上面运行我们写好的 Mapreduce 程序。先给出这个程序所依赖的Maven包: 01 0

经过几天的折腾,终于配置好了Hadoop2.2.0(如何配置在Linux平台部署Hadoop请参见本博客《在Fedora上部署Hadoop2.2.0伪分布式平台》),今天主要来说说怎么在Hadoop2.2.0伪分布式上面运行我们写好的Mapreduce程序。先给出这个程序所依赖的Maven包:

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org.apache.hadoop

hadoop-mapreduce-client-core

2.1.1-beta

org.apache.hadoop

hadoop-common

2.1.1-beta

org.apache.hadoop

hadoop-mapreduce-client-common

2.1.1-beta

org.apache.hadoop

hadoop-mapreduce-client-jobclient

2.1.1-beta

好了,现在给出程序,代码如下:

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package com.wyp.hadoop;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapred.*;

import java.io.IOException;

/**

* User: wyp

* Date: 13-10-25

* Time: 下午3:26

* Email:wyphao.2007@163.com

*/

public class MaxTemperatureMapper extends MapReduceBase

implements Mapper

Text,IntWritable>{

private static final int MISSING = 9999;

@Override

public void map(LongWritable key, Text value,

OutputCollector output,

Reporter reporter) throws IOException {

String line = value.toString();

String year = line.substring(15, 19);

int airTemperature;

if(line.charAt(87) == '+'){

airTemperature = Integer.parseInt(line.substring(88, 92));

}else{

airTemperature = Integer.parseInt(line.substring(87, 92));

}

String quality = line.substring(92, 93);

if(airTemperature != MISSING && quality.matches("[01459]")){

output.collect(new Text(year), new IntWritable(airTemperature));

}

}

}

package com.wyp.hadoop;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapred.MapReduceBase;

import org.apache.hadoop.mapred.OutputCollector;

import org.apache.hadoop.mapred.Reducer;

import org.apache.hadoop.mapred.Reporter;

import java.io.IOException;

import java.util.Iterator;

/**

* User: wyp

* Date: 13-10-25

* Time: 下午3:36

* Email:wyphao.2007@163.com

*/

public class MaxTemperatureReducer extends MapReduceBase

implements Reducer

Text, IntWritable> {

@Override

public void reduce(Text key, Iterator values,

OutputCollector output,

Reporter reporter) throws IOException {

int maxValue = Integer.MIN_VALUE;

while (values.hasNext()){

maxValue = Math.max(maxValue, values.next().get());

}

output.collect(key, new IntWritable(maxValue));

}

}

package com.wyp.hadoop;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapred.FileInputFormat;

import org.apache.hadoop.mapred.FileOutputFormat;

import org.apache.hadoop.mapred.JobClient;

import org.apache.hadoop.mapred.JobConf;

import java.io.IOException;

/**

* User: wyp

* Date: 13-10-25

* Time: 下午3:40

* Email:wyphao.2007@163.com

*/

public class MaxTemperature {

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

if(args.length != 2){

System.err.println("Error!");

System.exit(1);

}

JobConf conf = new JobConf(MaxTemperature.class);

conf.setJobName("Max Temperature");

FileInputFormat.addInputPath(conf, new Path(args[0]));

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

conf.setMapperClass(MaxTemperatureMapper.class);

conf.setReducerClass(MaxTemperatureReducer.class);

conf.setOutputKeyClass(Text.class);

conf.setOutputValueClass(IntWritable.class);

JobClient.runJob(conf);

}

}

  将上面的程序编译和打包成jar文件,然后开始在Hadoop2.2.0(本文假定用户都部署好了Hadoop2.2.0)上面部署了。下面主要讲讲如何去部署:
  首先,启动Hadoop2.2.0,命令如下:

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[wyp@wyp hadoop]$ sbin/start-dfs.sh

