一、前言

环境：

系统：centos6.5
hadoop版本：Apache hadoop2.7.3（Windows和centos都是同一个）
eclipse版本：4.2.0（juno版本，windows）
ant版本：ant 1.7.1（windows）
java版本：1.8.0_05（windows）

我是在虚拟机中安装的系统，具体的安装和配置参考：Hadoop单机伪分布部署。

二、制作插件

1. 下载hadoop2x-eclipse-plugin-master.zip

在github下载：https://github.com/winghc/hadoop2x-eclipse-plugin。

2. 修改配置

原来的配置是编译2.4.1的，为了编译成2.7.3版本，首先需要改2个文件。

1) 修改hadoop2x-eclipse-plugin-master/src/contrib/eclipse-plugin/build.xml

在第82行找到 <target name="jar" depends="compile" unless="skip.contrib">标签，找到下面的子标签（在127行）：

<copy file="${hadoop.home}/share/hadoop/common/lib/htrace-core-${htrace.version}.jar"  todir="${build.dir}/lib" verbose="true"/>

删掉这行，然后在下面增加多三行信息：

<copy file="${hadoop.home}/share/hadoop/common/lib/htrace-core-${htrace.version}-incubating.jar"  todir="${build.dir}/lib" verbose="true"/>
<copy file="${hadoop.home}/share/hadoop/common/lib/servlet-api-${servlet-api.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
<copy file="${hadoop.home}/share/hadoop/common/lib/commons-io-${commons-io.version}.jar"  todir="${build.dir}/lib" verbose="true"/>

然后找到标签<attribute name="Bundle-ClassPath"，在下面的标签中，删除lib/htrace-core-${htrace.version}.jar这行，同样加多三行：

lib/servlet-api-${servlet-api.version}.jar,
lib/commons-io-${commons-io.version}.jar,
lib/htrace-core-${htrace.version}-incubating.jar"

修改完的文件：

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<!--
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
-->

<project default="jar" name="eclipse-plugin">

  <import file="../build-contrib.xml"/>

  <path id="eclipse-sdk-jars">
    <fileset dir="${eclipse.home}/plugins/">
      <include name="org.eclipse.ui*.jar"/>
      <include name="org.eclipse.jdt*.jar"/>
      <include name="org.eclipse.core*.jar"/>
      <include name="org.eclipse.equinox*.jar"/>
      <include name="org.eclipse.debug*.jar"/>
      <include name="org.eclipse.osgi*.jar"/>
      <include name="org.eclipse.swt*.jar"/>
      <include name="org.eclipse.jface*.jar"/>

      <include name="org.eclipse.team.cvs.ssh2*.jar"/>
      <include name="com.jcraft.jsch*.jar"/>
    </fileset>
  </path>

  <path id="hadoop-sdk-jars">
    <fileset dir="${hadoop.home}/share/hadoop/mapreduce">
      <include name="hadoop*.jar"/>
    </fileset>
    <fileset dir="${hadoop.home}/share/hadoop/hdfs">
      <include name="hadoop*.jar"/>
    </fileset>
    <fileset dir="${hadoop.home}/share/hadoop/common">
      <include name="hadoop*.jar"/>
    </fileset>
  </path>

  <!-- Override classpath to include Eclipse SDK jars -->
  <path id="classpath">
    <pathelement location="${build.classes}"/>
    <!--pathelement location="${hadoop.root}/build/classes"/-->
    <path refid="eclipse-sdk-jars"/>
    <path refid="hadoop-sdk-jars"/>
  </path>

  <!-- Skip building if eclipse.home is unset. -->
  <target name="check-contrib" unless="eclipse.home">
    <property name="skip.contrib" value="yes"/>
    <echo message="eclipse.home unset: skipping eclipse plugin"/>
  </target>

 <target name="compile" depends="init, ivy-retrieve-common" unless="skip.contrib">
    <echo message="contrib: ${name}"/>
    <javac
     encoding="${build.encoding}"
     srcdir="${src.dir}"
     includes="**/*.java"
     destdir="${build.classes}"
     debug="${javac.debug}"
     deprecation="${javac.deprecation}">
     <classpath refid="classpath"/>
    </javac>
  </target>

