Hadoop2.5.2 Eclipse插件安装及相关问题

资源下载 1.下载Hadoop-2.5.2.tar.gzhttp://mirror.bit.edu.cn/apache/hadoop/common/hadoop-2.5.2/hadoop-2.5.2.tar.gz 2.下载hadoop2.5.2-eclipse-pluginhttp://download.csdn.net/detail/lzm1340458776/8519515 3.下载hadoop-common-2.2.0-binhttps://git

资源下载

1.下载Hadoop-2.5.2.tar.gz http://mirror.bit.edu.cn/apache/hadoop/common/hadoop-2.5.2/hadoop-2.5.2.tar.gz

2.下载hadoop2.5.2-eclipse-plugin http://download.csdn.net/detail/lzm1340458776/8519515

3.下载hadoop-common-2.2.0-bin https://github.com/srccodes/hadoop-common-2.2.0-bin

开始安装

1.解压hadoop-2.5.2.tar.gz到win7下某个路径。

2.配置本地hadoop的环境

3.window-->Preferences--->Hadoop Map/Reduce 关联步骤1中解压的hadoop路径

4.Window--->show view选择Map/Reduce Locations

5.配置连接参数

注：Host可以填写IP地址，也可以填写对应的主机名(要在C盘hosts文件配置对应的主机名)，MapReduce的Port可以默认，HDFS的Port为core-site.xml文件中配置的端口。

6.查看文件系统

相关问题：

7.编写WordCount程序，运行可能会出现如下错误：

java.lang.NullPointerException
	at java.lang.ProcessBuilder.start(Unknown Source)
	at org.apache.hadoop.util.Shell.runCommand(Shell.java:482)
	at org.apache.hadoop.util.Shell.run(Shell.java:455)
	at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:702)
	at org.apache.hadoop.util.Shell.execCommand(Shell.java:791)
	at org.apache.hadoop.util.Shell.execCommand(Shell.java:774)
	at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:646)
	at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:434)
	at org.apache.hadoop.fs.FilterFileSystem.mkdirs(FilterFileSystem.java:281)
	at org.apache.hadoop.mapreduce.JobSubmissionFiles.getStagingDir(JobSubmissionFiles.java:125)
	at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:348)
	at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1285)
	at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1282)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Unknown Source)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1614)
	at org.apache.hadoop.mapreduce.Job.submit(Job.java:1282)
	at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1303)
	at com.lixue.mapreduce.chain.WordCountMapReduce.main(WordCountMapReduce.java:70)

出现这个问题的原因是window下缺少运行MR程序的工具。

解决方案：

解压hadoop-common-2.2.0-bin，将解压后的bin目录覆盖hadoop解压后目录中的bin文件夹。

此时运行MapReduce程序，又会发现控制台只输出了如下信息：

log4j:WARN No appenders could be found for logger (com.hp.hpl.jena.util.FileManager).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

解决方案：

把hadoop-2.5.2/etc/hadoop/log4j.properties文件拷贝到项目的src目录下。

再次运行MapReduce程序，又出现了一个问题：

java.lang.RuntimeException: java.lang.InstantiationException
	at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:131)
	at org.apache.hadoop.mapreduce.JobSubmitter.writeNewSplits(JobSubmitter.java:490)
	at org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:510)
	at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:394)
	at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1285)
	at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1282)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Unknown Source)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1614)
	at org.apache.hadoop.mapreduce.Job.submit(Job.java:1282)
	at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1303)
	at com.lixue.mapreduce.chain.WordCountMapReduce.main(WordCountMapReduce.java:72)
Caused by: java.lang.InstantiationException
	at sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(Unknown Source)
	at java.lang.reflect.Constructor.newInstance(Unknown Source)
	at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:129)
	... 11 more

解决方案：

把驱动类中的：

job.setInputFormatClass(FileInputFormat.class);

改成：

job.setInputFormatClass(TextInputFormat.class);