[wyp@wyp hadoop]$ sbin/start-yarn.sh

  如果你想看看Hadoop2.2.0是否运行成功,运行下面的命令去查看

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[wyp@wyp hadoop]$ jps

9582 Main

9684 RemoteMavenServer

16082 Jps

7011 DataNode

7412 ResourceManager

7528 NodeManager

7222 SecondaryNameNode

6832 NameNode

  其中jps是jdk自带的一个命令,在jdk/bin目录下。如果你电脑上面出现了以上的几个进程(NameNode、SecondaryNameNode、NodeManager、ResourceManager、DataNode这五个进程必须出现!)说明你的Hadoop服务器启动成功了!现在来运行上面打包好的jar文件(这里为Hadoop.jar,其中/home/wyp/IdeaProjects/Hadoop/out/artifacts/Hadoop_jar/Hadoop.jar是它的绝对路径,不知道绝对路径是什么?那你好好去学学吧!),运行下面的命令:

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[wyp@wyp Hadoop_jar]$ /home/wyp/Downloads/hadoop/bin/hadoop jar \

/home/wyp/IdeaProjects/Hadoop/out/artifacts/Hadoop_jar/Hadoop.jar \

com/wyp/hadoop/MaxTemperature \

/user/wyp/data.txt \

/user/wyp/result

  (上面是一条命令,由于太长了,所以我分行写,在实际情况中,请写一行!)其中,/home/wyp/Downloads/hadoop/bin/hadoop是hadoop的绝对路径,如果你在环境变量中配置好hadoop命令的路径就不需要这样写;com/wyp/hadoop/MaxTemperature是上面程序的main函数的入口;/user/wyp/data.txt是Hadoop文件系统(HDFS)中的绝对路径(注意:这里不是你Linux系统中的绝对路径!),为需要分析文件的路径(也就是input);/user/wyp/result是分析结果输出的绝对路径(注意:这里不是你Linux系统中的绝对路径!而是HDFS上面的路径!而且/user/wyp/result一定不能存在,否则会抛出异常!这是Hadoop的保护机制,你总不想你以前运行好几天的程序突然被你不小心给覆盖掉了吧?所以,如果/user/wyp/result存在,程序会抛出异常,很不错啊)。好了。输入上面的命令,应该会得到下面类似的输出:

13/10/28 15:20:44 INFO client.RMProxy: Connecting to ResourceManager at /0.0.0.0:8032
13/10/28 15:20:44 INFO client.RMProxy: Connecting to ResourceManager at /0.0.0.0:8032
13/10/28 15:20:45 WARN mapreduce.JobSubmitter: Hadoop command-line option parsing not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.
13/10/28 15:20:45 WARN mapreduce.JobSubmitter: No job jar file set.  User classes may not be found. See Job or Job#setJar(String).
13/10/28 15:20:45 INFO mapred.FileInputFormat: Total input paths to process : 1
13/10/28 15:20:46 INFO mapreduce.JobSubmitter: number of splits:2
13/10/28 15:20:46 INFO Configuration.deprecation: user.name is deprecated. Instead, use mapreduce.job.user.name
13/10/28 15:20:46 INFO Configuration.deprecation: mapred.output.value.class is deprecated. Instead, use mapreduce.job.output.value.class
13/10/28 15:20:46 INFO Configuration.deprecation: mapred.job.name is deprecated. Instead, use mapreduce.job.name
13/10/28 15:20:46 INFO Configuration.deprecation: mapred.input.dir is deprecated. Instead, use mapreduce.input.fileinputformat.inputdir
13/10/28 15:20:46 INFO Configuration.deprecation: mapred.output.dir is deprecated. Instead, use mapreduce.output.fileoutputformat.outputdir
13/10/28 15:20:46 INFO Configuration.deprecation: mapred.map.tasks is deprecated. Instead, use mapreduce.job.maps
13/10/28 15:20:46 INFO Configuration.deprecation: mapred.output.key.class is deprecated. Instead, use mapreduce.job.output.key.class
13/10/28 15:20:46 INFO Configuration.deprecation: mapred.working.dir is deprecated. Instead, use mapreduce.job.working.dir
13/10/28 15:20:46 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1382942307976_0008
13/10/28 15:20:47 INFO mapred.YARNRunner: Job jar is not present. Not adding any jar to the list of resources.
13/10/28 15:20:49 INFO impl.YarnClientImpl: Submitted application application_1382942307976_0008 to ResourceManager at /0.0.0.0:8032
13/10/28 15:20:49 INFO mapreduce.Job: The url to track the job: http://wyp:8088/proxy/application_1382942307976_0008/
13/10/28 15:20:49 INFO mapreduce.Job: Running job: job_1382942307976_0008
13/10/28 15:20:59 INFO mapreduce.Job: Job job_1382942307976_0008 running in uber mode : false
13/10/28 15:20:59 INFO mapreduce.Job:  map 0% reduce 0%
13/10/28 15:21:35 INFO mapreduce.Job:  map 100% reduce 0%
13/10/28 15:21:38 INFO mapreduce.Job:  map 0% reduce 0%
13/10/28 15:21:38 INFO mapreduce.Job: Task Id : attempt_1382942307976_0008_m_000000_0, Status : FAILED
Error: java.lang.RuntimeException: Error in configuring object
    at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
    at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:75)
    at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:133)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:425)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
    at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:162)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
    at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:157)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:106)
    ... 9 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class com.wyp.hadoop.MaxTemperatureMapper1 not found
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1752)
    at org.apache.hadoop.mapred.JobConf.getMapperClass(JobConf.java:1058)
    at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:38)
    ... 14 more
Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class com.wyp.hadoop.MaxTemperatureMapper1 not found
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1720)
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1744)
    ... 16 more
Caused by: java.lang.ClassNotFoundException: Class com.wyp.hadoop.MaxTemperatureMapper1 not found
    at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:1626)
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1718)
    ... 17 more
 