  <!-- Override jar target to specify manifest -->
  <target name="jar" depends="compile" unless="skip.contrib">
    <mkdir dir="${build.dir}/lib"/>
    <copy  todir="${build.dir}/lib/" verbose="true">
          <fileset dir="${hadoop.home}/share/hadoop/mapreduce">
           <include name="hadoop*.jar"/>
          </fileset>
    </copy>
    <copy  todir="${build.dir}/lib/" verbose="true">
          <fileset dir="${hadoop.home}/share/hadoop/common">
           <include name="hadoop*.jar"/>
          </fileset>
    </copy>
    <copy  todir="${build.dir}/lib/" verbose="true">
          <fileset dir="${hadoop.home}/share/hadoop/hdfs">
           <include name="hadoop*.jar"/>
          </fileset>
    </copy>
    <copy  todir="${build.dir}/lib/" verbose="true">
          <fileset dir="${hadoop.home}/share/hadoop/yarn">
           <include name="hadoop*.jar"/>
          </fileset>
    </copy>

    <copy  todir="${build.dir}/classes" verbose="true">
          <fileset dir="${root}/src/java">
           <include name="*.xml"/>
          </fileset>
    </copy>

    <copy file="${hadoop.home}/share/hadoop/common/lib/protobuf-java-${protobuf.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/log4j-${log4j.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/commons-cli-${commons-cli.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/commons-configuration-${commons-configuration.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/commons-lang-${commons-lang.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/commons-collections-${commons-collections.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/jackson-core-asl-${jackson.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/jackson-mapper-asl-${jackson.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/slf4j-log4j12-${slf4j-log4j12.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/slf4j-api-${slf4j-api.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/guava-${guava.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/hadoop-auth-${hadoop.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/commons-cli-${commons-cli.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/netty-${netty.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/htrace-core-${htrace.version}-incubating.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/servlet-api-${servlet-api.version}.jar"  todir="${build.dir}/lib" verbose="true"/>
    <copy file="${hadoop.home}/share/hadoop/common/lib/commons-io-${commons-io.version}.jar"  todir="${build.dir}/lib" verbose="true"/> 

    <jar
      jarfile="${build.dir}/hadoop-${name}-${hadoop.version}.jar"
      manifest="${root}/META-INF/MANIFEST.MF">
      <manifest>
   <attribute name="Bundle-ClassPath"
    value="classes/,
 lib/hadoop-mapreduce-client-core-${hadoop.version}.jar,
 lib/hadoop-mapreduce-client-common-${hadoop.version}.jar,
 lib/hadoop-mapreduce-client-jobclient-${hadoop.version}.jar,
 lib/hadoop-auth-${hadoop.version}.jar,
 lib/hadoop-common-${hadoop.version}.jar,
 lib/hadoop-hdfs-${hadoop.version}.jar,
 lib/protobuf-java-${protobuf.version}.jar,
 lib/log4j-${log4j.version}.jar,
 lib/commons-cli-${commons-cli.version}.jar,
 lib/commons-configuration-${commons-configuration.version}.jar,
 lib/commons-httpclient-${commons-httpclient.version}.jar,
 lib/commons-lang-${commons-lang.version}.jar,
 lib/commons-collections-${commons-collections.version}.jar,
 lib/jackson-core-asl-${jackson.version}.jar,
 lib/jackson-mapper-asl-${jackson.version}.jar,
 lib/slf4j-log4j12-${slf4j-log4j12.version}.jar,
 lib/slf4j-api-${slf4j-api.version}.jar,
 lib/guava-${guava.version}.jar,
 lib/netty-${netty.version}.jar,
 lib/servlet-api-${servlet-api.version}.jar,
 lib/commons-io-${commons-io.version}.jar,
 lib/htrace-core-${htrace.version}-incubating.jar"/>
   </manifest>
      <fileset dir="${build.dir}" includes="classes/ lib/"/>
      <!--fileset dir="${build.dir}" includes="*.xml"/-->
      <fileset dir="${root}" includes="resources/ plugin.xml"/>
    </jar>
  </target>

</project>

2) 修改hadoop2x-eclipse-plugin-master/ivy/libraries.properties

#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

#This properties file lists the versions of the various artifacts used by hadoop and components.
#It drives ivy and the generation of a maven POM

# This is the version of hadoop we are generating
#hadoop.version=2.6.0    modify
hadoop.version=2.7.3
hadoop-gpl-compression.version=0.1.0

#These are the versions of our dependencies (in alphabetical order)
apacheant.version=1.7.1
ant-task.version=2.0.10

asm.version=3.2
aspectj.version=1.6.5
aspectj.version=1.6.11

checkstyle.version=4.2

commons-cli.version=1.2
commons-codec.version=1.4
#commons-collections.version=3.2.1    modify
commons-collections.version=3.2.2
commons-configuration.version=1.6
commons-daemon.version=1.0.13
#commons-httpclient.version=3.0.1    modify
commons-httpclient.version=3.1
commons-lang.version=2.6
#commons-logging.version=1.0.4        modify
commons-logging.version=1.1.3
#commons-logging-api.version=1.0.4    modify
commons-logging-api.version=1.1.3
#commons-math.version=2.1    modify
commons-math.version=3.1.1
commons-el.version=1.0
commons-fileupload.version=1.2
#commons-io.version=2.1        modify
commons-io.version=2.4
commons-net.version=3.1
core.version=3.1.1
coreplugin.version=1.3.2

