win8下使用eclipse进行hadoop2.6.2开发

最近在win平台下使用eclipse Mars做在远程linux上的hadoop2.6开发，出现很多问题，让人心力交瘁，在经过不懈努力后，终于解决了，让人欢欣雀跃。

1、安装JDK

在做hadoop2.6最好使用jdk7版本的，下载后安装。

2、下载eclipse

去http://www.eclipse.org/downloads/ 下载你需要的版本，我们这里下载的是win64位版。直接解压到目录中。进行简单设置，根据你的开发需要，选择jdk的版本

3、安装Hadoop2.6.0-eclipse-plugin

去https://github.com/winghc/hadoop2x-eclipse-plugin，在下载zip包后，在release目录中，有hadoop-eclipse-plugin-2.6.0.jar可以直接使用，不用在行编译。如使用其他版本，请参考其他文档。直接将hadoop-eclipse-plugin-2.6.0.jar复制到eclipse的plugins目录中即可。

4、安装Hadoop windows插件

包括hadoop.dll、winutils.exe。下载地址：https://github.com/srccodes/hadoop-common-2.2.0-bin

下载解压后，还需要配置环境变量，HADOOP_HOME = 解压目录，Path后增加 %HADOOP_HOME%\bin;

5、在eclipse中设置hadoop开发插件

打开eclipse，设置好工作区域后，点击

选择下图中红色标记，

在eclipse的工作区间中，左上角和下方会出现图中标记，如果出现，则说明前几步你都正确了。接下来对插件进行设置

6、设置hadoop插件

在eclipse菜单中选择，window - preferences，打开设置菜单

这里所用的hadoop版本需要和你linux上安装的hadoop版本一致，开发的时候插件会在这个目录中获取需要的开发包。设置完成后保存。

注：需要用二进制包，不用修改配置文件

设置完成后，就可以在eclipse的右上角看到你的hadoop的目录结构了。

7、上面只是点毛毛雨，下面才真正开始重点了，如何进行开发，我们使用hadoop的wordcount来做测试。

创建mr项目

设置项目名称

创建类

设置类属性

创建完成后，将hadoop-2.6.2-src\hadoop-mapreduce-project\hadoop-mapreduce-examples\src\main\java\org\apache\hadoop\examples目录下的WordCount.java文件内容，copy到刚创建的文件中。

8、接下来创建配置环境

在项目中，再创建一个Source Folder，名字叫resources，把你集群里的hadoop配置文件（etc/hadoop）拷贝到这个目录中，包括log4j.properties、core-site.xml、hdfs-site.xml、mapred-site.xml、yarn-site.xml。这几个配置文件除log4j.properties外，其他的因个人需求不一样而不同，但必须包括以下内容。

core-site.xml

<configuration>
      <property>
          <name>fs.defaultFS</name>
          <value>hdfs://192.168.114.128:9000</value>
    </property>
    <property>
        <name>hadoop.tmp.dir</name>
        <value>/home/zkpk/hadoop_data/tmp</value>
        <description>Abase for other temporary directories.</description>
    </property>
    <property>
        <name>fs.default.name</name>
        <value>hdfs://192.168.114.128:9000</value>
    </property>
</configuration>

hdfs-site.xml

<configuration>
    <property>
        <name>dfs.replication</name>
        <value>1</value>
    </property>
    <property>
        <name>dfs.namenode.name.dir</name>
        <value>/home/zkpk/hadoop_data/dfs/name</value>
    </property>
    <property>
        <name>dfs.datanode.data.dir</name>
        <value>/home/zkpk/hadoop_data/dfs/data</value>
    </property>
</configuration>

mapred-site.xml

<configuration>
    <property>
        <name>mapreduce.framework.name</name>
        <value>yarn</value>
      <description>远程开发必须</description>
    </property>
    <property>
        <name>mapred.remote.os</name>
        <value>Linux</value>
        <description>远程开发必须</description>
    </property>
    <property>
        <name>mapreduce.app-submission.cross-platform</name>
        <value>true</value>
        <description>远程开发必须</description>
    </property>
    <property>
        <name>mapreduce.application.classpath</name>
        <value>
            /home/zkpk/hadoop-2.6.2/etc/hadoop,
            /home/zkpk/hadoop-2.6.2/share/hadoop/common/*,
            /home/zkpk/hadoop-2.6.2/share/hadoop/common/lib/*,
            /home/zkpk/hadoop-2.6.2/share/hadoop/hdfs/*,
            /home/zkpk/hadoop-2.6.2/share/hadoop/hdfs/lib/*,
            /home/zkpk/hadoop-2.6.2/share/hadoop/mapreduce/*,
            /home/zkpk/hadoop-2.6.2/share/hadoop/mapreduce/lib/*,
            /home/zkpk/hadoop-2.6.2/share/hadoop/yarn/*,
            /home/zkpk/hadoop-2.6.2/share/hadoop/yarn/lib/*
        </value>
        <description>远程开发必须，制定远程目录上</description>
    </property>
    <property>
        <name>mapreduce.jobhistory.address</name>
        <value>192.168.114.128:10020</value>
    </property>
    <property>
        <name>mapreduce.jobhistory.webapp.address</name>
        <value>192.168.114.128:19888</value>
    </property>
    <property>
        <name>mapreduce.framework.name</name>
        <value>yarn</value>
        <description>远程开发必须</description>
    </property>
    <property>
        <name>mapred.job.tracker</name>
        <value>192.168.114.128:9001</value>
        <description>远程开发必须</description>
    </property>
</configuration>