Container killed by the ApplicationMaster.
Container killed on request. Exit code is 143

程序居然抛出异常(ClassNotFoundException)!这是什么回事?其实我也不太明白!!

  在网上Google了一下,找到别人的观点:
  经个人总结,这通常是由于以下几种原因造成的:
(1)你编写了一个java lib,封装成了jar,然后再写了一个Hadoop程序,调用这个jar完成mapper和reducer的编写
(2)你编写了一个Hadoop程序,期间调用了一个第三方java lib。
之后,你将自己的jar包或者第三方java包分发到各个TaskTracker的HADOOP_HOME目录下,运行你的JAVA程序,报了以上错误。

  那怎么解决呢?一个笨重的方法是,在运行Hadoop作业的时候,先运行下面的命令:

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[wyp@wyp Hadoop_jar]$ export \

HADOOP_CLASSPATH=/home/wyp/IdeaProjects/Hadoop/out/artifacts/Hadoop_jar/

  其中,/home/wyp/IdeaProjects/Hadoop/out/artifacts/Hadoop_jar/是上面Hadoop.jar文件所在的目录。好了,现在再运行一下Hadoop作业命令:

[wyp@wyp Hadoop_jar]$ hadoop jar /home/wyp/IdeaProjects/Hadoop/out/artifacts/Hadoop_jar/Hadoop.jar  com/wyp/hadoop/MaxTemperature /user/wyp/data.txt /user/wyp/result
13/10/28 15:34:16 INFO client.RMProxy: Connecting to ResourceManager at /0.0.0.0:8032
13/10/28 15:34:16 INFO client.RMProxy: Connecting to ResourceManager at /0.0.0.0:8032
13/10/28 15:34:17 WARN mapreduce.JobSubmitter: Hadoop command-line option parsing not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.
13/10/28 15:34:17 INFO mapred.FileInputFormat: Total input paths to process : 1
13/10/28 15:34:17 INFO mapreduce.JobSubmitter: number of splits:2
13/10/28 15:34:17 INFO Configuration.deprecation: user.name is deprecated. Instead, use mapreduce.job.user.name
13/10/28 15:34:17 INFO Configuration.deprecation: mapred.jar is deprecated. Instead, use mapreduce.job.jar
13/10/28 15:34:17 INFO Configuration.deprecation: mapred.output.value.class is deprecated. Instead, use mapreduce.job.output.value.class
13/10/28 15:34:17 INFO Configuration.deprecation: mapred.job.name is deprecated. Instead, use mapreduce.job.name
13/10/28 15:34:17 INFO Configuration.deprecation: mapred.input.dir is deprecated. Instead, use mapreduce.input.fileinputformat.inputdir
13/10/28 15:34:17 INFO Configuration.deprecation: mapred.output.dir is deprecated. Instead, use mapreduce.output.fileoutputformat.outputdir
13/10/28 15:34:17 INFO Configuration.deprecation: mapred.map.tasks is deprecated. Instead, use mapreduce.job.maps
13/10/28 15:34:17 INFO Configuration.deprecation: mapred.output.key.class is deprecated. Instead, use mapreduce.job.output.key.class
13/10/28 15:34:17 INFO Configuration.deprecation: mapred.working.dir is deprecated. Instead, use mapreduce.job.working.dir
13/10/28 15:34:18 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1382942307976_0009
13/10/28 15:34:18 INFO impl.YarnClientImpl: Submitted application application_1382942307976_0009 to ResourceManager at /0.0.0.0:8032
13/10/28 15:34:18 INFO mapreduce.Job: The url to track the job: http://wyp:8088/proxy/application_1382942307976_0009/
13/10/28 15:34:18 INFO mapreduce.Job: Running job: job_1382942307976_0009