#hsqldb.version=1.8.0.10    modify
hsqldb.version=2.0.0
#htrace.version=3.0.4    modify
htrace.version=3.1.0

ivy.version=2.1.0

jasper.version=5.5.12
jackson.version=1.9.13
#not able to figureout the version of jsp & jsp-api version to get it resolved throught ivy
# but still declared here as we are going to have a local copy from the lib folder
jsp.version=2.1
jsp-api.version=5.5.12
jsp-api-2.1.version=6.1.14
jsp-2.1.version=6.1.14
#jets3t.version=0.6.1    modify
jets3t.version=0.9.0
jetty.version=6.1.26
jetty-util.version=6.1.26
#jersey-core.version=1.8    modify
#jersey-json.version=1.8    modify
#jersey-server.version=1.8    modify
jersey-core.version=1.9
jersey-json.version=1.9
jersey-server.version=1.9
#junit.version=4.5    modify
junit.version=4.11
jdeb.version=0.8
jdiff.version=1.0.9
json.version=1.0

kfs.version=0.1

log4j.version=1.2.17
lucene-core.version=2.3.1

mockito-all.version=1.8.5
jsch.version=0.1.42

oro.version=2.0.8

rats-lib.version=0.5.1

servlet.version=4.0.6
servlet-api.version=2.5
#slf4j-api.version=1.7.5    modify
#slf4j-log4j12.version=1.7.5    modify
slf4j-api.version=1.7.10
slf4j-log4j12.version=1.7.10

wagon-http.version=1.0-beta-2
xmlenc.version=0.52
#xerces.version=1.4.4    modify
xerces.version=2.9.1

protobuf.version=2.5.0
guava.version=11.0.2
netty.version=3.6.2.Final

3. 用ant进行构建

这个时候在centos系统上，hadoop已经能够正常运行了，为了后面方便eclipse访问，关掉集群的权限校验（注意不要在生产环境这么做）。在mapred-site.xml增加一条配置：

<property>
<name>dfs.permissions</name>
<value>false</value>
</property>

重启集群。

将已经能在centos运行的hadoop2.7.3安装目录复制到windows，另外确保ant和eclipse已经配置好了，在ant命令中需要用到三个目录信息，以我本地为例：

eclipse：C:\eclipse
hadoop：E:\5-Hadoop\hadoop-2.7.3
hadoop2x-eclipse-plugin-master：E:\5-Hadoop\hadoop2x-eclipse-plugin-master

进入目录E:\5-Hadoop\hadoop2x-eclipse-plugin-master\src\contrib\eclipse-plugin\

输入命令进行构建：

ant jar -Dhadoop.version=2.7.3 -Declipse.home=C:\eclipse -Dhadoop.home=E:\5-Hadoop\hadoop-2.7.3

如果路径有空格的话，记得用双引号括起来，不过建议把软件都安装没有空格的路径上。等待几分钟，显示构建成功，最后的生成的hadoop-eclipse-plugin-2.7.3.jar存放在目录E:\5-Hadoop\hadoop2x-eclipse-plugin-master\build\contrib\eclipse-plugin下。

三、配置插件

1. 安装插件

将hadoop-eclipse-plugin-2.7.3.jar放在eclipse的plugin目录中：C:\eclipse\plugins，重启eclipse。

如果顺利，打开eclipse，通过Windows->Preferences->Hadoop Map/Reduce设置安装路径：

2. 设置location

通过Windows–> Show View –> Others –> Map/Redure Location ，通过图标新建一个location：

设置参数：

location name随便起一个，user name实际上也是默认就行，我之前以为需要填root，实际上什么名字都可以，重点是host跟两个port，在这里卡了一段时间。

实际上在centos端，我的主机名字是harry.com：

所以在windows端增加hosts配置：

192.168.0.210 harry.com

DFS Master的端口，根据hadoop的配置文件core-site.xml配置的端口去填：

至于Map/Reduce(V2) Master据说是job tracker的端口号（可是hadoop2已经用yarn了），在mapred-site.xml配置，我没有配这个，所以直接用9001的就行了。