yarn-site.xml

<configuration>
<property>
    <name>yarn.nodemanager.aux-services</name>
    <value>mapreduce_shuffle</value>
    <description>远程开发必须</description>
  </property>
    <property>
        <name>yarn.resourcemanager.address</name>
        <value>192.168.114.128:8032</value>
    </property>
</configuration>

以上完成后，即完成开发环境配置，接下来试试运行是否成功。

完成后，直接点击运行即可

看结果，如下就恭喜你成功了

15/12/18 09:14:13 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
15/12/18 09:14:13 INFO client.RMProxy: Connecting to ResourceManager at /192.168.114.128:8032
15/12/18 09:14:14 WARN mapreduce.JobResourceUploader: No job jar file set.  User classes may not be found. See Job or Job#setJar(String).
15/12/18 09:14:14 INFO input.FileInputFormat: Total input paths to process : 2
15/12/18 09:14:14 INFO mapreduce.JobSubmitter: number of splits:2
15/12/18 09:14:14 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1450342418109_0004
15/12/18 09:14:14 INFO mapred.YARNRunner: Job jar is not present. Not adding any jar to the list of resources.
15/12/18 09:14:14 INFO impl.YarnClientImpl: Submitted application application_1450342418109_0004
15/12/18 09:14:14 INFO mapreduce.Job: The url to track the job: http://master:8088/proxy/application_1450342418109_0004/
15/12/18 09:14:14 INFO mapreduce.Job: Running job: job_1450342418109_0004
15/12/18 09:14:21 INFO mapreduce.Job: Job job_1450342418109_0004 running in uber mode : false
15/12/18 09:14:21 INFO mapreduce.Job:  map 0% reduce 0%
15/12/18 09:14:31 INFO mapreduce.Job:  map 100% reduce 0%
15/12/18 09:14:39 INFO mapreduce.Job:  map 100% reduce 100%
15/12/18 09:14:40 INFO mapreduce.Job: Job job_1450342418109_0004 completed successfully
15/12/18 09:14:40 INFO mapreduce.Job: Counters: 49
	File System Counters
		FILE: Number of bytes read=79
		FILE: Number of bytes written=320590
		FILE: Number of read operations=0
		FILE: Number of large read operations=0
		FILE: Number of write operations=0
		HDFS: Number of bytes read=268
		HDFS: Number of bytes written=41
		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)=16220
		Total time spent by all reduces in occupied slots (ms)=4519
		Total time spent by all map tasks (ms)=16220
		Total time spent by all reduce tasks (ms)=4519
		Total vcore-seconds taken by all map tasks=16220
		Total vcore-seconds taken by all reduce tasks=4519
		Total megabyte-seconds taken by all map tasks=16609280
		Total megabyte-seconds taken by all reduce tasks=4627456
	Map-Reduce Framework
		Map input records=2
		Map output records=8
		Map output bytes=82
		Map output materialized bytes=85
		Input split bytes=218
		Combine input records=8
		Combine output records=6
		Reduce input groups=5
		Reduce shuffle bytes=85
		Reduce input records=6
		Reduce output records=5
		Spilled Records=12
		Shuffled Maps =2
		Failed Shuffles=0
		Merged Map outputs=2
		GC time elapsed (ms)=385
		CPU time spent (ms)=1660
		Physical memory (bytes) snapshot=460673024
		Virtual memory (bytes) snapshot=6179151872
		Total committed heap usage (bytes)=259063808
	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=50
	File Output Format Counters
		Bytes Written=41

错误解说：

1、WARN mapred.JobClient: No job jar file set.  User classes may not be found. See JobConf(Class) or JobConf#setJar(String).

INFO mapreduce.Job: Task Id : attempt_1450852806248_0029_m_000000_0, Status : FAILED
Error: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class org.apache.hadoop.mr.WordCount$TokenizerMapper not found

是由于没有jar上传到集群，所以mr的时候回出现找不到类的情况，需要再程序中增加以下语句

在mian函数的Configuration conf = new Configuration();后增加conf.set("mapred.jar", jar打包所在的地址);

例：conf.set("mapred.jar", "E:\\workspace\\WordCountTest\\bin\\org\\apache\\hadoop\\mr\\WordCountTest.jar");