13/10/28 15:34:26 INFO mapreduce.Job: Job job_1382942307976_0009 running in uber mode : false
13/10/28 15:34:26 INFO mapreduce.Job:  map 0% reduce 0%
13/10/28 15:34:41 INFO mapreduce.Job:  map 50% reduce 0%
13/10/28 15:34:53 INFO mapreduce.Job:  map 100% reduce 0%
13/10/28 15:35:17 INFO mapreduce.Job:  map 100% reduce 100%
13/10/28 15:35:18 INFO mapreduce.Job: Job job_1382942307976_0009 completed successfully
13/10/28 15:35:18 INFO mapreduce.Job: Counters: 43
    File System Counters
        FILE: Number of bytes read=144425
        FILE: Number of bytes written=524725
        FILE: Number of read operations=0
        FILE: Number of large read operations=0
        FILE: Number of write operations=0
        HDFS: Number of bytes read=1777598
        HDFS: Number of bytes written=18
        HDFS: Number of read operations=9
        HDFS: Number of large read operations=0
        HDFS: Number of write operations=2
    Job Counters 
        Launched map tasks=2
        Launched reduce tasks=1
        Data-local map tasks=2
        Total time spent by all maps in occupied slots (ms)=38057
        Total time spent by all reduces in occupied slots (ms)=24800
    Map-Reduce Framework
        Map input records=13130
        Map output records=13129
        Map output bytes=118161
        Map output materialized bytes=144431
        Input split bytes=182
        Combine input records=0
        Combine output records=0
        Reduce input groups=2
        Reduce shuffle bytes=144431
        Reduce input records=13129
        Reduce output records=2
        Spilled Records=26258
        Shuffled Maps =2
        Failed Shuffles=0
        Merged Map outputs=2
        GC time elapsed (ms)=321
        CPU time spent (ms)=5110
        Physical memory (bytes) snapshot=552824832
        Virtual memory (bytes) snapshot=1228738560
        Total committed heap usage (bytes)=459800576
    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=1777416
    File Output Format Counters 
        Bytes Written=18

到这里,程序就成功运行了!很高兴吧?那么怎么查看刚刚程序运行的结果呢?很简单,运行下面命令:

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[wyp@wyp Hadoop_jar]$ hadoop fs -ls /user/wyp

Found 2 items

-rw-r--r-- 1 wyp supergroup 1777168 2013-10-25 17:44 /user/wyp/data.txt

drwxr-xr-x - wyp supergroup 0 2013-10-28 15:35 /user/wyp/result

[wyp@wyp Hadoop_jar]$ hadoop fs -ls /user/wyp/result

Found 2 items

-rw-r--r-- 1 wyp supergroup 0 2013-10-28 15:35 /user/wyp/result/_SUCCESS

-rw-r--r-- 1 wyp supergroup 18 2013-10-28 15:35 /user/wyp/result/part-00000

[wyp@wyp Hadoop_jar]$ hadoop fs -cat /user/wyp/result/part-00000

1901 317

1902 244

  到此,你自己写好的一个Mapreduce程序终于成功运行了!
  附程序测试的数据的下载地址:http://pan.baidu.com/s/1iSacM

过往记忆(http://www.iteblog.com/)
编写简单的Mapreduce程序并部署在Hadoop2.2.0上运行(http://www.iteblog.com/archives/789)