完成之后，在左侧应该就可以看到hdfs里面的内容了：

如果host和port没配对，在连接hdfs的时候可能会报错：

An internal error occurred during: "Map/Reduce location status updater". java.lang.NullPointerExcept

如何还有其他报错，请先确保集群能正常运行，关闭centos的防火墙，如果能顺利走到这步，整个部署过程就已经完成了一半了。

四、运行MapReduce作业

1. 新建测试项目

新建hadoop里的hello world程序word count，并从源码中拷贝WordCount.java过来，如下：

把包名改成Test，源码如下：

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package Test;

import java.io.IOException;
import java.util.StringTokenizer;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
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 org.apache.hadoop.util.GenericOptionsParser;

public class WordCount {

  public static class TokenizerMapper
       extends Mapper<Object, Text, Text, IntWritable>{

    private final static IntWritable one = new IntWritable(1);
    private Text word = new Text();

    public void map(Object key, Text value, Context context
                    ) throws IOException, InterruptedException {
      StringTokenizer itr = new StringTokenizer(value.toString());
      while (itr.hasMoreTokens()) {
        word.set(itr.nextToken());
        context.write(word, one);
      }
    }
  }

  public static class IntSumReducer
       extends Reducer<Text,IntWritable,Text,IntWritable> {
    private IntWritable result = new IntWritable();

    public void reduce(Text key, Iterable<IntWritable> values,
                       Context context
                       ) throws IOException, InterruptedException {
      int sum = 0;
      for (IntWritable val : values) {
        sum += val.get();
      }
      result.set(sum);
      context.write(key, result);
    }
  }

  public static void main(String[] args) throws Exception {
    Configuration conf = new Configuration();
    String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
    if (otherArgs.length < 2) {
      System.err.println("Usage: wordcount <in> [<in>...] <out>");
      System.exit(2);
    }
    Job job = Job.getInstance(conf, "word count");
    job.setJarByClass(WordCount.class);
    job.setMapperClass(TokenizerMapper.class);
    job.setCombinerClass(IntSumReducer.class);
    job.setReducerClass(IntSumReducer.class);
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(IntWritable.class);
    for (int i = 0; i < otherArgs.length - 1; ++i) {
      FileInputFormat.addInputPath(job, new Path(otherArgs[i]));
    }
    FileOutputFormat.setOutputPath(job,
      new Path(otherArgs[otherArgs.length - 1]));
    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }
}

实际上，刚开始构建的时候，会报错：

The type java.util.Map$Entry cannot be resolved. It is indirectly referenced from required .class files    WordCount.java    /WordCount/src/Test    line 1    Java Problem

查了一下，原来我的eclipse版本是Helios，而java版本是1.8，不支持。于是有两个选择：降到java1.8以下或者换更高的eclipse版本，我的选择是升eclipse版本到juno版本，问题解决。

2. 设置运行参数并运行

点击WordCount类，右键Run As –> Run Configurations ，点击Arguments，填写输入目录，输出目录参数：

运行，报错：

Exception in thread "main" java.io.IOException: (null) entry in command string: null chmod 0700 C:\tmp\hadoop-Administrator\mapred\staging\Administrator134847124\.staging
...

设置环境变量HADOOP_HOME为E:\5-Hadoop\hadoop-2.7.3，在 https://github.com/SweetInk/hadoop-common-2.7.1-bin 中下载winutils.exe,libwinutils.lib拷贝到%HADOOP_HOME%\bin目录，重新运行，嗯，重新报错：

Exception in thread "main" java.lang.UnsatisfiedLinkError: org.apache.hadoop.io.nativeio.NativeIO$Windows.access0(Ljava/lang/String;I)Z
...

在https://github.com/SweetInk/hadoop-common-2.7.1-bin中下载hadoop.dll，并拷贝到c:\windows\system32目录中。重新执行，报WARN：

log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

在项目的src下面新建file名为log4j.properties的文件，内容为：

# Configure logging for testing: optionally with log file
#log4j.rootLogger=debug,appender
log4j.rootLogger=info,appender
#log4j.rootLogger=error,appender
#\u8F93\u51FA\u5230\u63A7\u5236\u53F0
log4j.appender.appender=org.apache.log4j.ConsoleAppender
#\u6837\u5F0F\u4E3ATTCCLayout
log4j.appender.appender.layout=org.apache.log4j.TTCCLayout

因为刚才其实已经运行成功了，所以这次需要先删掉hdfs中的out1目录，然后运行，然后在console中会打印出这次任务的运行数据，最后在hdfs中查看运行结果：